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IS-IS Commands
This module describes the commands used to configure and monitor the Intermediate System-to-Intermediate System (IS-IS) .
For detailed information about IS-IS concepts, configuration tasks, and examples, see the Implementing IS-IS on module in the Routing Configuration Guide for Cisco NCS 6000 Series Routers.
- address-family (IS-IS)
- address-family multicast topology (IS-IS)
- adjacency-check disable
- attached-bit receive ignore
- attached-bit send
- circuit-type
- clear isis process
- clear isis route
- clear isis statistics
- csnp-interval
- default-information originate (IS-IS)
- disable (IS-IS)
- distance (IS-IS)
- fast-reroute per-link (IS-IS)
- fast-reroute per-prefix (IS-IS)
- fast-reroute per-link priority-limit (IS-IS)
- fast-reroute per-prefix load-sharing disable (IS-IS)
- fast-reroute per-prefix tiebreaker (IS-IS)
- hello-interval (IS-IS)
- hello-multiplier
- hello-padding
- hello-password
- hello-password keychain
- hello-password accept
- hostname dynamic disable
- ignore-lsp-errors
- interface (IS-IS)
- ipfrr lfa
- ipfrr lfa exclude interface
- ispf
- is-type
- log adjacency changes (IS-IS)
- log pdu drops
- lsp fast-flood threshold
- lsp-gen-interval
- lsp-interval
- lsp-mtu
- lsp-password
- lsp-password accept
- lsp-refresh-interval
- maximum-paths (IS-IS)
- maximum-redistributed-prefixes (IS-IS)
- max-lsp-lifetime
- mesh-group (IS-IS)
- metric (IS-IS)
- metric-style narrow
- metric-style transition
- metric-style wide
- min-lsp-arrivaltime
- mpls ldp auto-config
- mpls ldp sync (IS-IS)
- mpls traffic-eng (IS-IS)
- mpls traffic-eng multicast-intact (IS-IS)
- mpls traffic-eng path-selection ignore overload
- mpls traffic-eng router-id (IS-IS)
- mpls traffic-eng srlg (IS-IS)
- net
- nsf (IS-IS)
- nsf interface-expires
- nsf interface-timer
- nsf lifetime (IS-IS)
- passive (IS-IS)
- point-to-point
- priority (IS-IS)
- propagate level
- redistribute (IS-IS)
- retransmit-interval (IS-IS)
- retransmit-throttle-interval
- router isis
- set-attached-bit
- set-overload-bit
- show isis
- show isis adjacency
- show isis adjacency-log
- show isis checkpoint adjacency
- show isis checkpoint interface
- show isis checkpoint lsp
- show isis database
- show isis database-log
- show isis fast-reroute
- show isis hostname
- show isis interface
- show isis lsp-log
- show isis mesh-group
- show isis mpls traffic-eng adjacency-log
- show isis mpls traffic-eng advertisements
- show isis mpls traffic-eng tunnel
- show isis neighbors
- show isis protocol
- show isis route
- show isis spf-log
- show isis statistics
- show isis topology
- show protocols (IS-IS)
- shutdown (IS-IS)
- single-topology
- snmp-server traps isis
- spf-interval
- spf prefix-priority (IS-IS)
- summary-prefix (IS-IS)
- suppressed
- tag (IS-IS)
- topology-id
- trace (IS-IS)
address-family (IS-IS)
To enter address family configuration mode for configuring Intermediate System-to-Intermediate System (IS-IS) routing that use standard IP Version 4 (IPv4) and IP Version 6 (IPv6) address prefixes, use the address-family command in router configuration or interface configuration mode. To disable support for an address family, use the no form of this command.
address-family { ipv4 | ipv6 } { unicast | mulitcast }
no address-family { ipv4 | ipv6 } { unicast | multicast }
Syntax Description
ipv4
Specifies IPv4 address prefixes.
ipv6
Specifies IPv6 address prefixes.
unicast
Specifies unicast address prefixes.
multicast
Specifies multicast address prefixes.
Command Default
An address family is not specified. The default subaddress family (SAFI) is unicast.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the address family command to place the router or interface in address family configuration mode. In router address family configuration mode, you can configure routing that uses standard IPv4 or IPv6 address prefixes. An address family must be specified in interface configuration mode. In interface address family configuration mode, you can alter interface parameters for IPv4or IPv6.
You must specify an address family in order to configure parameters that pertain to a single address family.
Task ID
Examples
The following example shows how to configure the IS-IS router process with IPv4 unicast address prefixes:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface gigabitEthernet 0/1/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)#address-family multicast topology (IS-IS)
To enable a multicast topology when configuring Intermediate System-to-Intermediate System (IS-IS) routing (or to place a given topology within the IS-IS interface), use the address-family multicast topology command with either IPv4 or IPv6 address prefix in the appropriate configuration mode. To disable a multicast topology in IS-IS, use the no form of this command.
address-family { ipv4 | ipv6 } multicast topology topo-name [ maximum prefix prefix-limit ]
no address-family { ipv4 | ipv6 } multicast topology topo-name
Syntax Description
ipv4
Specifies IPv4 address prefixes.
ipv6
Specifies IPv6 address prefixes.
multicast
Specifies multicast address prefixes.
topology topo-name
Specifies the name of the topology.
maximum prefix
Specifies maximum number of prefixes that a routing table can have.
prefix-limit
Maximum number of prefixes. Range is from 32 to 2,000,000.
Command Default
An address family for multicast topology is not specified. The default subaddress family (SAFI) is unicast.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the address family multicast topology command to place the router or interface in address family configuration mode. In router address family configuration mode, you can associate an IS-IS topology ID with the topology you have created to add connected and local routes to a specific routing table.
Task ID
Examples
The following example shows how to configure the IS-IS router topology with an IPv4 multicast address prefix:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv6 multicast topology green RP/0/RP0/CPU0:router(config-isis-af)#or
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface gigabitethernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 multicast topology green RP/0/RP0/CPU0:router(config-isis-if-af)#adjacency-check disable
To suppress Intermediate System-to-Intermediate System (IS-IS) IP Version 4 (IPv4) or IP Version 6 (IPv6) protocol-support consistency checks that are performed prior to forming adjacencies on hello packets, use the adjacency-check disable command in address family configuration mode. To remove this function, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
IS-IS performs consistency checks on hello packets and forms an adjacency only with a neighboring router that supports the same set of protocols. A router running IS-IS for both IPv4 and IPv6 does not form an adjacency with a router running IS-IS for IPv4 only.
Use the adjacency-check disable command to suppress the consistency checks for IPv6 IS-IS and allow an IPv4 IS-IS router to form an adjacency with a router running IPv4 IS-IS and IPv6. IS-IS never forms an adjacency between a router running IPv4 IS-IS only and a router running IPv6 only.
In addition, the adjacency-check disable command suppresses the IPv4 or IPv6 subnet consistency check and allows IS-IS to form an adjacency with other routers regardless of whether they have an IPv4 or IPv6 subnet in common.
Task ID
Examples
The command in the following example disables the adjacency checks:
The following example shows how the network administrator introduces IPv6 into an existing IPv4 IS-IS network and ensures that the checking of hello packet checks from adjacent neighbors is disabled until all neighbor routers are configured to use IPv6:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv6 |ipv4 RP/0/RP0/CPU0:router(config-isis-af)# adjacency-check disableattached-bit receive ignore
To ignore the attached bit in a received Level 1 link-state packet (LSP), use the attached-bit receive ignore command in address family configuration mode. To remove the attached-bit receive ignore command from the configuration file and restore the system to its default condition, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to configure to ignore the attached bit in a received LSP:
RP/0/RP0/CPU0:router(config)# router isis isp1 RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# attached-bit receive ignoreattached-bit send
To configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit in the Level 1 link-state packet (LSP), use the attached-bit send command in address family configuration mode. To remove the attached-bit send command from the configuration file and restore the system to its default condition, use the no form of this command.
Syntax Description
always-set
Specifies to always set the attached bit in the LSP.
never-set
Specifies to never set the attached bit in the LSP.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the attached-bit send command to set an IS-IS instance with an attached bit in the Level 1 LSP that allows another IS-IS instance to redistribute Level 2 topology. The attached bit is used when the Level 2 connectivity from another IS-IS instance is advertised by the Level 1 attached bit.
Cisco IOS XR software does not support multiple Level 1 areas in a single IS-IS routing instance; however the equivalent functionality is achieved by redistribution of routes between two IS-IS instances by using the redistribute (IS-IS) command.
The attached bit is configured for a specific address family only if the single-topology command is not configured.
Note
If connectivity for the Level 2 instance is lost, the attached bit in the Level 1 instance LSP continues sending traffic to the Level 2 instance and causes the traffic to be dropped.
Task ID
Examples
The following example shows how to configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit:
RP/0/RP0/CPU0:router(config)# router isis isp1 RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# attached-bit send always-setcircuit-type
To configure the type of adjacency used for the Intermediate System-to-Intermediate System (IS-IS) protocol, use the circuit-type command in interface configuration mode. To reset the circuit type to Level l and Level 2, use the no form of this command.
Syntax Description
level-1
Establishes only Level 1 adjacencies over an interface.
level-1-2
Establishes both Level 1 and Level 2 adjacencies, if possible.
level-2-only
Establishes only Level 2 adjacencies over an interface.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Adjacencies may not be established even if allowed by the circuit-type command. The proper way to establish adjacencies is to configure a router as a Level 1, Level 1 and Level 2, or Level 2-only system using the is-type command. Only on networking devices that are between areas (Level 1 and Level 2 networking devices) should you configure some interfaces to be Level 2-only to prevent wasting bandwidth by sending out unused Level 1 hello packets. Remember that on point-to-point interfaces, the Level 1 and Level 2 hello packets are in the same packet.
Task ID
Examples
The following example shows how to configure a Level 1 adjacency with its neighbor on GigabitEthernetinterface 0/2/0/0 and Level 2 adjacencies with all Level 2-capable routers on GigabitEthernet interface 0/5/0/2:
RP/0//CPU0:router(config)# router isis isp RP/0//CPU0:router(config-isis)# is-type level-1-2 RP/0//CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0 RP/0//CPU0:router(config-isis-if)# circuit-type level-1 RP/0//CPU0:router(config-isis-if)# exit RP/0//CPU0:router(config-isis)# interface GigabitEthernet 0/5/0/2 RP/0//CPU0:router(config-isis-if)# circuit-type level-2-onlyIn this example, only Level 2 adjacencies are established because the is-type command is configured:
RP/0//CPU0:router(config)# router isis isp RP/0//CPU0:router(config-isis)# is-type level-2-only RP/0//CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0 RP/0//CPU0:router(config-isis-if)# circuit-type level-1-2clear isis process
To clear the link-state packet (LSP) database and adjacency database sessions for an Intermediate System-to-Intermediate System (IS-IS) instance or all IS-IS instances, use the clear isis process command in XR EXEC mode.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the clear isis process command without any keyword to clear all the IS-IS instances. Add the instance instance-id keyword and argument to clear the specified IS-IS instance.
Task ID
Examples
The following example shows the IS-IS LSP database and adjacency sessions being cleared for instance 1:
RP/0/RP0/CPU0:router# clear isis instance 1 processclear isis route
To clear the Intermediate System-to-Intermediate System (IS-IS) routes in a topology, use the clear isis route command in XR EXEC mode.
clear isis [ instance instance-id ] { afi-all | ipv4 | ipv6 } { unicast | multicast | safi-all } [ topology topo-name ] route
Syntax Description
instance instance-id
(Optional) Specifies IS-IS sessions for the specified IS-IS instance only.
afi-all
Specifies IP Version 4 (IPv4) and IP Version 6 (IPv6) address prefixes.
ipv4
Specifies IPv4 address prefixes.
ipv6
Specifies IPv6 address prefixes.
unicast
Specifies unicast address prefixes.
multicast
Specifies multicast address prefixes.
safi-all
Specifies all secondary address prefixes.
topology topo-name
(Optional) Specifies topology table information and name of the topology table.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the clear isis route command to clear the routes from the specified topology or all routes in all topologies if no topology is specified.
Task ID
Examples
The following example shows how to clear the routes with IPv4 unicast address prefixes:
RP/0/RP0/CPU0:router# clear isis ipv4 unicast routeclear isis statistics
To clear the Intermediate System-to-Intermediate System (IS-IS) statistics, use the clear isis statistics command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Clears IS-IS sessions for the specified IS-IS instance only.
type
Interface type. For more information, use the question mark (?) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark (?) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the clear isis statistics command to clear the information displayed by the show isis statistics command.
Task ID
csnp-interval
To configure the interval at which periodic complete sequence number PDU (CSNP) packets are sent on broadcast interfaces, use the csnp-interval command in interface configuration mode. To restore the default value, use the no form of this command.
Syntax Description
seconds
Interval (in seconds) of time between transmission of CSNPs on multiaccess networks. This interval applies only for the designated router. Range is 0 to 65535 seconds.
level { 1 | 2 }
(Optional) Specifies the interval of time between transmission of CSNPs for Level 1 or Level 2 independently.
Command Default
seconds : 10 seconds
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The csnp-interval command applies only to the designated router (DR) for a specified interface. Only DRs send CSNP packets to maintain database synchronization. The CSNP interval can be configured independently for Level 1 and Level 2.
Use of the csnp-interval command on point-to-point subinterfaces makes sense only in combination with the IS-IS mesh-group feature.
Task ID
default-information originate (IS-IS)
To generate a default route into an Intermediate System-to-Intermediate System (IS-IS) routing domain, use the default-information originate command in address family configuration mode. To remove the default-information originate command from the configuration file and restore the system to its default condition, use the no form of this command.
default-information originate [ route-policy route-policy-name ]
no default-information originate [ external | route-policy route-policy-name ]
Syntax Description
route-policy
(Optional) Defines the conditions for the default route.
route-policy-name
(Optional) Name for the route policy.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
If a router configured with the default-information originate command has a route to 0.0.0.0 in the routing table, IS-IS originates an advertisement for 0.0.0.0 in its link-state packets (LSPs).
Without a route policy, the default is advertised only in Level 2 LSPs. For Level 1 routing, there is another process to find the default route, which is to look for the closest Level 1 and Level 2 router. The closest Level 1 and Level 2 router can be found by looking at the attached-bit (ATT) in Level 1 LSPs.
A route policy can be used for two purposes:
Task ID
Examples
The following example shows how to generate a default external route into an IS-IS domain:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# default-information originatedisable (IS-IS)
To disable the Intermediate System-to-Intermediate System (IS-IS) topology on a specified interface, use the disable command in interface address family configuration mode. To remove this function, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to disable the IS-IS protocol for IPv4 unicast on GigabitEthernet interface 0/1/0/1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# disabledistance (IS-IS)
To define the administrative distance assigned to routes discovered by the Intermediate System-to-Intermediate System (IS-IS) protocol, use the distance command in address family configuration mode. To remove the distance command from the configuration file and restore the system to its default condition in which the software removes a distance definition, use the no form of this command.
distance weight [ prefix mask | prefix/length | | [ prefix-list-name ] ]
no distance [ weight ] [ prefix mask | prefix/length | | [ prefix-list-name ] ]
Syntax Description
weight
Administrative distance to be assigned to IS-IS routes. Range is 1 to 255.
prefix
(Optional) The prefix argument specifies the IP address in four-part, dotted-decimal notation.
mask
(Optional) IP address mask.
/length
(Optional) The length of the IP prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value. Range is 0 to 32 for IPv4 addresses and 0 to 128 for IPv6 addresses.
prefix-list-name
(Optional) List of routes to which administrative distance applies.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
An administrative distance is an integer from 1 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means that the routing information source cannot be trusted at all and should be ignored. Weight values are subjective; no quantitative method exists for choosing weight values.
Use the distance command to configure the administrative distances applied to IS-IS routes when they are inserted into the Routing Information Base (RIB), and influence the likelihood of these routes being preferred over routes to the same destination addresses discovered by other protocols.
The address/prefix-length argument defines to which source router the distance applies. In other words, each IS-IS route is advertised by another router, and that router advertises an address that identifies it. This source address is displayed in the output of the show isis route detail command.
The distance command applies to the routes advertised by routers whose address matches the specified prefix. The prefix-list-name argument can then be used to refine this further so that the distance command affects only specific routes.
Task ID
Examples
In the following example, a distance of 10 is assigned to all routes to 2.0.0.0/8 and 3.0.0.0/8 (or more specific prefixes) that are advertised by routers whose ID is contained in 1.0.0.0/8. A distance of 80 is assigned to all other routes.
RP/0//CPU0:router(config)# ipv4 prefix-list target_routes RP/0//CPU0:router(config-ipv4_pfx)# permit 2.0.0.0/8 RP/0//CPU0:router(config-ipv4_pfx)# permit 3.0.0.0/8 RP/0//CPU0:router(config-ipv4_pfx)# deny 0.0.0.0/0 RP/0//CPU0:router(config-ipv4_pfx)# exit RP/0//CPU0:router(config)# router isis isp RP/0//CPU0:router(config-isis)# address-family ipv4 unicast RP/0//CPU0:router(config-isis-af)# distance 10 1.0.0.0/8 target_routes RP/0//CPU0:router(config-isis-af)# distance 80Related Commands
Command
Description
Configures the IS-IS routing protocol and specifies an IS-IS instance.
Displays summary information about the IS-IS instance.
show isis route detail
Displays link-state packet (LSP) details.
fast-reroute per-link (IS-IS)
To enable IP fast reroute (IPFRR) loop-free alternate (LFA) prefix independent per-link computation, use the fast-reroute per-link command in interface address family configuration mode. To disable this feature, use the no form of this command.
fast-reroute per-link [ exclude interface type interface-path-id | level { 1 | 2 } | lfa-candidate interface type interface-path-id ]
no fast-reroute per-link
Syntax Description
exclude Specifies fast-reroute (FRR ) loop-free alternate (LFA) computation exclusion information
level {1 | 2} Configures FRR LFA computation for one level only.
lfa-candidate Specifies FRR LFA computation candidate information
interface Specifies an interface that needs to be either excluded from FRR LFA computation (when used with exclude keyword) or to be included to LFA candidate list in FRR LFA computation (when used with the lfa-candidate keyword).
type Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
This example shows how to configure per-link fast-reroute LFA computation for the IPv4 unicast topology at Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface POS0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-link level 1fast-reroute per-prefix (IS-IS)
To enable IP fast reroute (IPFRR) loop-free alternate (LFA) prefix dependent computation, use the fast-reroute per-prefix command in interface address family configuration mode. LFA is supported only on Enhanced Ethernet line card. To disable this feature, use the no form of this command.
fast-reroute per-prefix [ exclude interface type interface-path-id | level { 1 | 2 } | lfa-candidate interface type interface-path-id | | remote-lfa { maximum-metric metric-value | tunnel mpls-ldp } [ level { 1 | 1 } ] ]
no fast-reroute per-prefix
Syntax Description
exclude Specifies fast-reroute (FRR ) loop-free alternate (LFA) computation exclusion information
level {1 | 2} Configures FRR LFA computation for one level only.
lfa-candidate Specifies FRR LFA computation candidate information
interface Specifies an interface that needs to be either excluded from FRR LFA computation (when used with exclude keyword) or to be included to LFA candidate list in FRR LFA computation (when used with the lfa-candidate keyword).
type Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
This example shows how to configure per-prefix fast-reroute LFA computation for the IPv4 unicast topology at Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface POS0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# fast-reroute per-prefix level 1fast-reroute per-link priority-limit (IS-IS)
To enable the IP fast reroute (IPFRR) loop-free alternate (LFA) prefix independent per-link computation, use the fast-reroute per-link priority-limit command in address family configuration mode. To disable this feature, use the no form of this command.
fast-reroute per-link priority-limit { critical | high | medium } level { 1 | 2 }
no fast-reroute per-link priority-limit
Syntax Description
critical
Enables LFA omputation for critical priority prefixes only.
high
Enables LFA computation for for criticaland high priority prefixes.
medium
Enables LFA computation for for critical, high, and medium priority prefixes.
level {1|2}
Sets priority-limit for routing Level 1 or Level 2 independently.
Command Modes
IPv4 unicast address family configuration
IPv4 multicast address family configuration
IPv6 unicast address family configuration
IPv6 multicast address family configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
This example shows how to configure fast-reroute prefix independent per-link computation for critical priority prefixes for level 1 only:RP/0/RP0/CPU0:router#configure RP/0/RP0/CPU0:router(config)#router isis isp_lfa RP/0/RP0/CPU0:router(config-isis)#address-family ipv4 RP/0/RP0/CPU0:router(config-isis-af)#fast-reroute per-link priority-limit critical level 1fast-reroute per-prefix load-sharing disable (IS-IS)
To disable load sharing prefixes across multiple backups, use the fast-reroute per-prefix load-sharing disable command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
This example shows how to disable load-sharing prefixes across multiple backups for level 1 routes:RP/0/RP0/CPU0:router#configure RP/0/RP0/CPU0:router(config)#router isis isp_lfa RP/0/RP0/CPU0:router(config-isis)#address-family ipv4 RP/0/RP0/CPU0:router(config-isis-af)#fast-reroute per-prefix load-sharing disable level 1fast-reroute per-prefix tiebreaker (IS-IS)
To configure tie-breaker for multiple backups, use the fast-reroute per-prefix tiebreaker command in IPv4 address family configuration mode. To disable tie-breaker configuration, use the no form of this command.
fast-reroute per-prefix tiebreaker [ downstream | lc-disjoint | lowest-backup-metric | node-protecting | primary-path | secondary-path ] index index_number level {1 | 2}
no fast-reroute per-prefix tiebreaker
Syntax Description
downstream
Configures to prefer backup path via downstream node, in case of tie-breaker.
lc-disjoint
Configures to prefer Prefer line card disjoint backup path.
lowest-backup-metric
Configures to prefer backup path with lowest total metric.
node-protecting
Configures to prefer node protecting backup path.
primary-path
Configures to prefer backup path from ECMP set.
secondary-path
Configures to prefer non-ECMP backup path.
index
Sets preference order among tie-breakers.
index_number
Value for the index. Range is 1-255.
level {1 | 2}
Configures tiebreaker for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
This example shows how to configure preference of backup path via downstream node in case of a tie-breaker for selection of backup path from multiple backup paths:RP/0/RP0/CPU0:router#configure RP/0/RP0/CPU0:router(config)#router isis isp_lfa RP/0/RP0/CPU0:router(config-isis)#address-family ipv4 RP/0/RP0/CPU0:router(config-isis-af)#fast-reroute per-prefix tiebreaker downstream index 255hello-interval (IS-IS)
To specify the length of time between consecutive hello packets sent by the Intermediate System-to-Intermediate System (IS-IS) protocol software, use the hello-interval command in interface configuration mode. To restore the default value, use the no form of this command.
Syntax Description
seconds
Integer value (in seconds) for the length of time between consecutive hello packets. By default, a value three times the hello interval seconds is advertised as the hold time in the hello packets sent. (That multiplier of three can be changed by using the hello-multiplier command.) With smaller hello intervals, topological changes are detected more quickly, but there is more routing traffic. Range is 1 to 65535 seconds.
level { 1 | 2 }
(Optional) Specifies the hello interval for Level 1 and Level 2 independently. For broadcast interfaces only.
Command Default
seconds : 10 seconds
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The hello interval can be configured independently for Level 1 and Level 2, except on serial point-to-point interfaces. (Because only a single type of hello packet is sent on serial links, it is independent of Level 1 or Level 2.) Configuring Level 1 and Level 2 independently is used on LAN interfaces.
Note
A shorter hello interval gives quicker convergence, but increases bandwidth and CPU usage. It might also add to instability in the network.
A slower hello interval saves bandwidth and CPU. Especially when used in combination with a higher hello multiplier, this strategy may increase overall network stability.
For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.
Task ID
Examples
The following example shows how to configure TenGigE interface 0/6/0/0 to advertise hello packets every 5 seconds for Level 1 topology routes. This situation causes more traffic than configuring a longer interval, but topological changes are detected more quickly.
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface TenGigE 0/6/0/0 RP/0/RP0/CPU0:router(config-isis-if)# hello-interval 5 level 1hello-multiplier
To specify the number of Intermediate System-to-Intermediate System (IS-IS) hello packets a neighbor must miss before the router should declare the adjacency as down, use the hello-multiplier command in interface configuration mode. To restore the default value, use the no form of this command.
hello-multiplier multiplier [ level { 1 | 2 } ]
no hello-multiplier [multiplier] [ level { 1 | 2 } ]
Syntax Description
multiplier
Advertised hold time in IS-IS hello packets is set to the hello multiplier times the hello interval. Range is 3 to 1000. Neighbors declare an adjacency to this down router after not having received any IS-IS hello packets during the advertised hold time. The hold time (and thus the hello multiplier and the hello interval) can be set on an individual interface basis, and can be different between different networking devices in one area.
Using a smaller hello multiplier gives faster convergence, but can result in more routing instability. Increase the hello multiplier to a larger value to help network stability when needed. Never configure a hello multiplier to a value lower than the default value of 3.
level { 1 | 2 }
(Optional) Specifies the hello multiplier independently for Level 1 or Level 2 adjacencies.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The “holding time” carried in an IS-IS hello packet determines how long a neighbor waits for another hello packet before declaring the neighbor to be down. This time determines how quickly a failed link or neighbor is detected so that routes can be recalculated.
Use the hello-multiplier command in circumstances where hello packets are lost frequently and IS-IS adjacencies are failing unnecessarily. You can raise the hello multiplier and lower the hello interval (hello-interval (IS-IS) command) correspondingly to make the hello protocol more reliable without increasing the time required to detect a link failure.
On point-to-point links, there is only one hello for both Level 1 and Level 2. Separate Level 1 and Level 2 hello packets are also sent over nonbroadcast multiaccess (NBMA) networks in multipoint mode, such as X.25, Frame Relay, and ATM.
Task ID
Examples
The following example shows how the network administrator wants to increase network stability by making sure an adjacency goes down only when many (ten) hello packets are missed. The total time to detect link failure is 60 seconds. This strategy ensures that the network remains stable, even when the link is fully congested.
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet /2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# hello-interval 6 RP/0/RP0/CPU0:router(config-isis-if)# hello-multiplier 10hello-padding
To configure padding on Intermediate System-to-Intermediate System (IS-IS) hello protocol data units (IIH PDUs) for all IS-IS interfaces on the router, use the hello-padding command in interface configuration mode. To suppress padding, use the no form of this command.
hello-padding { disable | sometimes } [ level { 1 | 2 } ]
no hello-padding { disable | sometimes } [ level { 1 | 2 } ]
Syntax Description
disable
Suppresses hello padding.
sometimes
Enables hello padding during adjacency formation only.
level { 1 | 2 }
(Optional) Specifies hello padding for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
You might want to suppress hello padding to conserve network resources. The lower the circuit speed, the higher the percentage of padding overhead. Before suppressing the hello padding, you should know your physical and data link layer configurations and have control over them, and also know your router configuration at the network layer.
For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.
Task ID
Examples
The following example shows how to suppress IS-IS hello padding over local area network (LAN) circuits for interface GigabitEthernet 0/2/0/1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# hello-padding disablehello-password
To configure the authentication password for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password command in interface configuration mode. To disable authentication, use the no form of this command.
hello-password [ hmac-md5 | text ] [ clear | encrypted ] password [ level { 1 | 2 } ] [send-only]
no hello-password [ hmac-md5 | text ] [ clear | encrypted ] password [ level { 1 | 2 } ] [send-only]
Syntax Description
hmac-md5
(Optional) Specifies that the password use HMAC-MD5 authentication.
text
(Optional) Specifies that the password use clear text password authentication.
clear
(Optional) Specifies that the password be unencrypted.
encrypted
(Optional) Specifies that the password be encrypted using a two-way algorithm.
password
Authentication password you assign for an interface.
level { 1 | 2 }
(Optional) Specifies whether the password is for a Level 1 or a Level 2 protocol data unit (PDU).
send-only
(Optional) Specifies that the password applies only to protocol data units (PDUs) that are being sent and does not apply to PDUs that are being received.
Command Default
Both Level 1 and Level 2 are configured if no level is specified.
password: encrypted text
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When a text password is configured, it is exchanged as clear text. Therefore, the hello-password command provides limited security.
When an hmac-md5 password is configured, the password is never sent over the network and is instead used to calculate a cryptographic checksum to ensure the integrity of the exchanged data.
For point-to-point links, IS-IS sends only a single hello for Level 1 and Level 2, making the level keyword meaningless on point-to-point links. To modify hello parameters for a point-to-point interface, omit the level keyword.
Task ID
Examples
The following example shows how to configure a password with HMAC-MD5 authentication for hello packets running on GigabitEthernet 0/2/0/3 interface:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/3 RP/0/RP0/CPU0:router(config-isis-if)# hello-password hmac-md5 clear mypasswordhello-password keychain
To configure the authentication password keychain for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password keychain command in interface configuration mode. To disable the authentication password keychain, use the no form of this command.
hello-password keychain keychain-name [ level { 1 | 2 } ] [send-only]
no hello-password keychain keychain-name [ level { 1 | 2 } ] [send-only]
Syntax Description
keychain
Keyword that specifies the keychain to be configured. An authentication password keychain is a sequence of keys that are collectively managed and used for authenticating a peer-to-peer group.
keychain-name
Specifies the name of the keychain.
level { 1 | 2 }
(Optional) Specifies whether the keychain is for a Level 1 or a Level 2 protocol data unit (PDU).
send-only
(Optional) Specifies that the keychain applies only to protocol data units (PDUs) that are being sent and does not apply to PDUs that are being received.
Command Default
Both Level 1 and Level 2 are configured if no level is specified.
password: encrypted text
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Specify a keychain to enable keychain authentication between two IS-IS peers. Use the keychain keychain-name keyword and argument to implement hitless key rollover for authentication.
Task ID
Examples
The following example shows how to configure a password keychain for level 1, send only authentication on a GigabitEthernet interface:
RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/0 RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config-isis-if)# hello-password keychain mykeychain level 1 send-onlyhello-password accept
To configure an additional authentication password for an Intermediate System-to-Intermediate System (IS-IS) interface, use the hello-password accept command in interface configuration mode. To disable authentication, use the no form of this command.
hello-password accept { clear | encrypted } password [ level { 1 | 2 } ]
no hello-password accept { clear | encrypted } password [ level { 1 | 2 } ]
Syntax Description
clear
Specifies that the password be unencrypted.
encrypted
Specifies that the password be encrypted using a two-way algorithm.
password
Authentication password you assign.
level { 1 | 2 }
(Optional) Specifies the password for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the hello-password accept command to add an additional password for an IS-IS interface. An authentication password must be configured using the hello-password command before an accept password can be configured for the corresponding level.
Task ID
Examples
The following example shows how to configure a password:
RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/3 RP/0/RP0/CPU0:routerRP/0/RP0/CPU0:router(config-isis)# hello-password accept encrypted 111D1C1603hostname dynamic disable
To disable Intermediate System-to-Intermediate System (IS-IS) routing protocol dynamic hostname mapping, use the hostname dynamic command in router configuration mode. To remove the specified command from the configuration file and restore the system to its default condition, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
In an IS-IS routing domain, each router is represented by a 6-byte hexadecimal system ID. When network administrators maintain and troubleshoot networking devices, they must know the router name and corresponding system ID.
Link-state packets (LSPs) include the dynamic hostname in the type, length, and value (TLV) which carries the mapping information across the entire domain. Every router in the network, upon receiving the TLV from an LSP, tries to install it in a mapping table. The router then uses the mapping table when it wants to convert a system ID to a router name.
To display the entries in the mapping tables, use the show isis hostname command.
Task ID
Examples
The following example shows how to disable dynamic mapping of hostnames to system IDs:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# hostname dynamic disableignore-lsp-errors
To override the default setting of a router to ignore Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs) that are received with internal checksum errors, use the ignore-lsp-errors disable command in router configuration mode. To enable ignoring IS-IS LSP errors, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The IS-IS protocol definition requires that a received LSP with an incorrect data-link checksum be purged by the receiver, which causes the initiator of the packet to regenerate it. However, if a network has a link that causes data corruption and at the same time is delivering LSPs with correct data-link checksums, a continuous cycle of purging and regenerating large numbers of packets can occur. Because this situation could render the network nonfunctional, use this command to ignore these LSPs rather than purge the packets.
The receiving network devices use link-state packets to maintain their routing tables.
Task ID
interface (IS-IS)
To configure the Intermediate System-to-Intermediate System (IS-IS) protocol on an interface, use the interface command in router configuration mode. To disable IS-IS routing for interfaces, use the no form of this command.
Syntax Description
type
Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
An address family must be established on the IS-IS interface before the interface is enabled for IS-IS protocol operation.
Task ID
Examples
The following example shows how to enable an IS-IS multitopology configuration for IPv4 on GigabitEthernet interface 0/3/0/0:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# net 49.0000.0000.0001.00 RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# metric-style wide level 1 ! RP/0/RP0/CPU0:router(config)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-if)# ipv4 address 2001::1/64ipfrr lfa
To enable the IP fast reroute (IPFRR) loop-free alternate (LFA) computation, use the ipfrr lfa command in interface address family configuration mode. To disable this feature, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the ipfrr lfa command to compute loop-free alternates for all links or neighbors in the event of a link failure.
To enable node protection on broadcast links, IPRR and bidirectional forwarding detection (BFD) must be enabled on the interface under IS-IS. See Cisco IOS XR Interface and Hardware Configuration Guide for information on configuring BFD.
Note
Multiprotocol Label Switching (MPLS) FRR and IPFRR cannot be configured on the same interface simultaneously.
Task ID
Examples
The following example shows how to configure IPFRR for the IPv4 unicast topology at Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface POS0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# ipfrr lfa level 1ipfrr lfa exclude interface
To exclude an interface from the IP fast reroute (IPFRR) loop-free alternate (LFA) computation, use the ipfrr lfa exclude interface command in interface address family configuration mode. To disable this feature, use the no form of this command.
ipfrr lfa exclude interface type interface-path-id
no ipfrr lfa exclude interface type interface-path-id
Syntax Description
type
Interface type. For more information, use the question mark (?) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark (?) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the ipfrr lfa command to compute loop-free alternates for all links or neighbors in the event of a link failure.
To enable node protection on broadcast links, IPRR and bidirectional forwarding detection (BFD) must be enabled on the interface under IS-IS. See Cisco IOS XR Interface and Hardware Configuration Guide for information on configuring BFD.
Note
Multiprotocol Label Switching (MPLS) FRR and IPFRR cannot be configured on the same interface simultaneously.
Task ID
Examples
The following example shows how to configure to exclude 0/1/0/0 interface from IPFRR LFA:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface POS0/1/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# ipfrr lfa exclude interface POS0/1/0/0ispf
To configure the incremental shortest path first (iSPF) algorithm to calculate network topology, use the ispf command in address family configuration mode. To disable this algorithm function, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The iSPF algorithm may be used to reduce the processor load when IS-IS needs to recalculate its topology after minor changes.
Task ID
is-type
To configure the routing level for an Intermediate System-to-Intermediate System (IS-IS) area, use the is-type command in router configuration mode. To set the routing level to the default level, use the no form of this command.
Syntax Description
level-1
Specifies that the router perform only Level 1 (intra-area) routing. This router learns only about destinations inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.
level-1-2
Specifies that the router perform both Level 1 and Level 2 routing.
level-2-only
Specifies that the routing process acts as a Level 2 (interarea) router only. This router is part of the backbone, and does not communicate with Level 1-only routers in its own area.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When the router is configured with Level 1 routing only, this router learns about destinations only inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.
When the router is configured with Level 2 routing only, this router is part of the backbone, and does not communicate with Level 1 routers in its own area.
The router has one link-state packet database (LSDB) for destinations inside the area (Level 1 routing) and runs a shortest path first (SPF) calculation to discover the area topology. It also has another LSDB with link-state packets (LSPs) of all other backbone (Level 2) routers, and runs another SPF calculation to discover the topology of the backbone and the existence of all other areas.
We highly recommend that you configure the type of an IS-IS routing process to establish the proper level of adjacencies. If there is only one area in the network, there is no need to run both Level 1 and Level 2 routing algorithms.
Task ID
Examples
The following example shows how to specify that the router is part of the backbone and that it does not communicate with Level 1-only routers:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# is-type level-2-onlylog adjacency changes (IS-IS)
To cause an IS-IS instance to generate a log message when an Intermediate System-to-Intermediate System (IS-IS) adjacency changes state (up or down), use the log adjacency changes command in router configuration mode. To restore the default value, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the log adjacency changes command to monitor IS-IS adjacency state changes; it may be very useful when you are monitoring large networks. Messages are logged using the system error message facility. Messages can be in either of two forms:
%ISIS-4-ADJCHANGE: Adjacency to 0001.0000.0008 (Gi 0/2/1/0) (L2) Up, new adjacency %ISIS-4-ADJCHANGE: Adjacency to router-gsr8 (Gi /2/1/0) (L1) Down, Holdtime expiredUsing the no form of the command removes the specified command from the configuration file and restores the system to its default condition with respect to the command.
Task ID
log pdu drops
To log Intermediate System-to-Intermediate System (IS-IS) protocol data units (PDUs) that are dropped, use the log pdu drops command in router configuration mode. To disable this function, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the log pdu drops command to monitor a network when IS-IS PDUs are suspected of being dropped. The reason for the PDU being dropped and current PDU drop statistics are recorded.
The following are examples of PDU logging output:
%ISIS-4-ERR_IIH_INPUT_Q_OVERFLOW: IIH input queue overflow: 86 total drops; 19 IIH drops, 44 LSP drops, 23 SNP drops %ISIS-4-ERR_LSP_INPUT_Q_OVERFLOW: LSP input queue overflow: 17 total drops; 9 IIH drops, 3 LSP drops, 5 SNP dropsTask ID
lsp fast-flood threshold
To configure the link-state packet (LSP) fast-flood threshold, use the lsp fast-flood threshold command in interface configuration mode. To restore the default value, use the no form of this command.
lsp fast-flood threshold lsp-number [ level { 1 | 2 } ]
no lsp fast-flood threshold [lsp-number] [ level { 1 | 2 } ]
Syntax Description
lsp-number
Number of LSPs to send back to back. Range is 1 to 4294967295.
level { 1 | 2 }
(Optional) Specifies the LSP threshold for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the lsp fast-flood threshold command to accelerate convergence of LSP database. LSPs are sent back-to-back over an interface up to the specified limit. Past the limit, LSPs are sent out in the next batch window as determined by LSP pacing interval.
Duration of back-to-back window = LSP interval * LSP fast-flood threshold limit.
Task ID
Examples
The following example shows how to configure the LSP threshold:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# lsp fast-flood threshold 234 level 1lsp-gen-interval
To customize IS-IS throttling of link-state packet (LSP) generation, use the lsp-gen-interval command in router configuration mode. To restore the default value, use the no form of this command.
lsp-gen-interval [ initial-wait initial ] [ secondary-wait secondary ] [ maximum-wait maximum ] [ level { 1 | 2 } ]
no lsp-gen-interval [ [ initial-wait initial ] [ secondary-wait secondary ] [ maximum-wait maximum ] ] [ level { 1 | 2 } ]
Syntax Description
initial-wait initial
Specifies the initial LSP generation delay (in milliseconds). Range is 0 to 120000 milliseconds.
secondary-wait secondary
Specifies the hold time between the first and second LSP generation (in milliseconds). Range is 1 to 120000 milliseconds.
maximum-wait maximum
Specifies the maximum interval (in milliseconds) between two consecutive occurrences of an LSP being generated. Range is 1 to 120000 milliseconds.
level { 1 | 2 }
(Optional) Specifies the LSP time interval for Level 1 or Level 2 independently.
Command Default
initial-wait initial : 50 milliseconds
secondary-wait secondary : 200 milliseconds
maximum-wait maximum : 5000 milliseconds
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
During prolonged periods of network instability, repeated recalculation of LSPs can cause increased CPU load on the local router. Further, the flooding of these recalculated LSPs to the other Intermediate Systems in the network causes increased traffic and can result in other routers having to spend more time running route calculations.
Use the lsp-gen-interval command to reduce the rate of LSP generation during periods of instability in the network. This command can help to reduce CPU load on the router and to reduce the number of LSP transmissions to its IS-IS neighbors.
Task ID
Examples
The following example shows how to set the maximum interval between two consecutive occurrences of an LSP to 15 milliseconds and the initial LSP generation delta to 5 milliseconds:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# lsp-gen-interval maximum-wait 15 initial-wait 5lsp-interval
To configure the amount of time between consecutive link-state packets (LSPs) sent on an Intermediate System-to-Intermediate System (IS-IS) interface, use the lsp-interval command in interface configuration mode. To restore the default value, use the no form of this command.
Syntax Description
milliseconds
Time delay (in milliseconds) between successive LSPs. Range is 1 to 4294967295.
level { 1 | 2 }
(Optional) Configures the LSP time delay for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to cause the system to send LSPs every 100 milliseconds (10 packets per second) on Level 1 and Level 2:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet /2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# lsp-interval 100lsp-mtu
To set the maximum transmission unit (MTU) size of Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs), use the lsp-mtu command in router configuration mode. To restore the default, use the no form of this command.
Syntax Description
bytes
Maximum packet size in bytes. The number of bytes must be less than or equal to the smallest MTU of any link in the network. Range is 128 to 4352 bytes.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Under normal conditions, the default MTU size should be sufficient. However, if the MTU size of a link is less than 1500 bytes, the LSP MTU size must be lowered accordingly on each router in the network. If this action is not taken, routing becomes unpredictable.
This guideline applies to all Cisco networking devices in a network. If any link in the network has a reduced MTU size, all devices must be changed, not just the devices directly connected to the link.
Note
Do not set the lsp-mtu command (network layer) to a value greater than the link MTU size that is set with the mtu command (physical layer).
To be certain about a link MTU size, use the show isis interface command to display the value.
Task ID
Examples
The following example shows how to set the MTU size to 1300 bytes:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# lsp-mtu 1300lsp-password
To configure the link-state packet (LSP) authentication password, use the lsp-password command in router configuration mode. To remove the lsp-password command from the configuration file and disable link-state packet authentication, use the no form of this command.
lsp-password [ [ hmac-md5 | text ] [ clear | encrypted ] password | keychain keychain-name ] [ level { 1 | 2 } ] [send-only] [ snp send-only ]
no lsp-password [ [ hmac-md5 | text ] [ clear | encrypted ] password | keychain keychain-name ] [ level { 1 | 2 } ] [send-only] [ snp send-only ]
Syntax Description
hmac-md5
Specifies that the password uses HMAC-MD5 authentication.
text
Specifies that the password uses clear text password authentication.
clear
Specifies that the password be unencrypted.
encrypted
Specifies that the password be encrypted using a two-way algorithm.
password
Authentication password you assign.
keychain
(Optional) Specifies a keychain.
keychain-name
Name of the keychain.
level { 1 | 2 }
(Optional) Specifies the password for Level 1 or Level 2 independently.
send-only
(Optional) Adds passwords to LSP and sequence number protocol (SNP) data units when they are sent. Does not check for authentication in received LSPs or sequence number PDUs (SNPs).
snp send-only
(Optional) Adds passwords to SNP data units when they are sent. Does not check for authentication in received SNPs. This option is available when the text keyword is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When a text password is configured, it is exchanged as clear text. Therefore, the lsp-password command provides limited security.
When an HMAC-MD5 password is configured, the password is never sent over the network and is instead used to calculate a cryptographic checksum to ensure the integrity of the exchanged data.
The recommended password configuration is that both incoming and outgoing SNPs be authenticated.
Note
To disable SNP password checking, the snp send-only keywords must be specified in the lsp-password command.
To configure an additional password, use the lsp-password accept command.
Specify a key chain to enable key chain authentication between two IS-IS peers. Use the keychain keychain-name keyword and argument to implement hitless key rollover for authentication.
Task ID
Examples
The following example shows how to configure separate Level 1 and Level 2 LSP and SNP passwords, one with HMAC-MD5 authentication and encryption and one with clear text password authentication and no encryption:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# lsp-password hmac-md5 clear password1 level 1 RP/0/RP0/CPU0:router(config-isis)# lsp-password text clear password2 level 2lsp-password accept
To configure an additional link-state packet (LSP) authentication password, use the lsp-password accept command in router configuration mode. To remove the lsp-password accept command from the configuration file and restore the system to its default condition, use the no form of this command.
lsp-password accept { clear | encrypted } password [ level { 1 | 2 } ]
no lsp-password accept [ { clear | encrypted } password [ level { 1 | 2 } ] ]
Syntax Description
clear
Specifies that the password be unencrypted.
encrypted
Specifies that the password be encrypted using a two-way algorithm.
password
Authentication password you assign.
level { 1 | 2 }
(Optional) Specifies the password for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The lsp-password accept command adds an additional password for use when the system validates incoming LSPs and sequence number PDUs (SNPs). An LSP password must be configured using the lsp-password command before an accept password can be configured for the corresponding level.
Task ID
lsp-refresh-interval
To set the time between regeneration of link-state packets (LSPs) that contain different sequence numbers, use the lsp-refresh-interval command in router configuration mode. To restore the default refresh interval, use the no form of this command.
lsp-refresh-interval seconds [ level { 1 | 2 } ]
no lsp-refresh-interval [ seconds [ level { 1 | 2 } ] ]
Syntax Description
seconds
Refresh interval (in seconds). Range is 1 to 65535 seconds.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command Default
seconds : 900 seconds (15 minutes)
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The refresh interval determines the rate at which the software periodically sends the route topology information that it originates. This behavior is done to keep the information from becoming too old. By default, the refresh interval is 900 seconds (15 minutes).
LSPs must be refreshed periodically before their lifetimes expire. The refresh interval must be less than the LSP lifetime specified with this router command. Reducing the refresh interval reduces the amount of time that undetected link-state database corruption can persist at the cost of increased link utilization. (This event is extremely unlikely, however, because there are other safeguards against corruption.) Increasing the interval reduces the link utilization caused by the flooding of refreshed packets (although this utilization is very small).
Task ID
Examples
The following example shows how to change the LSP refresh interval to 10,800 seconds (3 hours):
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# lsp-refresh-interval 10800maximum-paths (IS-IS)
To configure the maximum number of parallel routes that an IP routing protocol will install into the routing table, use the maximum-paths command in address family configuration mode. To remove the maximum-paths command from the configuration file and restore the system to its default condition with respect to the routing protocol, use the no form of this command.
Syntax Description
maximum
Maximum number of parallel routes that IS-IS can install in a routing table. Range is 1 to 32
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
maximum-redistributed-prefixes (IS-IS)
To specify an upper limit on the number of redistributed prefixes (subject to summarization) that the Intermediate System-to-Intermediate System (IS-IS) protocol advertises, use the maximum-redistributed-prefixes command in address family mode. To disable this feature, use the no form of this command.
maximum-redistributed-prefixes maximum [ level { 1 | 2 } ]
no maximum-redistributed-prefixes [ maximum [ level { 1 | 2 } ] ]
Syntax Description
maximum
Maximum number of redistributed prefixes advertised. Range is 1 to 28000.
level { 1 | 2 }
(Optional) Specifies maximum prefixes for Level 1 or Level 2.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the maximum-redistributed-prefixes command to prevent a misconfiguration from resulting in redistribution of excess prefixes. If IS-IS encounters more than the maximum number of prefixes, it sets a bi-state alarm. If the number of to-be-redistributed prefixes drops back to the maximum or lower—either through reconfiguration or a change in the redistribution source—IS-IS clears the alarm.
Task ID
max-lsp-lifetime
To set the maximum time that link-state packets (LSPs) persist without being refreshed, use the max-lsp-lifetime command in router configuration mode. To restore the default time, use the no form of this command.
Syntax Description
seconds
Lifetime (in seconds) of the LSP. Range from 1 to 65535 seconds.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command Default
seconds : 1200 seconds (20 minutes)
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
You might need to adjust the maximum LSP lifetime if you change the LSP refresh interval with the lsp-refresh-interval command. The maximum LSP lifetime must be greater than the LSP refresh interval.
Task ID
mesh-group (IS-IS)
To optimize link-state packet (LSP) flooding in highly meshed networks, use the mesh-group command in interface configuration mode. To remove a subinterface from a mesh group, use the no form of this command.
Syntax Description
number
Number identifying the mesh group of which this interface is a member. Range is 1 to 4294967295.
blocked
Specifies that no LSP flooding takes place on this interface.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
LSPs first received on subinterfaces that are not part of a mesh group are flooded to all other subinterfaces in the usual way.
LSPs first received on subinterfaces that are part of a mesh group are flooded to all interfaces except those in the same mesh group. If the blocked keyword is configured on a subinterface, then a newly received LSP is not flooded out over that interface.
To minimize the possibility of incomplete flooding, you should allow unrestricted flooding over at least a minimal set of links in the mesh. Selecting the smallest set of logical links that covers all physical paths results in very low flooding, but less robustness. Ideally you should select only enough links to ensure that LSP flooding is not detrimental to scaling performance, but enough links to ensure that under most failure scenarios, no router is logically disconnected from the rest of the network. In other words, blocking flooding on all links permits the best scaling performance, but there is no flooding. Permitting flooding on all links results in very poor scaling performance.
Note
See RFC 2973 for details about the mesh group specification.
Task ID
Examples
In the following example, six interfaces are configured in three mesh groups. LSPs received are handled as follows:
- LSPs first received by GigabitEthernet interface 0/1/0/0 are flooded to all interfaces except GigabitEthernet 0/1/0/1 (which is part of the same mesh group) and GigabitEthernet 0/3/0/0 (which is blocked).
- LSPs first received by GigabitEthernet 0/2/0/1 are flooded to all interfaces except GigabitEthernet 0/2/0/0 (which is part of the same mesh group) and GigabitEthernet 0/3/0/0 (which is blocked).
- LSPs first received by GigabitEthernet 0/3/0/0 are not ignored, but flooded as usual to all interfaces.
- LSPs received first through GigabitEthernet 0/3/0/1 are flooded to all interfaces, except GigabitEthernet 0/3/0/0 (which is blocked).
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/0 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group 10 RP/0/RP0/CPU0:router(config-isis-if)# exit RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group 10 RP/0/RP0/CPU0:router(config-isis-if)# exit RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/0 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group 11 RP/0/RP0/CPU0:router(config-isis-if)# exit RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group 11 RP/0/RP0/CPU0:router(config-isis-if)# exit RP/0/RP0/CPU0:routerconfig-isis)# interface GigabitEthernet 0/3/0/1 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group 12 RP/0/RP0/CPU0:router(config-isis-if)# exit RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# mesh-group blockedmetric (IS-IS)
To configure the metric for an Intermediate System-to-Intermediate System (IS-IS) interface, use the metric command in address family or interface address family configuration mode. To restore the default metric value, use the no form of this command.
metric { default-metric | maximum } [ level { 1 | 2 } ]
no metric [ { default-metric | maximum } [ level { 1 | 2 } ] ]
Syntax Description
default-metric
Note Setting the default metric under address family results in setting the same metric for all interfaces that is associated with the address family. Setting a metric value under an interface overrides the default metric
maximum
Specifies maximum wide metric. All routers exclude this link from their shortest path first (SPF).
level { 1 | 2 }
(Optional) Specifies the SPF calculation for Level 1 or Level 2 independently.
Command Default
default-metric : Default is 10.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Specifying the level keyword resets the metric only for the specified level. We highly recommend that you configure metrics on all interfaces.
Set the default metric under address family to set the same metric for all interfaces that is associated with the address family. Set a metric value under an interface to override the default metric.
We highly recommend that you configure metrics on all interfaces.
Metrics of more than 63 cannot be used with narrow metric style.
Task ID
Examples
The following example shows how to configure Packet-over-SONET/SDH 0/1/0/1 interface with a default link-state metric cost of 15 for Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet /1/0/1 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# metric 15 level 1The following example shows how to configure a metric cost of 15 for all interfaces under address family IPv4 unicast for level 2:RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# metric 15 level 2metric-style narrow
To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept old-style type, length, and value (TLV) objects, use the metric-style narrow command in address family configuration mode. To remove the metric-style narrow command from the configuration file and restore the system to its default condition, use the no form of this command.
metric-style narrow [transition] [ level { 1 | 2 } ]
no metric-style narrow [transition] [ level { 1 | 2 } ]
Syntax Description
transition
(Optional) Instructs the router to generate and accept both old-style and new-style TLV objects. It generates only old-style TLV objects.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command Default
Old-style TLVs are generated.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
IS-IS traffic engineering extensions include new-style TLV objects with wider metric fields than old-style TLV objects. By default, the router generates old-style TLV objects only. To perform Multiprotocol Label Switching traffic engineering (MPLS TE), a router must generate new-style TLV objects.
Task ID
Examples
The following example shows how to configure the router to generate and accept only old-style TLV objects on router Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# metric-style narrow level 1metric-style transition
To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept both old-style and new-style type, length, and value (TLV) objects, use the metric-style transition command in address family configuration mode. To remove the metric-style transition command from the configuration file and restore the system to its default condition, use the no form of this command.
Syntax Description
transition
Instructs the router to generate and accept both old-style and new-style TLV objects.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command Default
Old-style TLVs are generated, if this command is not configured.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
IS-IS traffic engineering extensions include new-style TLV objects which have wider metric fields than old-style TLV objects. By default, the router generates old-style TLV objects only. To perform Multiprotocol Label Switching traffic engineering (MPLS TE), a router needs to generate new-style TLV objects.
Task ID
Examples
The following example shows how to configure the router to generate and accept both old-style and new-style TLV objects on Level 2:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# metric-style transition level 2metric-style wide
To configure the Intermediate System-to-Intermediate System (IS-IS) software to generate and accept only new-style type, length, and value (TLV) objects, use the metric-style wide command in address family configuration mode. To remove the metric-style wide command from the configuration file and restore the system to its default condition, use the no form of this command.
metric-style wide [transition] [ level { 1 | 2 } ]
no metric-style wide [transition] [ level { 1 | 2 } ]
Syntax Description
transition
(Optional) Instructs the router to generate and accept both old-style and new-style TLV objects. It generates only new-style TLV objects.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command Default
Old-style TLV lengths are generated, if this command is not configured.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
IS-IS traffic engineering extensions include new-style TLV objects with wider metric fields than old-style TLV objects. If you enter the metric-style wide command, a router generates and accepts only new-style TLV objects. Therefore, the router uses less memory and fewer other resources rather than generating both old-style and new-style TLV objects.
To perform MPLS traffic engineering, a router needs to generate new-style TLV objects.
Note
This discussion of metric styles and transition strategies is oriented toward traffic engineering deployment. Other commands and models might be appropriate if the new-style TLV objects are desired for other reasons. For example, a network may require wider metrics, but might not use traffic engineering.
Task ID
Examples
The following example shows how to configure a router to generate and accept only new-style TLV objects on Level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0//CPU0:router(config-isis-af)# metric-style wide level 1min-lsp-arrivaltime
To control the rate of incoming LSPs (link-state packets) LSPs, use the min-lsp-arrivaltime command in router configuration mode. To remove this function use the no form of this command.
min-lsp-arrivaltime [ initial-wait initial ] [ secondary-wait secondary ] [ maximum-wait maximum ] [ level { 1 | 2 } ]
no min-lsp-arrivaltime [ initial-wait initial ] [ secondary-wait secondary ] [ maximum-wait maximum ] [ level { 1 | 2 } ]
Syntax Description
initial-wait initial
Initial LSP calculation delay (in milliseconds). Range is 0 to 120000.
secondary-wait secondary
Hold time between the first and second LSP calculations (in milliseconds). Range is 0 to 120000.
maximum-wait maximum
Maximum interval (in milliseconds) between two consecutive LSP calculations. Range is 0 to 120000.
level { 1 | 2 }
(Optional) Enables the LSP interval configuration for Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
This command can be used to protect a router against the possible instability of its neighbor's LSPs.
The command parameters are similair to lsp-gen-intervalcommand and neighbors lsp-gen-interval values can be used to set the min-lsp-arrivaltime
Note
The initial-wait of minimum-lsp-arrival has no use in computing maximum counts and maximum window sizes of the LSP arrival time parameter.
Task ID
Examples
The following example shows how to configure min-lsp-arrival time commands:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config)# router isis isp min-lsp-arrivaltime RP/0/RP0/CPU0:router(config)# router isis 1 min- lsp-arrivaltime initial-wait RP/0/RP0/CPU0:router(config)#router isis 1 min-lsp-arrivaltime maximum-wait RP/0/RP0/CPU0:router(config)#router isis 1 min-lsp-arrivaltime secondary-waitmpls ldp auto-config
To enable Label Distribution Protocol (LDP) Interior Gateway Protocol (IGP) interface auto-configuration, use the mpls ldp auto-config command in IPv4 address family configuration mode. To disable LDP IGP auto-configuration, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the mpls ldp auto-config command to automatically configure LDP on a set of interfaces associated with a specified IGP instance. Further, LDP IGP auto-configuration provides a means to block LDP from being enabled on a specified interface. If you do not want an IS-IS interface to have LDP enabled, use the igp auto-config disable command.
Task ID
mpls ldp sync (IS-IS)
To configure Label Distribution Protocol (LDP) IS-IS synchronization, use the mpls ldp sync command in interface address family configuration mode. To disable LDP synchronization, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
MPLS VPN traffic forwarded using LDP labels can be dropped in the following instances:
- A new link is introduced in the network and IS-IS has converged before LDP establishes labels.
- An existing LDP session goes down while IS-IS adjacency is intact over the link.
In both instances, outbound LDP labels are not available for forwarding MPLS traffic. LDP IS-IS synchronization addresses the traffic drop. When the mpls ldp sync command is configured, IS-IS advertises the maximum possible link metric until LDP has converged over the link. The link is less preferred and least used in forwarding MPLS traffic. When LDP establishes the session and exchanges labels, IS-IS advertises the regular metric over the link.
Note
IS-IS advertises the maximum metric –1 (16777214) if wide metrics are configured since the maximum wide metric is specifically used for link exclusion from the shortest path first algorithm (SPF) (RFC 3784). However, the maximum narrow metric is unaffected by this definition.
Task ID
Examples
The following example shows how to enable LDP IS-IS synchronization:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# mpls ldp syncmpls traffic-eng (IS-IS)
To configure a router running the Intermediate System-to-Intermediate System (IS-IS) protocol to flood Multiprotocol Label Switching traffic engineering (MPLS TE) link information into the indicated IS-IS level, use the mpls traffic-eng command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.
mpls traffic-eng { level-1 | level-1-2 | level-2-only }
no mpls traffic-eng [ level-1 | level-1-2 | level-2-only ]
Syntax Description
level-1
Specifies routing level 1.
level-1-2
Specifies routing levels 1 and 2.
level-2-only
Specifies routing level 2.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the mpls traffic-eng command, which is part of the routing protocol tree, to flood link resource information (such as available bandwidth) for appropriately configured links in the link-state packet (LSP) of the router.
Task ID
Examples
The following example shows how to turn on MPLS traffic engineering for IS-IS level 1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# mpls traffic-eng level-1mpls traffic-eng multicast-intact (IS-IS)
To enable multicast-intact for Intermediate System-to-Intermediate System (IS-IS) routes with Protocol-Independent Multicast (PIM) and Multiprotocol Label Switching (MPLS) traffic engineering, use the mpls traffic-eng multicast-intact command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
If Multiprotocol Label Switching Traffic Engineering (MPLS-TE) is configured through the IS-IS routing domain and multicast protocols (like Protocol Independent Multicast [PIM]) are also enabled, then use the mpls traffic-end multicast-intact command to install nontraffic engineering next hops in the Routing Information Base (RIB) for use by multicast. The installation of IP-only next hops is in addition to the installation of the standard set of paths for a prefix, which might be through traffic engineered tunnels.
The mpls traffic-eng multicast-intact command allows PIM to use the native hop-by-hop neighbors even though the unicast routing is using MPLS TE tunnels.
Examples
The following example shows how to enable the multicast-intact feature:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# mpls traffic-engmulticast-intactmpls traffic-eng path-selection ignore overload
To ensure that label switched paths (LSPs) are not disabled when routers have the Intermediate System-to-Intermediate System (IS-IS) overload bit set, use the mpls traffic-eng path-selection ignore overload command in XR Config mode. To disable this override, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When the IS-IS overload bit avoidance feature is activated, which means that they are still available for use label switched paths (LSPs), all nodes with the overload bit set, including the following nodes, are ignored:
Task ID
Examples
The following example shows how to activate IS-IS overload bit avoidance:
RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# mpls traffic-eng path-selection ignore overloadThe following example shows how to deactivate IS-IS overload bit avoidance:
RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# no mpls traffic-eng path-selection ignore overloadmpls traffic-eng router-id (IS-IS)
To specify the Multiprotocol Label Switching traffic engineering (MPLS TE) router identifier for the node, use the mpls traffic-eng router-id command in IPv4 address family configuration mode. To disable this feature, use the no form of this command.
Syntax Description
ip-address
IP address in four-part, dotted-decimal notation.
type
Interface type. For more information, use the question mark (?) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark (?) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The identifier of the router acts as a stable IP address for the traffic engineering configuration. This IP address is flooded to all nodes. For all traffic engineering tunnels originating at other nodes and ending at this node, you must set the tunnel destination to the traffic engineering router ID of the destination node, because that is the address used by the traffic engineering topology database at the tunnel head for its path calculation.
Note
We recommend that loopback interfaces be used for MPLS TE, because they are more stable than physical interfaces.
Task ID
Examples
The following example shows how to specify the traffic engineering router identifier as the IP address associated with loopback interface 0:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# mpls traffic-eng router-id Loopback0mpls traffic-eng srlg (IS-IS)
To configure Shared Risk Link Group (SRLG) membership of a link, use the mpls traffic-eng srlg command in XR Config mode. To disable this feature, use the no form of this command.
mpls traffic-eng [ type interface-path-id ] srlg number
no mpls traffic-eng [ type interface-path-id ] srlg number
Syntax Description
number
SRLG membership number. Range is 0 to 4294967295.
type
Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Physical interface or virtual interface.
Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to configure an SRLG with 10 member links:
RP/0/RP0/CPU0:router(config)#mpls traffic-eng interface gigabitEthernet 0/1/0/1 RP/0/RP0/CPU0:router(config-mpls-te-if)#srlg 10net
To configure an Intermediate System-to-Intermediate System (IS-IS) network entity title (NET) for the routing instance, use the net command in router configuration mode. To remove the net command from the configuration file and restore the system to its default condition, use the no form of this command.
Syntax Description
network-entity-title
NET that specifies the area address and the system ID for an ISIS routing process.
Command Default
No NET is configured. The IS-IS instance is not operational, because a NET is mandatory.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Under most circumstances, one and only one NET should be configured.
A NET is a network service access point (NSAP) where the last byte is always 0. On a Cisco router running IS-IS, a NET can be 8 to 20 bytes in length. The last byte is always the n-selector and must be 0. The n-selector indicates to which transport entity the packet is sent. An n-selector of 0 indicates no transport entity and means that the packet is for the routing software of the system.
The six bytes directly preceding the n-selector are the system ID. The system ID length is a fixed size and cannot be changed. The system ID must be unique throughout each area (Level 1) and throughout the backbone (Level 2).
All bytes preceding the system ID are the area ID.
A maximum of three NETs for each router is allowed. In rare circumstances, it is possible to configure two or three NETs. In such a case, the area this router is in has three area addresses. Only one area still exists, but it has more area addresses.
Configuring multiple NETs can be temporarily useful in network reconfiguration in which multiple areas are merged, or in which one area is split into more areas. Multiple area addresses enable you to renumber an area individually as needed.
Task ID
Examples
The following example shows how to configure a router with NET area ID 47.0004.004d.0001 and system ID 0001.0c11.1110:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# net 47.0004.004d.0001.0001.0c11.1110.00nsf (IS-IS)
To enable nonstop forwarding (NSF) on the next restart, use the nsf command in router configuration mode. To restore the default setting, use the no form of this command.
Syntax Description
cisco
Specifies Cisco-proprietary NSF restart.
ietf
Specifies Internet Engineering Task Force (IETF) NSF restart.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
NSF allows an Intermediate System-to-Intermediate System (IS-IS) instance to restart using checkpointed adjacency and link-state packet (LSP) information, and to perform restart with no impact on its neighbor routers. In other words, there is no impact on other routers in the network due to the destruction and recreation of adjacencies and the system LSP.
Task ID
Examples
The following example shows how to enable Cisco proprietary NSF:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# nsf cisconsf interface-expires
To configure the number of resends of an acknowledged nonstop forwarding (NSF)-restart acknowledgment, use the nsf interface-expires command in router configuration mode. To restore the default value, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When a hello packet sent with the NSF restart flag set is not acknowledged, it is re-sent. Use the nsf interface-expires command to control the number of times the NSF hello is re-sent. When this limit is reached on an interface, any neighbor previously known on that interface is assumed to be down and the initial shortest path first (SPF) calculation is permitted, provided that all other necessary conditions are met.
The total time period available for adjacency reestablishment (interface-timer * interface-expires) should be greater than the expected total NSF restart time.
The nsf interface-expires command applies only to Internet Engineering Task Force (IETF)-style NSF. It has no effect if Cisco-proprietary NSF is configured.
Task ID
Examples
The following example shows how to allow only one retry attempt on each interface if an IETF NSF restart signal is not acknowledged:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# nsf ietf RP/0/RP0/CPU0:router(config-isis)# nsf interface-expires 1nsf interface-timer
To configure the time interval after which an unacknowledged Internet Engineering Task Force (IETF) nonstop forwarding (NSF) restart attempt is repeated, use the nsf interface-timer command in router configuration mode. To restore the default value, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
When the IETF NSF restart process begins, hello packets send an NSF restart flag that must be acknowledged by the neighbors of the router. Use the nsf interface-timer command to control the restart time interval after the hello packet is re-sent. The restart time interval need not match the hello interval.
The nsf interface-timer command applies only to IETF-style NSF. It has no effect if Cisco proprietary NSF is configured.
Task ID
Examples
The following example shows how to ensure that a hello packet with the NSF restart flag set is sent again every 5 seconds until the flag is acknowledged:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# nsf ietf RP/0/RP0/CPU0:router(config-isis)# nsf interface-timer 5nsf lifetime (IS-IS)
To configure the maximum route lifetime following a nonstop forwarding (NSF) restart, use the nsf lifetime command in router configuration mode. To restore the default value, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the nsf lifetime command to set the maximum available time for the reacquisition of checkpointed adjacencies and link-state packets (LSPs) during a Cisco proprietary NSF restart. LSPs and adjacencies not recovered during this time period are abandoned, thus causing changes to the network topology.
Task ID
passive (IS-IS)
To suppress Intermediate System-to-Intermediate System (IS-IS) packets from being transmitted to the interface and received packets from being processed on the interface, use the passive command in interface configuration mode. To restore IS-IS packets coming to an interface, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to configure the router to suppress IS-IS packets on GigabitEthernet interface 0/1/0/1:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/1/0/1 RP/0/RP0/CPU0:router(config-isis-if)# passivepoint-to-point
To configure a network of only two networking devices that use broadcast media and the integrated Intermediate System-to-Intermediate System (IS-IS) routing protocol to function as a point-to-point link instead of a broadcast link, use the point-to-point command in interface configuration mode. To disable the point-to-point usage, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the point-to-point command only on broadcast media in a network with two networking devices. The command causes the system to issue packets point-to-point rather than as broadcasts. Configure the command on both networking devices in the network.
Task ID
priority (IS-IS)
To configure the priority of designated routers, use the priority command in interface configuration mode. To reset the default priority, use the no form of this command.
Syntax Description
value
Priority of a router. Range is 0 to 127.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Priorities can be configured for Level 1 and Level 2 independently. Specifying Level 1 or Level 2 resets priority only for Level 1 or Level 2 routing, respectively. Specifying no level allows you to configure all levels.
The priority is used to determine which router on a LAN is the designated router or Designated Intermediate System (DIS). The priorities are advertised in the hello packets. The router with the highest priority becomes the DIS.
In the Intermediate System-to-Intermediate System (IS-IS) protocol, there is no backup designated router. Setting the priority to 0 lowers the chance of this system becoming the DIS, but does not prevent it. If a router with a higher priority comes online, it takes over the role from the current DIS. For equal priorities, the higher MAC address breaks the tie.
Task ID
Examples
The following example shows how to give Level 1 routing priority by setting the priority level to 80. This router is now more likely to become the DIS.
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface TenGigE0/6/0/0 RP/0/RP0/CPU0:router(config-isis-if)# priority 80 level 1propagate level
To propagate routes from one Intermediate System-to-Intermediate System (IS-IS) level into another level, use the propagate level command in address family configuration mode. To disable propagation, use the no form of this command.
propagate level { 1 | 2 } into level { 1 | 2 } route-policy route-policy-name
no propagate level { 1 | 2 } into level { 1 | 2 }
Syntax Description
level { 1 | 2 }
Propagates from routing Level 1 or Level 2 routes.
into
Propagates from Level 1 or Level 2 routes into Level 1 or Level 2 routes.
route-policy route-policy-name
Specifies a configured route policy.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
In general, route propagation from Level 1 to Level 2 is automatic. You might want to use this command to better control which Level 1 routes can be propagated into Level 2.
Propagating Level 2 routes into Level 1 is called route leaking. Route leaking is disabled by default. That is, Level 2 routes are not automatically included in Level 1 link-state packets (LSPs). If you want to leak Level 2 routes into Level 1, you must enable that behavior by using this command.
Propagation from Level 1 into Level 1 and from Level 2 into Level 2 is not allowed.
Task ID
Examples
The following example shows how to redistribute Level 2 routes to Level 1:
RP/0/RP0/CPU0:router(config)# ipv4 access-list 101 permit ip 10.0.0.0 255.0.0.0 10.1.0.1 0.255.255.255 RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# net 49.1234.2222.2222.2222.00 RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# propagate level 2 into level 1 route-policy policy_aredistribute (IS-IS)
To redistribute routes from one routing protocol into Intermediate System-to-Intermediate System (IS-IS), use the redistribute command in address family configuration mode. To remove the redistribute command from the configuration file and restore the system to its default condition in which the software does not redistribute routes, use the no form of this command.
Border Gateway Protocol (BGP)
redistribute bgp process-id [ level-1 | level-2 | level-1-2 ] [ metric metric-value ] [ metric-type { internal | external | rib-metric-as-external | rib-metric-as-internal } ] [ route-policy route-policy-name ]
no redistribute
Connected Routes
redistribute connected [ level-1 | level-2 | level-1-2 ] [ metric metric-value ] [ metric-type { internal | external | rib-metric-as-external | rib-metric-as-internal } ] [ route-policy route-policy-name ]
no redistribute
Intermediate System-to-Intermediate System (IS-IS)
redistribute isis process-id [ level-1 | level-2 | level-1-2 ] [ metric metric-value ] [ metric-type { internal | external | rib-metric-as-external | rib-metric-as-internal } ] [ route-policy route-policy-name ]
no redistribute
Open Shortest Path First (OSPF)
redistribute ospf process-id [ level-1 | level-2 | level-1-2 ] [ match { external [ 1 | 2 ] | internal | nssa-external [ 1 | 2 ] } ] [ metric metric-value ] [ metric-type { internal | external | rib-metric-as-external | rib-metric-as-internal } ] [ route-policy route-policy-name ]
no redistribute
Open Shortest Path First Version 3 (OSPFv3)
redistribute ospfv3 process-id [ level-1 | level-2 | level-1-2 ] [ match { external [ 1 | 2 ] | internal | nssa-external [ 1 | 2 ] } ] [ metric metric-value ] [ metric-type { internal | external | rib-metric-as-external | rib-metric-as-internal } ] [ route-policy route-policy-name ]
no redistribute
Static Routes
redistribute static [ level-1 | level-2 | level-1-2 ] [ metric metric-value ] [ metric-type { { internal | external | rib-metric-as-external } | } ] [ route-policy route-policy-name ]
no redistribute
Syntax Description
Command Default
Level 2 is configured if no level is specified.
metric-type: internal
match : If no match keyword is specified, all OSPF routes are redistributed.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Note
When redistributing routes (into IS-IS) using both command keywords for setting or matching of attributes and a route policy, the routes are run through the route policy first, followed by the keyword matching and setting.
Use the redistribute command to control the redistribution of routes between separate IS-IS instances. To control the propagation of routes between the levels of a single IS-IS instance, use the propagate level command.
Only IPv4 OSPF addresses can be redistributed into IS-IS IPv4 address families.
Task ID
Examples
In this example, IS-IS instance isp_A readvertises all of the routes of IS-IS instance isp_B in Level 2 LSP. Note that the level-2 keyword affects which levels instance isp_A advertises the routes in and has no impact on which routes from instance isp_B are advertised. (Any Level 1 routes from IS-IS instance isp_B are included in the redistribution.
RP/0//CPU0:router(config)# router isis isp_A RP/0//CPU0:router(config-isis)# net 49.1234.2222.2222.2222.00 RP/0//CPU0:router(config-isis)# address-family ipv4 unicast RP/0//CPU0:router(config-isis-af)# redistribute isis isp_B level-2 ! RP/0//CPU0:router(config)# router isis isp_B RP/0//CPU0:router(config-isis)# is-type level 1 RP/0//CPU0:router(config-isis)# net 49.4567.2222.2222.2222.00 RP/0//CPU0:router(config-isis)# address-family ipv4 unicastretransmit-interval (IS-IS)
To configure the amount of time between retransmission of each Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) on a point-to-point link, use the retransmit-interval command in interface configuration mode. To restore the default value, use the no form of this command.
retransmit-interval seconds [ level { 1 | 2 } ]
no retransmit-interval [ seconds [ level { 1 | 2 } ] ]
Syntax Description
seconds
Time (in seconds) between consecutive retransmissions of each LSP. It is an integer that should be greater than the expected round-trip delay between any two networking devices on the attached network. Range is 0 to 65535 seconds.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The retransmit-interval command has no effect on LAN (multipoint) interfaces. On point-to-point links, the value can be increased to enhance network stability.
Because retransmissions occur only when LSPs are dropped, setting this command to a higher value has little effect on reconvergence. The more neighbors networking devices have, and the more paths over which LSPs can be flooded, the higher this value can be made.
Task ID
Examples
The following example shows how to configure GigabitEthernet interface 0/2/0/1 for retransmission of IS-IS LSPs every 60 seconds for a large serial line:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# retransmit-interval 60retransmit-throttle-interval
To configure minimum interval between retransmissions of different Intermediate System-to-Intermediate System (IS-IS) link-state packets (LSPs) on a point-to-point interface, use the retransmit-throttle-interval command in interface configuration mode. To remove the command from the configuration file and restore the system to its default condition, use the no form of this command.
retransmit-throttle-interval milliseconds [ level { 1 | 2 } ]
no retransmit-throttle-interval [ milliseconds [ level { 1 | 2 } ] ]
Syntax Description
milliseconds
Minimum delay (in milliseconds) between LSP retransmissions on the interface. Range is 0 to 65535.
level { 1 | 2 }
(Optional) Specifies routing Level 1 or Level 2 independently.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the retransmit-throttle-interval command to define the minimum period of time that must elapse between retransmitting any two consecutive LSPs on an interface. The retransmit-throttle-interval command may be useful in very large networks with many LSPs and many interfaces as a way of controlling LSP retransmission traffic. This command controls the rate at which LSPs can be re-sent on the interface.
Task ID
Examples
The following example shows how to configure GigabitEthernet interface 0/2/0/1 to limit the rate of LSP retransmissions to one every 300 milliseconds:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/2/0/1 RP/0/RP0/CPU0:router(config-isis-if)# retransmit-throttle-interval 300router isis
To enable the Intermediate System-to-Intermediate System (IS-IS) routing protocol and to specify an IS-IS instance, use the router isis command in XR Config mode. To disable IS-IS routing, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the router isis command to create an IS-IS routing process. An appropriate network entity title (NET) must be configured to specify the address of the area (Level 1) and system ID of the router. Routing must be enabled on one or more interfaces before adjacencies may be established and dynamic routing is possible.
Multiple IS-IS processes can be configured. Up to eight processes are configurable. A maximum of five IS-IS instances on a system are supported.
Task ID
set-attached-bit
To configure an Intermediate System-to-Intermediate System (IS-IS) instance with an attached bit in the Level 1 link-state packet (LSP), use the set-attached-bit command in address family configuration mode. To remove the set-attached-bit command from the configuration file and restore the system to its default condition, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the set-attached bit command to set an IS-IS instance with an attached bit in the Level 1 LSP that allows another IS-IS instance to redistribute Level 2 topology. The attached bit is used when the Level 2 connectivity from another IS-IS instance is advertised by the Level 1 attached bit.
Cisco IOS XR software does not support multiple Level 1 areas in a single IS-IS routing instance. But the equivalent functionality is achieved by redistribution of routes between two IS-IS instances by using the redistribute (IS-IS) command.
The attached bit is configured for a specific address family only if the single-topology command is not configured.
Note
If connectivity for the Level 2 instance is lost, the attached bit in the Level 1 instance LSP continues sending traffic to the Level 2 instance and causes the traffic to be dropped.
Task ID
Examples
The following example shows how to set the attached bit for a Level 1 instance that allows the Level 2 instance to redistribute routes from the Level 1 instance:
RP/0/RP0/CPU0:router(config)# router isis 1 RP/0/RP0/CPU0:router(config-isis)# net 49.0001.0001.0001.0001.00 RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# redistribute isis 2 level 2 ! RP/0/RP0/CPU0:router(config-isis-af)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-af-if)# address-family ipv4 unicast ! ! RP/0/RP0/CPU0:router(config)# router isis 2 RP/0/RP0/CPU0:router(config-isis)# is-type level-1 RP/0/RP0/CPU0:router(config-isis)# net 49.0002.0001.0001.0002.00 RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# -attachedbit send always- ! RP/0/RP0/CPU0:routerfig-isis-af)# interface GigabitEthernet 0/1/0/0 RP/0/RP0/CPU0:router(config-isis-af-if)# address-family ipv4 unicastset-overload-bit
To configure the router to signal other routers not to use it as an intermediate hop in their shortest path first (SPF) calculations, use the set-overload-bit command in router configuration mode. To remove the designation, use the no form of this command.
set-overload-bit [ on-startup { delay | wait-for-bgp } ] [ level { 1 | 2 } ] [ advertise { external | interlevel } ]
no set-overload-bit [ on-startup { delay | wait-for-bgp } ] [ level { 1 | 2 } ]
Syntax Description
on-startup
(Optional) Sets the overload bit only temporarily after reboot.
delay
(Optional) Time (in seconds) to advertise when the router is overloaded after reboot. Range is 5 to 86400 seconds (86400 seconds = 1 day).
wait-for-bgp
(Optional) Sets the overload bit on startup until the Border Gateway Protocol (BGP) signals converge or time out.
level { 1 | 2 }
(Optional) Specifies the overload bit for Level 1 or Level 2 independently.
Command Default
The overload bit is not set.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the set-overload-bit command to force the router to set the overload bit in its nonpseudonode link-state packets (LSPs). Normally the setting of the overload bit is allowed only when a router experiences problems. For example, when a router is experiencing a memory shortage, the reason might be that the link-state database is not complete, resulting in an incomplete or inaccurate routing table. If the overload bit is set in the LSPs of the unreliable router, other routers can ignore the router in their SPF calculations until it has recovered from its problems. The result is that no paths through the unreliable router are seen by other routers in the Intermediate System-to-Intermediate System (IS-IS) area. However, IP prefixes directly connected to this router are still reachable.
The set-overload-bit command can be useful when you want to connect a router to an IS-IS network, but do not want real traffic flowing through it under any circumstances.
Routers with overload bit set are:
Task ID
show isis
The show isis command displays general information about an IS-IS instance and protocol operation. If the instance ID is not specified, the command shows information about all IS-IS instances.Syntax Description
instance instance-id
(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only.
Note The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
For each instance, the first line of output lists the IS-IS instance ID with the following lines identifying the IS-IS system ID, supported levels (level 1, level 2, or level-1-2), configured area addresses, active area addresses, status (enabled or not) and type (Cisco or IETF) of nonstop forwarding (NSF), and the mode in which the last IS-IS process startup occurred.
Next, the status of each configured address family (or just IPv4 unicast if none are configured) is summarized. For each level (level 1 or level 2), the metric style (narrow or wide) generated and accepted is listed along with the status of incremental shortest path first (iSPF) computation (enabled or not). Then redistributed protocols are listed, followed by the administrative distance applied to the redistributed routes.
Finally, the running state (active, passive, or disabled) and configuration state (active or disabled) of each IS-IS interface is listed.
Task ID
Examples
The following is sample output from the show isis command:
RP/0/RP0/CPU0:router# show isis Wed Aug 20 23:54:55.043 PST DST IS-IS Router: lab System Id: 0000.0000.0002 IS Levels: level-2-only Manual area address(es): 49.1122 Routing for area address(es): 49.1122 Non-stop forwarding: Disabled Most recent startup mode: Cold Restart Topologies supported by IS-IS: IPv4 Unicast Level-2 Metric style (generate/accept): Narrow/Narrow Metric: 10 ISPF status: Disabled No protocols redistributed Distance: 115 Interfaces supported by IS-IS: Loopback0 is running passively (passive in configuration) POS0/1/0/2 is running actively (active in configuration) POS0/1/0/3 is running actively (active in configuration
This table describes the significant fields shown in the display.
Table 1 show isis Field DescriptionsField
Description
IS-IS Router
IS-IS instance ID.
System Id
IS-IS system ID.
IS Levels
Supported levels for the instance.
Manual area address(es)
Domain and area.
Routing for area address(es):
Configured area addresses and active area addresses.
Non-stop forwarding
Status (enabled or not) and type (Cisco or IETF) of nonstop forwarding (NSF).
Most recent startup mode
The mode in which the last IS-IS process startup occurred.
Topologies supported by IS-IS
The summary of the status of each configured address family (or just IPv4 unicast if none are configured).
Redistributed protocols
List of redistributed protocols, followed by the administrative distance applied to the redistributed routes.
Metric style (generate/accept)
The status of each configured address family (or just IPv4 unicast if none are configured) is summarized. For each level (level 1 or level 2), the metric style (narrow or wide) generated and accepted is listed along with the status of incremental shortest path first (iSPF) computation (enabled or not).
Interfaces supported by IS-IS
The running state (active, passive, or disabled) and configuration state (active or disabled) of each IS-IS interface.
show isis adjacency
To display Intermediate System-to-Intermediate System (IS-IS) adjacencies, use the show isis adjacency command in XR EXEC mode.
show isis [ instance instance-id ] adjacency [ level { 1 | 2 } ] [ type interface-path-id ] [detail] [ systemid system-id ]
Syntax Description
instance instance-id
(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only.
level { 1 | 2 }
(Optional) Displays the IS-IS adjacencies for Level 1 or Level 2 independently.
type
Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
detail
(Optional) Displays neighbor IP addresses and active topologies.
systemid system-id
(Optional) Displays the information for the specified router only.
Command Default
No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis adjacency command:
RP/0/RP0/CPU0:router# show isis adjacency IS-IS p Level-1 adjacencies: System Id Interface SNPA State Hold Changed NSF BFD 12a4 PO0/1/0/1 *PtoP* Up 23 00:00:06 Capable Init 12a4 Gi0/6/0/2 0004.2893.f2f6 Up 56 00:04:01 Capable Up Total adjacency count: 2 IS-IS p Level-2 adjacencies: System Id Interface SNPA State Hold Changed NSF BFD 12a4 PO0/1/0/1 *PtoP* Up 23 00:00:06 Capable None 12a4 Gi0/6/0/2 0004.2893.f2f6 Up 26 00:00:13 Capable Init Total adjacency count: 2
This table describes the significant fields shown in the display.
Table 2 show isis adjacency Field DescriptionsField
Description
Level-1
Level 1 adjacencies.
Level-2
Level 2 adjacencies.
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or the hostname dynamic disable command has been executed, the 6-octet system ID is used.
Interface
Interface used to reach the neighbor.
SNPA
Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
State
Adjacency state of the neighboring interface. Valid states are Down, Init, and Up.
Holdtime
Hold time of the neighbor.
Changed
Time the neighbor has been up (in hours:minutes:seconds).
NSF
Specifies whether the neighbor can adhere to the IETF-NSF restart mechanism.
BFD
Specifies the Bidirectional Forwarding Detection (BFD) status for the interface. Valid status are
show isis adjacency-log
To display the Intermediate System-to-Intermediate System (IS-IS) adjacency log, use the show isis adjacency-log command in XR EXEC mode.
Syntax Description
level { 1 | 2 }
(Optional) Displays the IS-IS adjacency log for Level 1 or Level 2 independently.
last number
(Optional) Specifies that the output is restricted to the last number of entries. Range is 1 to 100.
first number
(Optional) Specifies that the output is restricted to the first number of entries. Range is 1 to 100.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis adjacency-log command:
RP/0/RP0/CPU0:router# show isis adjacency-log IS-IS 10 Level 1 Adjacency log When System Interface State Details 4d00h 12a1 PO0/5/0/0 d -> i 4d00h 12a1 PO0/5/0/0 i -> u New adjacency IPv4 Unicast Up 4d00h 12a1 Gi0/6/0/0 d -> u New adjacency 4d00h 12a1 Gi0/6/0/0 u -> d Interface state down 3d17h 12a1 Gi0/6/0/0 d -> u New adjacency 3d17h 12a1 Gi0/6/0/0 u -> d Interface state down 01:44:07 12a1 Gi0/6/0/0 d -> u New adjacency IS-IS 10 Level 2 Adjacency log When System Interface State Details 4d00h 12a1 PO0/5/0/0 d -> i 4d00h 12a1 PO0/5/0/0 i -> u New adjacency IPv4 Unicast Up 4d00h 12a1 Gi0/6/0/0 d -> u New adjacency 4d00h 12a1 Gi0/6/0/0 u -> d Interface state down 3d17h 12a1 Gi0/6/0/0 d -> u New adjacency 3d17h 12a1 Gi0/6/0/0 u -> d Interface state down 01:44:07 12a1 Gi0/6/0/0 d -> u New adjacency
This table describes the significant fields shown in the display.
Table 3 show isis adjacency-log Field DescriptionsField
Description
When
Elapsed time (in hh:mm:ss) since the event was logged.
System
System ID of the adjacent router.
Interface
Specific interface involved in the adjacency change.
State
State transition for the logged event.
Details
Description of the adjacency change.
show isis checkpoint adjacency
To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint adjacency database, use the show isis checkpoint adjacency command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the IS-IS checkpoint adjacencies for the specified IS-IS instance only.
Command Default
No instance ID specified displays IS-IS checkpoint adjacencies for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the show isis checkpoint adjacency command to display the checkpointed adjacencies. With this information you can restore the adjacency database during a Cisco proprietary nonstop forwarding (NSF) restart. This command, with the show isis adjacency command, can be used to verify the consistency of the two databases.
Task ID
Examples
The following is sample output from the show isis checkpoint adjacency command:
RP/0/RP0/CPU0:router# show isis checkpoint adjacency Interface Level System ID State Circuit ID Chkpt ID Gi3/0/0/1 1 router-gsr8 Up 0001.0000.0008.04 80011fec Gi0/4/0/1 1 router-gsr9 Up 0001.0000.0006.01 80011fd8 Gi/0/0/1 2 router-gsr8 Up 0001.0000.0008.04 80011fc4
This table describes the significant fields shown in the display.
Table 4 show isis checkpoint adjacency Field DescriptionsField
Description
Interface
Interface used to reach the neighbor.
Level
Lists either routers with Level 1 or Level 2 adjacency configured.
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
State
State of the neighboring interface.
Circuit ID
Unique ID issued to a circuit at its creation.
Chkpt ID
Unique ID issued to the checkpoint at its creation.
show isis checkpoint interface
To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint interfaces, use the show isis checkpoint interface command in XR EXEC mode.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis checkpoint interface command:
RP/0/RP0/CPU0:router# show isis checkpoint interface IS-IS 10 checkpoint interface Interface Index CircNum DIS Areas Chkpt ID PO0/5/0/0 0 0 NONE 80002fe8 Gi0/6/0/0 1 3 L1L2 80002fd0
This table describes the significant fields shown in the display.
Table 5 show isis checkpoint interface Field DescriptionsField
Description
Interface
Interface used to reach the neighbor.
Index
Interface index assigned to an interface upon its creation.
CircNum
Unique ID issued to a circuit internally.
DIS Areas
Designated Intermediate System area.
Chkpt ID
Unique ID issued to the checkpoint at its creation.
show isis checkpoint lsp
To display the Intermediate System-to-Intermediate System (IS-IS) checkpoint link-state packet (LSP) protocol data unit (PDU) identifier database, use the show isis checkpoint lsp command in XR EXEC mode.
Syntax Description
Command Default
No instance ID specified displays IS-IS checkpoint LSPs for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The checkpointed LSPs displayed by this command are used to restore the LSP database during a Cisco-proprietary nonstop forwarding (NSF) restart. The show isis checkpoint lsp command, with the show isis database command, may be used to verify the consistency of the two databases.
Task ID
Examples
The following is sample output from the show isis checkpoint lsp command:
RP/0/RP0/CPU0:router# show isis checkpoint lsp Level LSPID Chkpt ID 1 router-gsr6.00-00 80011f9c 1 router-gsr6.01-00 80011f88 1 router-gsr8.00-00 80011f74 1 router-gsr9.00-00 80011f60 2 router-gsr6.00-00 80011f4c 2 router-gsr6.01-00 80011f38 2 router-gsr8.00-00 80011f24 2 router-gsr9.00-00 80011f10 Total LSP count: 8 (L1: 4, L2 4, local L1: 2, local L2 2)
This table describes the significant fields shown in the display.
Table 6 show isis checkpoint lsp Field DescriptionsField
Description
Level
Routers with Level 1 or Level 2 adjacency configured.
LSPID
LSP identifier. The first six octets form the system ID of the router that originated the LSP.
The next octet is the pseudonode ID. When this byte is , the LSP describes links from the system. When it is nonzero, the LSP is a so-called nonpseudonode LSP. This is similar to a router link-state advertisement (LSA) in the Open Shortest Path First (OSPF) protocol. The LSP describes the state of the originating router.
For each LAN, the designated router for that LAN creates and floods a pseudonode LSP, describing all systems attached to that LAN.
The last octet is the LSP number. If there is more data than can fit in a single LSP, the LSP is divided into multiple LSP fragments. Each fragment has a different LSP number. An asterisk (*) indicates that the LSP was originated by the system on which this command is issued.
Chkpt ID
Unique ID issued to the checkpoint at its creation.
show isis database
To display the Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) database, use the show isis database command in XR EXEC mode.
show isis [ instance instance-id ] database [ level { 1 | 2 } ] [update] [summary] [detail] [verbose] [ * | lsp-id ]
Syntax Description
instance instance-id
(Optional) Displays the IS-IS LSP database for the specified instance only.
level { 1 | 2 }
(Optional) Displays the IS-IS LSP database for Level 1 or Level 2 independently.
update
(Optional) Displays contents of LSP database managed by update thread.
summary
(Optional) Displays the LSP ID number, sequence number, checksum, hold time, and bit information.
detail
(Optional) Displays the contents of each LSP.
verbose
(Optional) Displays the contents of each LSP.
* | lsp-id
(Optional) LSP protocol data units (PDUs) identifier. Displays the contents of a single LSP by its ID number or may contain an * as a wildcard character.
Command Default
No instance ID specified displays the IS-IS LSP database for all the IS-IS instances.
Both Level 1 and Level 2 is configured if no level is specified.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Each of the options for the show isis database command can be entered in an arbitrary string within the same command entry. For example, the following are both valid command specifications and provide the same output: show isis database detail level 2 and show isis database level 2 detail .
The summary keyword used with this command allows you to filter through a large IS-IS database and quickly identify problematic areas.
Task ID
Examples
The following is sample output from the show isis database command with the summary keyword:
RP/0/RP0/CPU0:router# show isis database summary IS-IS 10 Database Summary for all LSPs Active Purged All L1 L2 Total L1 L2 Total L1 L2 Total ----- ----- ----- ----- ----- ----- ----- ----- ----- Fragment 0 Counts Router LSPs: 1 1 2 0 0 0 1 1 2 Pseudo-node LSPs: 0 0 0 0 0 0 0 0 0 All LSPs: 1 1 2 0 0 0 1 1 2 Per Topology IPv4 Unicast ATT bit set LSPs: 0 0 0 0 0 0 0 0 0 OVL bit set LSPs: 0 0 0 0 0 0 0 0 0 All Fragment Counts Router LSPs: 1 1 2 0 0 0 1 1 2 Pseudo-node LSPs: 0 0 0 0 0 0 0 0 0 All LSPs: 1 1 2 0 0 0 1 1 2
This table describes the significant fields shown in the display.
Table 7 show isis database summary Field DescriptionsField
Description
Router LSPs
Active, purged, and total LSPs associated with routers.
Pseudo-node LSPs:
Active, purged, and total LSPs associated with pseudonodes.
All LSPs:
Total active and purged LSPs.
ATT bit set LSPs
Attach bit (ATT). Indicates that the router is also a Level 2 router, and it can reach other areas. Level 1-only routers and Level 1-2 routers that have lost connection to other Level 2 routers use the Attach bit to find the closest Level 2 router. They point to a default route to the closest Level 2 router.
OVL bit set LSPs
Overload bit. Indicates if the IS is congested. If the Overload bit is set, other routers do not use this system as a transit router when calculating routers. Only packets for destinations directly connected to the overloaded router are sent to this router.
show isis database-log
To display the entries in the Intermediate System-to-Intermediate System (IS-IS) database log, use the show isis database-log command in XR EXEC mode.
Syntax Description
level { 1 | 2 }
(Optional) Displays the database log for Level 1 or Level 2 independently.
last number
(Optional) Specifies that the output be restricted to the last number of entries. Range is 1 to 1000.
first number
(Optional) Specifies that the output be restricted to the first number of entries. Range is 1 to 1000.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis database-log command:
RP/0/RP0/CPU0:router# show isis database-log IS-IS 10 Level 1 Link State Database Log New LSP Old LSP WHEN LSPID Op Seq Num Holdtime OL Seq Num Holdtime OL 01:17:19 12b1.03-00 REP 0x00000003 1200 0 0x00000002 340 0 001:06:20 12b1.00-00 REP 0x000001d8 1200 0 0x000001d7 375 0 01:06:00 12b1.03-00 REP 0x00000004 1200 0 0x00000003 520 0 01:05:46 12a1.00-00 REP 0x000001fc 1200 0 0x000001fb 425 0 00:55:01 12b1.00-00 REP 0x000001d9 1200 0 0x000001d8 520 0 00:53:39 12b1.03-00 REP 0x00000005 1200 0 0x00000004 459 0 00:53:19 12a1.00-00 REP 0x000001fd 1200 0 0x000001fc 453 0 00:42:12 12b1.00-00 REP 0x000001da 1200 0 0x000001d9 431 0 00:39:56 12b1.03-00 REP 0x00000006 1200 0 0x00000005 376 0 00:38:54 12a1.00-00 REP 0x000001fe 1200 0 0x000001fd 334 0 00:29:10 12b1.00-00 REP 0x000001db 1200 0 0x000001da 418 0 00:27:22 12b1.03-00 REP 0x00000007 1200 0 0x00000006 446 0 00:25:10 12a1.00-00 REP 0x000001ff 1200 0 0x000001fe 375 0 00:17:04 12b1.00-00 REP 0x000001dc 1200 0 0x000001db 473
This table describes the significant fields shown in the display.
Table 8 show isis database-log Field DescriptionsField
Description
WHEN
Elapsed time (in hh:mm:ss) since the event was logged.
LSPID
LSP identifier. The first six octets form the system ID of the router that originated the LSP.
The next octet is the pseudonode ID. When this byte is , the LSP describes links from the system. When it is nonzero, the LSP is a so-called nonpseudonode LSP. This is similar to a router link-state advertisement (LSA) in the Open Shortest Path First (OSPF) protocol. The LSP describes the state of the originating router.
For each LAN, the designated router for that LAN creates and floods a pseudonode LSP, describing all systems attached to that LAN.
The last octet is the LSP number. If there is more data than can fit in a single LSP, the LSP is divided into multiple LSP fragments. Each fragment has a different LSP number. An asterisk (*) indicates that the LSP was originated by the system on which this command is issued.
New LSP
New router or pseudonode appearing in the topology.
Old LSP
Old router or pseudonode leaving the topology.
Op
Operation on the database: inserted (INS) or replaced (REP).
Seq Num
Sequence number for the LSP that allows other systems to determine if they have received the latest information from the source.
Holdtime
Time the LSP remains valid (in seconds). An LSP hold time of 0 indicates that this LSP was purged and is being removed from the link-state database (LSDB) of all routers. The value indicates how long the purged LSP stays in the LSDB before being completely removed.
OL
Overload bit. Determines if the IS is congested. If the Overload bit is set, other routers do not use this system as a transit router when calculating routers. Only packets for destinations directly connected to the overloaded router are sent to this router.
show isis fast-reroute
Syntax Description
A.B.C.D/length
Network to show per-prefix LFA information.
detail
Use to display tiebreaker information about the backup.
summary Use to display the number of prefixes having protection per priority.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from show isis fast-reroute command that displays per-prefix LFA information:RP/0/RP0/CPU0:router# show isis fast-reroute 10.1.6.0/24 L1 10.1.6.0/24 [20/115] via 10.3.7.47, POS0/3/0/1, router2 FRR backup via 10.1.7.145, GigabitEthernet0/1/0/3, router3The following is sample output from show isis fast-reroute detail command that displays tie-breaker information about the backup:RP/0/RP0/CPU0:router# show isis fast-reroute 10.1.6.0/24 detail L1 10.1.6.0/24 [20/115] low priority via 10.3.7.47, POS0/3/0/1, router2 FRR backup via 10.1.7.145, GigabitEthernet0/1/0/3, router3 P: No, TM: 30, LC: Yes, NP: No, D: No src router2.00-00, 192.168.0.47 L2 adv [20] native, propagatedThe following is sample output from show isis fast-reroute summary command that displays the number of prefixes having protection per priority:RP/0/RP0/CPU0:router#show isis fast-reroute summary IS-IS frr IPv4 Unicast FRR summary Critical High Medium Low Total Priority Priority Priority Priority Prefixes reachable in L1 All paths protected 0 0 2 8 10 Some paths protected 0 0 1 3 4 Unprotected 0 0 1 3 4 Protection coverage 0.00% 0.00% 75.00% 78.57% 77.78% Prefixes reachable in L2 All paths protected 0 0 0 0 0 Some paths protected 0 0 1 0 1 Unprotected 0 0 0 0 0 Protection coverage 0.00% 0.00% 100.00% 0.00% 100.00%show isis hostname
To display the entries in the Intermediate System-to-Intermediate System (IS-IS) router name-to-system ID mapping table, use the show isis hostname command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the IS-IS router name-to-system ID mapping table for the specified IS-IS instance only.
The instance-id argument is the instance identifier (alphanumeric) defined by the router isis command.
Command Default
No instance ID specified displays the IS-IS router name-to-system ID mapping table for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The show isis hostname command does not display entries if the dynamic hostnames are disabled.
Task ID
Examples
The following is sample output from the show isis hostname command with the instance and instance-id values specified:
RP/0/RP0/CPU0:router# show isis instance isp hostname ISIS isp hostnames Level System ID Dynamic Hostname 1 0001.0000.0005 router 2 * 0001.0000.0011 router-11
This table describes the significant fields shown in the display.
Table 9 show isis instance isp hostname Field DescriptionsField
Description
Level
IS-IS level of the router.
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Dynamic Hostname
Hostname of the router.
* Local router.
show isis interface
To display information about the Intermediate System-to-Intermediate System (IS-IS) interfaces, use the show isis interface command in XR EXEC mode.
Syntax Description
type
Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
level { 1 | 2 }
(Optional) Displays IS-IS interface information for Level 1 or Level 2 independently.
brief
(Optional) Displays brief interface output.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis interface command:
RP/0/RP0/CPU0:router#show isis interface GigabitEthernet 0/3/0/2 Gi /3/0/2 Enabled Adjacency Formation: Enabled Prefix Advertisement: Enabled BFD: Disabled BFD Min Interval: 150 BFD Multiplier: 3 Circuit Type: level-2-only Media Type: P2P Circuit Number: 0 Extended Circuit Number: 67111168 Next P2P IIH in: 4 s LSP Rexmit Queue Size: 0 Level-2 Adjacency Count: 1 LSP Pacing Interval: 33 ms PSNP Entry Queue Size: 0 CLNS I/O Protocol State: Up MTU: 4469 IPv4 Unicast Topology: Enabled Adjacency Formation: Running Prefix Advertisement: Running Metric (L1/L2): 10/100 MPLS LDP Sync (L1/L2): Disabled/Disabled IPv6 Unicast Topology: Disabled (Not cfg on the intf) IPv4 Address Family: Enabled Protocol State: Up Forwarding Address(es): 10.3.10.143 Global Prefix(es): 10.3.10.0/24 IPv6 Address Family: Disabled (No topology enabled which uses IPv6) LSP transmit timer expires in 0 ms LSP transmission is idle Can send up to 9 back-to-back LSPs in the next 0 ms
This table describes the significant fields shown in the display.
Table 10 show isis interface Field DescriptionsField
Description
GigabitEthernet0/6/0/0
Status of the interface, either enabled or disabled.
Adjacency formation
Status of adjacency formation, either enabled or disabled.
Prefix Advertisement
Status of advertising connected prefixes, either enabled or disabled.
BFD
Status of Bidirectional Forwarding Detection (BFD), either enabled or disabled.
BFD Min Interval
BFD minimum interval.
BFD Multiplier
BFD multiplier.
Circuit Type
Levels the interface is running on (circuit-type configuration) which may be a subset of levels on the router.
Media Type
Media type on which IS-IS is running.
Circuit Number
Unique ID assigned to a circuit internally (8-bit integer).
Extended Circuit Number
Valid only for point-to-point interfaces (32-bit integer).
LSP Rexmit Queue Size
Number of LSPs pending retransmission on the interface.
Adjacency Count
Number of adjacencies formed with a neighboring router that supports the same set of protocols.
PSNP Entry Queue Size
Number of SNP entries pending inclusion in the next PSNP.
LAN ID
ID of the LAN.
Priority (Local/DIS)
Priority of this interface or priority of the Designated Intermediate System.
Next LAN IIH in
Time (in seconds) in which the next LAN hello message is sent.
LSP Pacing Interval
Interval at which the link-state packet (LSP) transmission rate (and by implication the reception rate of other systems) is to be reduced.
Protocol State
Running state of the protocol (up or down).
MTU
Link maximum transmission unit (MTU).
SNPA
Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
All Level-n ISs
Status of interface membership in Layer 2 multicast group. The status options are Yes or reason for not being a member of the multicast group.
IPv4 Unicast Topology
Status of the topology, either enabled or disabled.
Adjacency Formation
Status of adjacency formation. The status options are Running or a reason for not being ready to form adjacencies.
Prefix Advertisement
Status of advertising prefixes, either enabled or disabled.
Metric (L1/L2)
IS-IS metric for the cost of the adjacency between the originating router and the advertised neighbor, or the metric of the cost to get from the advertising router to the advertised destination (which can be an IP address, an end system (ES), or a connectionless network service (CLNS) prefix).
MPLS LDP Sync (L1/L2)
Status of LDP IS-IS synchronization, either enabled or disabled. When enabled, the state of synchronization (Sync Status) is additionally displayed as either achieved or not achieved.
IPv4 Address Family
Status of the address family, either enabled or disabled.
Protocol State
State of the protocol.
Forwarding Address(es)
Addresses on this interface used by the neighbor for next-hop forwarding.
Global Prefix(es)
Prefixes for this interface included in the LSP.
LSP transmit timer expires in
LSP transmission expiration timer interval (in milliseconds).
LSP transmission is
State of LSP transmission. Valid states are
The following is sample output from the show isis interface command with the brief keyword:
RP/0/0/CPU0:router# show isis interface brief Interface All Adjs Adj Topos Adv Topos CLNS MTU Prio OK L1 L2 Run/Cfg Run/Cfg L1 L2 ----------------- --- --------- --------- --------- ---- ---- -------- PO0/5/0/0 Yes 1 1 1/1 1/1 Up 4469 - - Gi0/6/0/0 Yes 1* 1* 1/1 1/1 Up 1497 64 64
This table describes the significant fields shown in the display.
Table 11 show isis interface brief Field DescriptionsField
Description
Interface
Name of the interface.
All OK
Everything is working as expected for this interface.
Adjs L1 L2
Number of L1 and L2 adjacencies over this interface.
Adj Topos Run/Cfg
Number of topologies that participate in forming adjacencies. Number of topologies that were configured to participate in forming adjacencies.
Adv Topos Run/Cfg
Number of topologies that participate in advertising prefixes. Number of topologies that were configured to participate in advertising prefixes.
CLNS
Status of the Connectionless Network Service. Status options are Up or Down.
MTU
Maximum transfer unit size for the interface.
Prio L1 L2
Interface L1 priority. Interface L2 priority.
show isis lsp-log
To display link-state packet (LSP) log information, use the show isis lsp-log command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the LSP log information for the specified IS-IS instance only.
level { 1 | 2 }
(Optional) Displays the Intermediate System-to-Intermediate System (IS-IS) link-state database for Level 1 or Level 2 independently.
last number
(Optional) Specifies that the output be restricted to the last number of entries. Range is 1 to 20.
first number
(Optional) Specifies that the output be restricted to the first number of entries. Range is 1 to 20.
Command Default
No instance ID specified displays the LSP log information for all the IS-IS instances.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis lsp-log command with the instance and instance-id values specified:
RP/0/RP0/CPU0:router# show isis instance isp lsp-log ISIS isp Level 1 LSP log When Count Interface Triggers 00:02:36 1 00:02:31 1 LSPREGEN 00:02:26 1 PO4/1 DELADJ 00:02:24 1 PO4/1 NEWADJ 00:02:23 1 Gi5/0 DIS 00:01:27 1 Lo0 IPDOWN 00:01:12 1 Lo0 IPUP ISIS isp Level 2 LSP log When Count Interface Triggers 00:02:36 1 00:02:30 1 LSPREGEN 00:02:26 1 PO4/1 DELADJ 00:02:24 1 PO4/1 NEWADJ 00:02:23 1 Gi5/0 DIS 00:02:21 1 AREASET 00:01:27 1 Lo0 IPDOWN 00:01:12 1 Lo0 IPUPshow isis mesh-group
To display Intermediate System-to-Intermediate System (IS-IS) mesh group information, use the show isis mesh-group command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the mesh group information for the specified IS-IS instance only.
Command Default
No instance ID specified displays the IS-IS mesh group information for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis mesh-group command with the instance and instance-id values specified:
RP/0/RP0/CPU0:router# show isis instance isp mesh-group ISIS isp Mesh Groups Mesh group 6: GigabitEthernet 0/4/0/1
This table describes the significant fields shown in the display.
Table 13 show isis instance isp mesh-group Field DescriptionsField
Description
Mesh group
Mesh group number to which this interface is a member. A mesh group optimizes link-state packet (LSP) flooding in nonbroadcast multiaccess (NBMA) networks with highly meshed, point-to-point topologies. LSPs that are first received on interfaces that are part of a mesh group are flooded to all interfaces except those in the same mesh group.
GigabitEthernet0/4/0/1
Interface belonging to mesh group 6.
show isis mpls traffic-eng adjacency-log
To display a log of Multiprotocol Label Switching traffic engineering (MPLS TE) adjacency changes for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis mpls traffic-eng adjacency-log command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the MPLS TE adjacency changes for the specified IS-IS instance only.
last number
(Optional) Specifies that the output is restricted to last number of entries. Range is 1 to 20.
first number
(Optional) Specifies that the output is restricted to first number of entries. Range is 1 to 20.
Command Default
No instance ID specified displays MPLS TE adjacency changes for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the show isis mpls traffic-eng adjacency-log command to display the status of MPLS TE adjacencies.
Task ID
Examples
The following is sample output from the show isis mpls traffic-eng adjacency-log command with the instance and instance-id values specified:
RP/0/RP0/CPU0:router# show isis instance isp mpls traffic-eng adjacency-log IS-IS isp Level-2 MPLS Traffic Engineering adjacency log When Neighbor ID IP Address Interface Status 00:03:36 router-6 172.17.1.6 PO0/3/0/1 Up 00:03:36 router-6 172.17.1.6 PO0/3/0/1 Down 00:02:38 router-6 172.17.1.6 PO0/3/0/1 Up
This table describes the significant fields shown in the display.
Table 14 show isis instance isp mpls traffic-eng adjacency-log Field DescriptionsField
Description
When
Time (in hh:mm:ss) since the entry was recorded in the log.
Neighbor ID
Identification value of the neighbor.
IP Address
Neighbor IP Version 4 (IPv4) address.
Interface
Interface from which a neighbor is learned.
Status
Up (active) or Down (disconnected).
show isis mpls traffic-eng advertisements
To display the latest flooded record from Multiprotocol Label Switching traffic engineering (MPLS TE) for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis mpls traffic-eng advertisements command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the latest flooded record from MPLS TE for the specified IS-IS instance only.
Command Default
No instance ID specified displays the latest flooded record from MPLS TE for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the show isis mpls traffic-eng advertisements command to verify that MPLS TE is flooding its record and that the bandwidths are correct.
Task ID
Examples
The following is sample output from the show isis mpls traffic-eng advertisements command with the instance and instance-id values specified:
RP/0/RP0/CPU0:router# show isis instance isp mpls traffic-eng advertisements ISIS isp Level-2 MPLS Traffic Engineering advertisements System ID: router-9 Router ID: 172.18.0.9 Link Count: 1 Link[0] Neighbor System ID: router-gsr6 (P2P link) Interface IP address: 172.18.0.9 Neighbor IP Address: 172.18.0.6 Admin. Weight: 0 Physical BW: 155520000 bits/sec Reservable BW global: 10000000 bits/sec Reservable BW sub: 0 bits/sec Global pool BW unreserved: [0]: 10000000 bits/sec, [1]: 10000000 bits/sec [2]: 10000000 bits/sec, [3]: 10000000 bits/sec [4]: 10000000 bits/sec, [5]: 10000000 bits/sec [6]: 10000000 bits/sec, [7]: 10000000 bits/sec Sub pool BW unreserved: [0]: 0 bits/sec, [1]: 0 bits/sec [2]: 0 bits/sec, [3]: 0 bits/sec [4]: 0 bits/sec, [5]: 0 bits/sec [6]: 0 bits/sec, [7]: 0 bits/sec Affinity Bits: 0x00000000
This table describes the significant fields shown in the display.
Table 15 show isis instance isp mpls traffic-eng advertisements Field DescriptionsField
Description
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or if the hostname dynamic disable command has been executed, the 6-octet system ID is used.
Router ID
MPLS TE router ID.
Link Count
Number of links that MPLS TE advertised.
Neighbor System ID
System ID of a neighbor number in an area. The six bytes directly preceding the n-selector are the system ID. The system ID length is a fixed size and cannot be changed. The system ID must be unique throughout each area (Level 1) and throughout the backbone (Level 2). In an IS-IS routing domain, each router is represented by a 6-byte hexadecimal system ID. When network administrators maintain and troubleshoot networking devices, they must know the router name and corresponding system ID.
Interface IP address
IP address of the interface.
Neighbor IP Address
IP address of the neighbor.
Admin. Weight
Administrative weight associated with this link.
Physical BW
Link bandwidth capacity (in bits per second).
Reservable BW
Reservable bandwidth on this link.
Global pool BW unreserved
Unreserved bandwidth that is available in the global pool.
Sub pool BW unreserved
Amount of unreserved bandwidth that is available in the subpool.
Affinity Bits
Link attribute flags being flooded. Bits are MPLS-TE specific.
show isis mpls traffic-eng tunnel
To display Multiprotocol Label Switching traffic engineering (MPLS TE) tunnel information for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis mpls traffic-eng tunnel command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the MPLS TE tunnel information for the specified IS-IS instance only.
Command Default
No instance ID specified displays the MPLS TE tunnel information for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the show isis command to find the current status of MPLS TE tunnels.
Tunnels are used in IS-IS next-hop calculations.
Task ID
Examples
The following is sample output from the show isis mpls traffic-eng tunnel command:
RP/0/RP0/CPU0:router# show isis mpls traffic-eng tunnel ISIS isp Level-2 MPLS Traffic Engineering tunnels System Id Tunnel Name Bandwidth Nexthop Metric Mode router-6 tu0 100000 172.18.1.6 0 Relative
This table describes the significant fields shown in the display.
Table 16 show isis mpls traffic-eng tunnel Field DescriptionsField
Description
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Tunnel Name
Name of the MPLS TE tunnel interface.
Bandwidth
MPLS TE-specified tunnel bandwidth of the tunnel.
Nexthop
MPLS TE destination IP address of the tunnel.
Metric
MPLS TE metric of the tunnel.
Mode
MPLS TE metric mode of the tunnel. It can be relative or absolute.
show isis neighbors
To display information about Intermediate System-to-Intermediate System (IS-IS) neighbors, use the show isis neighbors command in XR EXEC mode.
show isis [ instance instance-id ] neighbors [ type interface-path-id | summary ] [detail] [ systemid system-id ]
Syntax Description
Command Default
No instance ID specified displays neighbor information for all the IS-IS instances.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis neighbors command with the instance and instance-id values specified:
Total neighbor count: 3 RP/0//CPU0:router# show isis instance isp neighbors detail IS-IS isp neighbors: System Id Interface SNPA State Holdtime Type IETF-NSF e222e Gi0/1/0/0 *PtoP* Up 23 L1 Capable Area Address(es): 00 IPv4 Address(es): 10.1.0.45* IPv6 Address(es): fe80::212:daff:fe6b:68a8* Topologies: 'IPv4 Unicast' 'IPv6 Unicast' Uptime: 01:09:44 IPFRR: LFA Neighbor: elise LFA IPv4 address: 10.100.1.2 LFA Router address: 192.168.0.45 LFA Interface: Gi0/1/0/0. e333e Gi0/1/0/0.1 0012.da6b.68a8 Up 8 L1 Capable Area Address(es): 00 IPv4 Address(es): 10.100.1.2* Topologies: 'IPv4 Unicast' Uptime: 01:09:46 IPFRR: LFA Neighbor: elise LFA IPv4 address: 10.1.0.45 LFA Router address: 192.168.0.45 LFA Interface: Gi0/1/0/0 m44i Gi0/1/0/1 0012.da62.e0a8 Up 7 L1 Capable Area Address(es): 00 11 IPv4 Address(es): 10.1.2.47* IPv6 Address(es): fe80::212:daff:fe62:e0a8* Topologies: 'IPv4 Unicast' 'IPv6 Unicast' Uptime: 01:09:33 Total neighbor count: 3
This table describes the significant fields shown in the display.
Table 17 show isis instance isp neighbors Field DescriptionsField
Description
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Interface
Interface through which the neighbor is reachable.
SNPA
Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
State
Adjacency state of the neighboring interface. Valid states are: Down, Init, and Up.
Holdtime
Hold time of the neighbor.
Type
Type of adjacency.
IETF-NSF
Specifies whether the neighbor can adhere to the IETF-NSF restart mechanism. Valid states are Capable and Unable.
Area Address(es)
Number of area addresses on this router.
IPv4 Address(es)
IPv4 addresses configured on this router.
Topologies
Address and subaddress families for which IS-IS is configured.
Uptime
Time (in hh:mm:ss) that the neighbor has been up.
IPFRR: LFA Neighbor
IP fast reroute (IPFRR) loop-free alternate (LFA) neighbor.
LFA IPv4 address:
Address of the LFA.
LFA Interface:
LFA interface.
The following is sample output from the show isis neighbors command with the summary keyword specified:
RP/0/RP0/CPU0:router# show isis instance isp neighbors summary ISIS isp neighbor summary: State L1 L2 L1L2 Up 0 0 2 Init 0 0 0 Failed 0 0 0
This table describes the significant fields shown in the display.
Table 18 show isis neighbors summary Field DescriptionsField
Description
State
State of the neighbor is up, initialized, or failed.
L1
Number of Level 1 neighbors.
L2
Number of Level 2 neighbors.
L1L2
Number of Level 1 and 2 neighbors.
show isis protocol
To display summary information about an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis protocol command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the IS-IS adjacencies for the specified IS-IS instance only.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis protocol command:
RP/0/RP0/CPU0:router# show isis protocol IS-IS Router: isp System Id: 0001.0000.0011 IS Levels: level-1-2 Manual area address(es): 49 Routing for area address(es): 49 Non-stop forwarding: Cisco Proprietary NSF Restart enabled Process startup mode: Cold Restart Topologies supported by IS-IS: IPv4 Unicast Level-1 iSPF status: Dormant (awaiting initial convergence) Level-2 iSPF status: Dormant (awaiting initial convergence) No protocols redistributed Distance: 115 Interfaces supported by IS-IS: Loopback0 is running passively (passive in configuration) GigabitEthernet 0/4/0/1 is running actively (active in configuration) GigabitEthernet 0/5/0/1 is running actively (active in configuration)
This table describes the significant fields shown in the display.
Table 19 show isis protocol Field DescriptionsField
Description
System ID:
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
IS Levels:
IS-IS level of the router.
Manual area address(es)
Area addresses that are manually configured.
Routing for areaaddress(es)
Area addresses for which this router provides the routing.
Non-stop forwarding:
Status and name of nonstop forwarding (NSF).
Process startup mode:
Mode in which the last process startup occurred. Valid modes are:
iSPF status:
State of incremental shortest path first (iSPF) configuration for this IS-IS instance. Four states exist:
Disabled if iSPF has not been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm.
Dormant if iSPF has been configured but is awaiting initial convergence before initializing.
Awake if iSPF has been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm.
Active if IS-IS is ready to consider using the iSPF algorithm whenever a new route calculation needs to be run.
No protocols redistributed:
No redistributed protocol information exists to be displayed.
Distance:
Administrative distance for this protocol.
show isis route
To display IP reachability information for an Intermediate System-to-Intermediate System (IS-IS) instance, use the show isis route command in XR EXEC mode.
show isis [ instance instance-id ] [ ipv4 | ipv6 | afi-all ] [ unicast | multicast [ topology { all | topo-name } ] | safi-all ] route [ ip-address mask | ip-address /length [longer-prefixes] ] [summary] [multicast-intact] [backup] [detail]
Syntax Description
instance instance-id
(Optional) Displays the IP reachability information for the specified IS-IS instance only.
ipv4
(Optional) Specifies IP Version 4 address prefixes.
ipv6
(Optional) Specifies IP Version 6 address prefixes.
afi-all
(Optional) Specifies all address prefixes.
unicast
(Optional) Specifies unicast address prefixes.
multicast
(Optional) Specifies multicast address prefixes.
topology
(Optional) Specifies IS-IS paths to intermediate systems.
all
(Optional) Specifies all topologies.
topology topo-name
(Optional) Specifies topology table information and name of the topology table.
safi-all
(Optional) Specifies all secondary address prefixes.
ip-address
(Optional) Network IP address about which routing information should be displayed.
mask
(Optional) Network mask specified in either of two ways:
- Network mask can be a four-part, dotted decimal address. For example, 255.0.0.0 indicates that each bit equal to 1 means the corresponding address bit is a network address.
- Network mask can be indicated as a slash (/) and number. For example, /8 indicates that the first 8 bits of the mask are ones, and the corresponding bits of the address are the network address.
/ length
(Optional) Length of the IP prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value. Range is 0 to 32.
longer-prefixes
(Optional) Displays route and more-specific routes.
summary
(Optional) Displays topology summary information.
multicast-intact
(Optional) Displays multicast intact information for this entry.
systemid
(Optional) Displays multicast information by system ID.
backup
(Optional) Displays backup information for this entry.
detail
(Optional) Displays link-state packet (LSP) details.
Command Default
No instance ID specified displays the IP reachability information for all the IS-IS instances.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis route command:
RP/0//CPU0:router# show isis route IS-IS isp IPv4 Unicast routes Codes: L1 - level 1, L2 - level 2, ia - interarea (leaked into level 1) df - level 1 default (closest attached router), su - summary null C - connected, S - static, R - RIP, B - BGP, O - OSPF i - IS-IS (redistributed from another instance) Maximum parallel path count: 8 L2 10.76.240.6/32 [4/115] via 10.76.245.252, SRP0/1/0/2, isp2 via 10.76.246.252, SRP0/1/0/0, isp2 C 10.76.240.7/32 is directly connected, Loopback0 L2 10.76.240.9/32 [256/115] via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3 L2 10.76.240.10/32 [296/115] via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3 C 10.76.245.0/24 is directly connected, SRP0/1/0/2 C 10.76.246.0/24 is directly connected, SRP0/1/0/0 C 10.76.249.0/26 is directly connected, GigabitEthernet 0/3/0/0 L2 10.101.10.0/24 [296/115] via 10.76.249.2, GigabitEthernet 0/3/0/0, isp3
This table describes the significant fields shown in the display.
Table 20 show isis route ipv4 unicast Field DescriptionsField
Description
C172.18.0.0/24
Connected route for GigabitEthernet interface 0/5/0/0.
C 172.19.1.0/24
Connected route for GigabitEthernet interface 0/4/0/1.
L1 172.35.0.0/24 [10]
Level 1 route to network 172.35.0.0/24.
C 172.18.0/24
Connected route for loopback interface 0.
show isis spf-log
To display how often and why the router has run a full shortest path first (SPF) calculation, use the show isis spf-log command in XR EXEC mode.
show isis [ instance instance-id ] [ [ ipv4 | ipv6 | afi-all ] [ unicast | multicast [ topology { all | topo-name } ] | safi-all ] ] spf-log [ level { 1 | 2 } ] [ ispf | fspf | prc | nhc ] [ detail | verbose | plfrr | ppfrr ] [ last number | first number ]
Syntax Description
instance instance-id
(Optional) Displays the IS-IS SPF log for the specified IS-IS instance only.
ipv4
(Optional) Specifies IP Version 4 address prefixes.
ipv6
(Optional) Specifies IP Version 6 address prefixes.
afi-all
(Optional) Specifies all address prefixes.
unicast
(Optional) Specifies unicast address prefixes.
multicast
(Optional) Specifies multicast address prefixes.
topology all | topo-name
(Optional) Specifies topology table information for all topologies or for the specified topology table ( top-name ).
safi-all
(Optional) Specifies all secondary address prefixes.
level { 1 | 2 }
(Optional) Displays the IS-IS SPF log for Level 1 or Level 2 independently.
ispf
(Optional) Specifies incremental SPF entries only.
fspf
(Optional) Specifies full SPF entries only.
prc
(Optional) Specifies partial route calculations only.
nhc
(Optional) Specifies next-hop route calculations only.
detail
(Optional) Specifies detailed output. Includes a breakdown of the time taken to perform the calculation and changes resulting from the calculation.
verbose
(Optional) Specifies verbose output.
last number
(Optional) Specifies that the output is restricted to the last number of entries. Range is 1 to 210.
first number
(Optional) Specifies that the output is restricted to the first number of entries. Range is 1 to 210.
Command Default
No instance ID specified displays IS-IS adjacencies for all the IS-IS instances.
Both Level 1 and Level 2 are configured if no level is specified.
Displays all types of route calculation (not just fspf, ispf and prc).
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following is sample output from the show isis spf-log command:
RP/0/RP0/CPU0:router# show isis spf-log IS-IS 1 Level 1 IPv4 Unicast Route Calculation Log Time Total Trig Timestamp Type (ms) Nodes Count First Trigger LSP Triggers ----------- ---- ---- ----- ----- ----- ------- --- -------- --- Thurs Aug 19 2004 --- 12:00:50.787 FSPF 1 1 3 ensoft-grs7.00-00 LSPHEADER TLVCODE 12:00:52.846 FSPF 1 1 1 ensoft-grs7.00-00 LSPHEADER 12:00:56.049 FSPF 1 1 1 ensoft-grs7.00-00 TLVCODE 12:01:02.620 FSPF 1 1 2 ensoft-grs7.00-00 NEWADJ LINKTLV IS-IS 1 Level 1 IPv4 Unicast Route Calculation Log Time Total Trig Timestamp Type (ms) Nodes Count First Trigger LSP Triggers ----------- ---- ---- ----- ----- ----- ------- --- -------- --- Mon Aug 19 2004 --- 12:00:50.790 FSPF 0 1 4 ensoft-grs7.00-00 LSPHEADER TLVCODE 12:00:54.043 FSPF 1 1 2 ensoft-grs7.00-00 NEWADJ LSPHEADER 12:00:55.922 FSPF 1 2 1 ensoft-grs7.00-00 NEWLSPO 12:00:56.724 FSPF 1 13 1 ensoft-grs7.00-00 NEWLSPO
This table describes the significant fields shown in the display.
Table 21 show isis spf-log ipv4 unicast Field DescriptionsField
Description
Level
IS-IS level of the router.
Timestamp
Time when the SPF calculation started.
Duration
Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes
Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count
Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP
LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers
List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.
This table lists triggers of a full SPF calculation.
Table 22 List of TriggersTrigger
Description
PERIODIC
Runs a full SPF calculation very 15 minutes.
NEWLEVEL
Configured new level (using is-type) on this router.
RTCLEARED
Cleared IS-IS topology on the router.
MAXPATHCHANGE
Changed IP maximum parallel path.
NEWMETRIC
Changed link metric.
ATTACHFLAG
Changed Level 2 Attach bit.
ADMINDIST
Configured another administrative distance for the IS-IS instance on this router.
NEWADJ
Created a new adjacency to another router.
DELADJ
Deleted adjacency.
BACKUP
Installed backup route.
SEEDISPF
Seed incremental SPF.
NEXTHOP
Changed IP next-hop address.
NEWLSP0
New LSP 0 appeared in the topology.
LSPEXPIRED
Some LSP in the link-state database (LSDB) has expired.
LSPHEADER
Changed important LSP header fields.
TLVCODE
Type, length, and value (TLV) objects code mismatch, indicating that different TLV objects are included in the newest version of an LSP.
LINKTV
Changed Link TLV content.
PREFIXTLV
Changed Prefix TLV content.
AREAADDRTLV
Changed Area address TLV content.
IP ADDRTLV
Changed IP address TLV content.
TUNNEL
Changed RRR tunnel.
The following is sample output from the show isis spf-log command with the first keyword specified:
RP/0//CPU0:router# show isis spf-log first 2 IISIS isp Level 1 IPv4 Unicast Route Calculation Log Time Total Trig Timestamp Type (ms) Nodes Count First Trigger LSP Triggers Mon Aug 16 2004 19:25:35.140 FSPF 1 1 1 12a5.00-00 NEWLSP0 19:25:35.646 FSPF 1 1 1 NEWADJ IISIS isp Level 2 IPv4 Unicast Route Calculation Log Time Total Trig Timestamp Type (ms) Nodes Count First Trigger LSP Triggers Mon Aug 16 2004 19:25:35.139 FSPF 1 1 1 12a5.00-00 NEWLSP0 19:25:35.347 FSPF 1 1 2 12a5.00-00 NEWSADJ TLVCODE
This table describes the significant fields shown in the display.
Table 23 show isis spf-log first Field DescriptionsField
Description
Level
IS-IS level of the router.
Timestamp
Time at which the SPF calculation started.
Type
Type of route calculation. The possible types are incremental SPF (iSPF), full SPF (FSPF), or partial route calculation (PRC).
Time (ms)
Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes
Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count
Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP
LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers
List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.
The following is sample output from the show isis spf-log command with the detail keyword specified:
RP/0//CPU0:router# show isis spf-log detail IISIS isp Level 1 IPv4 Unicast Route Calculation Log Time Total Trig Timestamp Type (ms) Nodes Count First Trigger LSP Triggers Mon Aug 16 2004 19:25:35.140 FSPF 1 1 1 12a5.00-00 NEWLSP0 Delay: 51ms (since first trigger) SPT Calculation CPU Time: 0ms Real Time: 0ms Prefix Updates CPU Time: 1ms Real Time: 1ms New LSP Arrivals: 0 Next Wait Interval: 200ms Results Reach Unreach Total Nodes: 1 0 1 Prefixes (Items) Critical Priority: 0 0 0 High Priority: 0 0 0 Medium Priority 0 0 0 Low Priority 0 0 0 All Priorities 0 0 0 Prefixes (Routes) Critical Priority: 0 - 0 High Priority: 0 - 0 Medium Priority 0 - 0 Low Priority: 0 - 0 All Priorities 0 - 0
This table describes the significant fields shown in the display.
Table 24 show isis spf-log detail Field DescriptionsField
Description
Level
IS-IS level of the router.
Timestamp
Time at which the SPF calculation started.
Type
Type of route calculation. The possible types are incremental SPF (iSPF), full SPF (FSPF), or partial route calculation (PRC).
Time (ms)
Number of milliseconds taken to complete this SPF run. Elapsed time is wall clock time, not CPU time.
Nodes
Number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run.
Trig Count
Number of events that triggered this SPF run. When there is a topology change, often multiple link-state packets (LSPs) are received in a short time. Depending on the configuration of the spf-interval command, a router may wait for a fixed period of time before running a router calculation. This count denotes the number of triggering events that occurred while the router was waiting to run the calculation. For a full description of the triggering events, see List of Triggers.
First Trigger LSP
LSP ID stored by the router whenever a full SPF calculation is triggered by the arrival of a new LSP. The LSP ID can suggest the source of routing instability in an area. If multiple LSPs are causing an SPF run, only the LSP ID of the first received LSP is remembered.
Triggers
List of all reasons that triggered a full SPF calculation. For a list of possible triggers, see List of Triggers.
Delay
Two different delays exist:
- The delay between the time when the route calculation was first triggered and the time when it was run.
- The delay between the end of the last route calculation and the start of this one. This is used to verify that the SPF-interval timers are working correctly, and is only reported for calculations after the first delay.
CPU Time
Two different CPU times exist:
Real Time
Two different real times exist:
New LSP Arrivals
Number of LSP arrivals since the start of this route calculation.
Next Wait Interval
Enforced delay until the next route calculation can be run, based on the spf-interval command configuration.
Reach
Number of reachable nodes or prefixes.
Unreach
Number of unreachable nodes or prefixes.
Total
Total number of nodes or prefixes at various priorities.
show isis statistics
To display Intermediate System-to-Intermediate System (IS-IS) traffic counters, use the show isis statistics command in XR EXEC mode.
Syntax Description
instance instance-id
(Optional) Displays the IS-IS traffic statistics for the specified IS-IS instance only.
type
Interface type. For more information, use the question mark ( ? ) online help function.
interface-path-id
Physical interface or virtual interface.
Note Use the show interfaces command to see a list of all interfaces currently configured on the router.
For more information about the syntax for the router, use the question mark ( ? ) online help function.
Command Default
No instance ID specified displays IS-IS traffic statistics for all the IS-IS instances.
IS-IS traffic statistics are displayed for all interfaces.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The show isis statistics command displays IS-IS traffic counters for the specified interface or all traffic counters if no interface is specified.
Task ID
Examples
The following is sample output from the show isis statistics command that shows all traffic counters:
RP/0/RP0/CPU0:router#show isis statistics IS-IS isp statistics: Fast PSNP cache (hits/tries): 164115/301454 Fast CSNP cache (hits/tries): 41828/43302 Fast CSNP cache updates: 2750 LSP checksum errors received: 0 LSP Dropped: 1441 SNP Dropped: 1958 UPD Max Queue size: 2431 Average transmit times and rate: Hello: 0 s, 987947 ns, 4/s CSNP: 0 s, 1452987 ns, 0/s PSNP: 0 s, 1331690 ns, 0/s LSP: 0 s, 1530018 ns, 1/s Average process times and rate: Hello: 0 s, 874584 ns, 41/s CSNP: 0 s, 917925 ns, 29/s PSNP: 0 s, 1405458 ns, 0/s LSP: 0 s, 4352850 ns, 0/s Level-1: LSPs sourced (new/refresh): 3376/2754 :SPF calculations : 520 ISPF calculations : 0Next Hop Calculations : : 0 IPFRR R-SPF calculations : 0 IPFRR Parallel calculations: 0 IPv6 Unicast SPF calculations : 527 ISPF calculations : 0 Next Hop Calculations : 13 Partial Route Calculations : 1 Level-2: LSPs sourced (new/refresh): 4255/3332 IPv4 Unicast SPF calculations : 432 ISPF calculations : 0 Next Hop Calculations : 8 Partial Route Calculations: 0: IPFRR Parallel calculations: 0 IPv6 Unicast SPF calculations : 444 ISPF calculations : 0 Next Hop Calculations : 82 Partial Route Calculations : 1 Interface GigabitEthernet0/1/0/1.1: Level-1 Hellos (sent/rcvd): 22398/25633 Level-1 DR Elections : 66 Level-1 LSPs (sent/rcvd) : 246/7077 Level-1 CSNPs (sent/rcvd) : 0/33269 Level-1 PSNPs (sent/rcvd) : 22/0 Level-1 LSP Flooding Duplicates : 25129 Level-2 Hellos (sent/rcvd): 22393/67043 Level-2 DR Elections : 55 Level-2 LSPs (sent/rcvd) : 265/437 Level-2 CSNPs (sent/rcvd) : 0/86750 Level-2 PSNPs (sent/rcvd) : 0/0 Level-2 LSP Flooding Duplicates : 78690
This table describes the significant fields shown in the display.
Table 25 show isis statistics Field DescriptionsField
Description
Fast PSNP cache (hits/tries)
Number of successful lookups (hits) along with the number of lookup attempts (tries). To save time or processing power when receiving multiple copies of the same LSP, IS-IS attempts to look up incoming LSPs to see if they have been received recently.
Fast CSNP cache (hits/tries):
Number of successful lookups (hits) along with the number of lookup attempts (tries). To reduce CSNP construction time, IS-IS maintains a cache of CSNPs and attempts to look up CSNP in this cache before transmission on the interface.
Fast CSNP cache updates:
Number of times the CSNP cache has been updated since the last clearing of statistics. The cache is updated on LSP addition or removal from the database.
LSP checksum errors received:
Number of internal checksum errors received in LSPs.
IIH (LSP/SNP) dropped:
Number of hello, LSP, and SNP messages dropped.
IIH (UPD) Max Queue size:
Maximum number of queued packets.
Average transmit times and rate:
Average time taken to transmit the pdu type across all interfaces and the corresponding rate at which the pdu type is being transmitted.
Average process times and rate:
Average time taken to process an incoming pdu type across all interfaces and the corresponding rate at which the pdu type is being received.
LSPs sourced (new/refresh):
Number of LSPs this IS-IS instance has created or refreshed. To find more details on these LSPs, use the show isis lsp-log command.
SPF calculations:
Number of shortest path first (SPF) calculations. SPF calculations are performed only when the topology changes. They are not performed when external routes change. The interval at which SPF calculations are performed is configured using the spf-interval command.
iSPF calculations:
Number of incremental shortest path first (iSPF) calculations. iSPF calculations are performed only when ISPF has been configured in the isis address family configuration submode.
Partial Route Calculations:
Number of partial route calculations (PRCs). PRCs are processor intensive. Therefore, it may be useful to limit their number, especially how often a PRC is done, especially on slower networking devices. Increasing the PRC interval reduces the processor load on the router, but might slow the rate of convergence. The interval at which PRC calculations are performed is configured using the spf-interval command.
Level-(1/2) (LSPs/CSNPs/PSNPs/Hellos) (sent/rcvd):
Number of LSPs, Complete Sequence Number Packets (CSNPs), Partial Sequence Number Packets (PSNPs), and hello packets sent or received on this interface.
PTP Hellos (sent/rcvd):
Point-to-point (PTP) hellos sent and received.
LSP Retransmissions:
Total number of retransmissions on each IS-IS LSP on a point-to-point interface. The LSP retransmission interval can be configured using the retransmit-throttle-interval command.
Level-(1.2) DRElections:
Total number of Designated Intermediate System elections that have taken place. These counts are maintained on an individual level basis.
LSP Flooding Duplicates:
Number of duplicate LSPs filtered from flooding to the neighbor. In case of parallel interfaces to the same neighbor, IS-IS optimizes the flooding by avoiding sending the same LSP copy on other interfaces.
show isis topology
To display a list of connected Intermediate System-to-Intermediate System (IS-IS) routers in all areas, use the show isis topology command in XR EXEC mode.
show isis [ instance instance-id ] [ [ ipv4 | ipv6 | afi-all ] [ unicast | multicast [ topology { all | topo-name } ] | safi-all ] ] | summary | level { 1 | 2 } [multicast-intact] [ systemid system-id ] [detail]
Syntax Description
instance instance-id
(Optional) Displays the IS-IS topology for the specified IS-IS instance only.
ipv4
(Optional) Specifies IP Version 4 address prefixes.
ipv6
(Optional) Specifies IP Version 6 address prefixes.
afi-all
(Optional) Specifies all address prefixes.
unicast
(Optional) Specifies unicast address prefixes.
multicast
(Optional) Specifies multicast address prefixes.
topology topo-name
(Optional) Specifies topology table information and name of the topology table.
safi-all
(Optional) Specifies all secondary address prefixes.
summary
(Optional) Displays a brief list of the IS-IS topology.
level { 1 | 2 }
(Optional) Displays the IS-IS link-state topology for Level 1 or Level 2 independently.
multicast-intact
(Optional) Displays multicast intact information on the IS-IS topology.
systemid system-id
(Optional) Displays the information for the specified router only.
detail
(Optional) Displays detailed information on the IS-IS topology.
Command Default
No instance ID specified displays a list of connected routers in all areas for all the IS-IS instances.
Both Level 1 and Level 2 is configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the show isis topology command to verify the presence and connectivity among all routers in all areas.
Task ID
Examples
The following is sample output from the show isis topology command:
RP/0/RP0/CPU0:router# show isis topology IS-IS isp paths to (Level-1) routers System Id Metric Next-hop Interface SNPA ensoft-5 10 ensoft-5 PO0/4/0/1 *PtoP* ensoft-5 10 ensoft-5 Gi0/5/0/0 0003.6cff.0680 ensoft-11 -- IS-IS isp paths to (Level-2) routers System Id Metric Next-hop Interface SNPA ensoft-5 10 ensoft-5 PO0/4/0/1 *PtoP* ensoft-5 10 ensoft-5 Gi0/5/0/0 0003.6cff.0680 ensoft-11 --
This table describes the significant fields shown in the display.
Table 26 show isis topology ipv4 unicast Field DescriptionsField
Description
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
Metric
Metric assigned to the link and used to calculate the cost from each router using the links in the network to other destinations. Range is 1 to 16777214. Default is 1 to 63 for narrow metric and 1 to 16777214 for wide metric. 0 is set internally if no metric has been specified by the user.
Next-hop
Address of the next-hop.
Interface
Interface used to reach the neighbor.
SNPA
Data-link address (also known as the Subnetwork Point of Attachment [SNPA]) of the neighbor.
The following is sample output from the show isis topology command with the summary keyword specified:
RP/0/RP0/CPU0:router# show isis topology summary IS-IS 10 IS Topology Summary IPv4 Unicast L1 L2 Reach UnReach Total Reach UnReach Total ------- ------- ------- ------- ------- ------- Router nodes: 1 1 2 1 1 2 Pseudo nodes: 0 0 0 0 0 0 Total nodes: 1 1 2 1 1 2
This table describes the significant fields shown in the display.
Table 27 show isis topology summary Field DescriptionsField
Description
L1/L2
IS-IS level of the router.
Reach
Number of router nodes or pseudonodes that are reachable.
UnReach
Number of router nodes or pseudonodes that are unreachable.
Total
Total number of reachable and unreachable nodes.
show protocols (IS-IS)
To group a number of protocol show commands according to the specified address family, use the show protocols command in XR EXEC mode.
Syntax Description
afi-all
(Optional) Specifies all address families.
ipv4
(Optional) Specifies an IPv4 address family.
ipv6
(Optional) Specifies an IPv6 address family.
all
(Optional) Specifies all protocols for a given address family.
protocol
(Optional) Specifies a routing protocol. For the IPv4 address family, the options are:
For the IPv6 address family, the options are:
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
If IPv6 is enabled on an IS-IS instance, the instance is displayed in the show protocols ipv6 command output. IPv4 IS-IS instances are displayed in the show protocols ipv4 command output.
When using the show protocols command with the ipv6 or ipv4 keyword, you get all routing instances in that particular address family—not only IS-IS instances.
Task ID
Examples
The following example shows the output for the show protocols command :
RP/0/RP0/CPU0:router# show protocols ipv4 IS-IS Router: uut System Id: 0000.0000.12a8 IS Levels: level-1-2 Manual area address(es): 49.1515.1515 Routing for area address(es): 49.1515.1515 Non-stop forwarding: Disabled Most recent startup mode: Cold Restart Topologies supported by IS-IS: IPv4 Unicast Level-1 Metric style (generate/accept): Narrow/Narrow ISPF status: Disabled Level-2 Metric style (generate/accept): Narrow/Narrow ISPF status: Disabled Redistributing: static Distance: 115 IPv6 Unicast Level-1 ISPF status: Disabled Level-2 ISPF status: Disabled No protocols redistributed Distance: 45 Interfaces supported by IS-IS: GigabitEthernet 0/6/0/0 is running actively (active in configuration)
This table describes the significant fields shown in the display.
Table 28 show protocols ipv4 Field DescriptionsField
Description
System ID
Dynamic hostname of the system. The hostname is specified using the hostname command. If the dynamic hostname is not known or hostname dynamic disable command has been executed, the 6-octet system ID is used.
IS Levels
IS-IS level of the router.
Manual area address(es)
Area addresses configured manually on the originating router.
Routing for area address(es)
Area addresses for which this router provides the routing.
Non-stop forwarding
Status and name of NSF.
Most recent startup mode
Mode in which the most recent startup was performed.
Topologies supported by IS-IS
Address and subaddress family IS-IS are configured.
Metric style
Type, length, and value (TLV) objects accepted by IS-IS. To configure this value, see the metric-style narrow, metric-style transition, or metric-style wide command.
ISPF status
State of iSPF configuration for this IS-IS instance. Four states exist:
- Disabled if iSPF has not been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm.
- Dormant if iSPF has been configured but is awaiting initial convergence before initializing.
- Awake if iSPF has been configured but is awaiting a full SPF to compile the topology for use by the iSPF algorithm.
- Active if IS-IS is ready to consider using the iSPF algorithm whenever a new route calculation needs to be run.
Redistributing
IS-IS is configured to redistribute IP static routes into Level 1 or Level 2. The redistribute command is used to configure redistribution.
Distance
Administrative distance.
Interfaces supported by IS-IS
Interfaces and their states currently supported by IS-IS. Both operational and configuration status are displayed.
The following example shows how to disable the IPv4 address family, with no output shown for IS-IS IPv4 instances from the show protocols ipv4 command:RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# router isis uut RP/0/RP0/CPU0:router(config-isis)# no address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis)# commit RP/0/RP0/CPU0:router# show protocols ipv4Related Commands
Command
Description
Configures the IS-IS software to generate and accept old-style type, length, and value (TLV) objects.
Configures the IS-IS software to generate and accept both old-style and new-style type length, and value (TLV) objects.
Configures the IS-IS software to generate and accept only new-style type, length, and value (TLV) objects.
Redistributes routes from one IS-IS instance into another instance.
shutdown (IS-IS)
To disable the Intermediate System-to-Intermediate System (IS-IS) protocol on a particular interface, use the shutdown command in interface configuration mode. To re-enable the IS-IS protocol, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
single-topology
To configure the link topology for IP Version 4 (IPv4) when IP Version 6 (IPv6) is configured, use the single-topology command in address family configuration mode. To remove the single-topology command from the configuration file and restore the system to its default condition, use the no form of this command.
Command Default
Performs in multitopology mode in which independent topologies for IPv4 and IPv6 are running in a single area or domain.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the single-topology command to allow Intermediate System-to-Intermediate System (IS-IS) for IPv6 to be configured on interfaces along with an IPv4 network protocol. All interfaces must be configured with the identical set of network protocols, and all routers in the IS-IS area (for Level 1 routing) or the domain (for Level 2 routing) must support the identical set of network layer protocols on all interfaces.
When single-topology support for IPv6 is being used, only old-style type, length, and value (TLV) objects may be used and a single shortest path (SPF) individual level is used to compute IPv4 (if configured) and IPv6 routes. The use of a single SPF means that both IPv4 IS-IS and IPv6 IS-IS routing protocols must share a network topology.
To allow link information to be shared between IPv4 and IPv6, you must configure the single-topology command for an address family. In single-topology IPv6 mode, the configured metric is always the same for both IPv4 and IPv6.
Task ID
Examples
The following example shows how to enable single-topology mode for IPv6:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# net 49.0000.0000.0001.00 RP/0/RP0/CPU0:router(config-isis)# address-family ipv6 unicast RP/0/RP0/CPU0:router(config-isis-af)# single-topologysnmp-server traps isis
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Examples
RP/0/RP0/CPU0:router(config)# snmp-server traps isis adjacency-change isisAdjacencyChange all Enable all IS-IS traps area-mismatch isisAreaMismatch attempt-to-exceed-max-sequence isisAttemptToExceedMaxSequence authentication-failure isisAuthenticationFailure authentication-type-failure isisAuthenticationTypeFailure corrupted-lsp-detected isisCorruptedLSPDetected database-overload isisDatabaseOverload id-len-mismatch isisIDLenMismatch lsp-error-detected isisLSPErrorDetected lsp-too-large-to-propagate isisLSPTooLargeToPropagate manual-address-drops isisManualAddressDrops max-area-addresses-mismatch isisMaxAreaAddressesMismatch orig-lsp-buff-size-mismatch isisOrigLSPBuffSizeMismatch own-lsp-purge isisOwnLSPPurge protocols-supported-mismatch isisProtocolsSupportedMismatch rejected-adjacency isisRejectedAdjacency sequence-number-skip isisSequenceNumberSkip version-skew isisVersionSkew RP/0/RP0/CPU0:router(config)#snmp-server traps isis allRP/0/RP0/CPU0:router(config)# snmp-server traps isis area-mismatch lsp-error-detectedspf-interval
To customize IS-IS throttling of shortest path first (SPF) calculations, use the spf-interval command in address family configuration mode. To restore default values, use the no form of this command.
spf-interval [ initial-wait initial | secondary-wait secondary | maximum-wait maximum ] . .. [ level { 1 | 2 } ]
no spf-interval [ [ initial-wait initial | secondary-wait secondary | maximum-wait maximum ] . .. ] [ level { 1 | 2 } ]
Syntax Description
initial-wait initial
Initial SPF calculation delay (in milliseconds) after a topology change. Range is 0 to 120000.
secondary-wait secondary
Hold time between the first and second SPF calculations (in milliseconds). Range is 0 to 120000.
maximum-wait maximum
Maximum interval (in milliseconds) between two consecutive SPF calculations. Range is 0 to 120000.
level { 1 | 2 }
(Optional) Enables the SPF interval configuration for Level 1 or Level 2 independently.
Command Default
initial-wait initial : 50 milliseconds
secondary-wait secondary : 200 milliseconds
maximum-wait maximum : 5000 milliseconds
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
SPF calculations are performed only when the topology changes. They are not performed when external routes change.
Use the spf-interval command to control how often the software can perform the SPF calculation. The SPF calculation is processor intensive. Therefore, it may be useful to limit how often this calculation is done, especially when the area is large and the topology changes often. Increasing the SPF interval reduces the processor load of the router, but potentially slows the rate of convergence.
Task ID
Examples
The following example shows how to set the initial SPF calculation delay to 10 milliseconds and the maximum interval between two consecutive SPF calculations to 5000 milliseconds:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# spf-interval initial-wait 10 maximum-wait 5000spf prefix-priority (IS-IS)
To assign a priority to an ISIS prefix for customizing the RIB update sequence, use thespf prefix-priority command in address family configuration mode. To restore default values, use the no form of this command.
spf prefix-priority [ level { 1 | 2 } ] { critical | high | medium } { access-list-name | tag tag }
no spf prefix-priority [ level { 1 | 2 } ] { critical | high | medium } [ access-list-name | tag tag ]
Syntax Description
level { 1 | 2 }
(Optional) Enables the assignment of a priority to Level 1 or Level 2 independently.
critical
Assigns a critical priority.
high
Assigns a high priority.
medium
Assigns a medium priority.
access-list-name
Name of an access list.
tag tag
Specifies a tag to indicate priority. The tag argument range is 1 to 4294967295.
Command Default
By default, IPv4 prefixes with a length of 32 and IPv6 prefixes with a length of 128 are given medium priority. The remaining prefixes are given low priority.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the spf prefix-priority command to change the sequence of prefix updates to the RIB after an SPF is run. ISIS installs prefixes in the RIB according to the following priority order:
Critical > High > Medium > Low
The spf prefix-priority command supports prefix lists for the first three priorities. The unmatched prefixes are updated with low priority.
If a spf prefix-priority is specified, the default behavior of prioritizing either length 32 or 128 prefixes for IPv4 or IPv6, respectively, as medium is disabled.
Task ID
Examples
The following example shows how to set the prefix priorities:
RP/0/RP0/CPU0:router(config)# ipv4 prefix-list isis-critical-acl RP/0/RP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 32 ! RP/0/RP0/CPU0:router(config)# ipv4 prefix-list isis-med-acl RP/0/RP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 29 ! RP/0/RP0/CPU0:router(config)# ipv4 prefix-list isis-high-acl RP/0/RP0/CPU0:router(config-ipv4_pfx)# 10 permit 0.0.0.0/0 eq 30 ! RP/0/RP0/CPU0:router(config)# router isis ring RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-af)# spf prefix-priority critical isis-critical-acl RP/0/RP0/CPU0:router(config-isis-af)# spf prefix-priority high isis-high-acl RP/0/RP0/CPU0:router(config-isis-af)# spf prefix-priority medium isis-med-aclsummary-prefix (IS-IS)
To create aggregate addresses for the Intermediate System-to-Intermediate System (IS-IS) protocol, use the summary-prefix command in address family configuration mode. To restore the default behavior, use the no form of this command.
Syntax Description
address
Summary address designated for a range of IPv4 addresses. The address argument must be in four-part, dotted-decimal notation.
/ prefix-length
Length of the IPv4 or IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address compose the prefix (the network portion of the address). A slash must precede the decimal value.
ipv6-prefix
Summary prefix designated for a range of IPv6 prefixes. The ipv6-prefix argument must be in the form documented in RFC 2373, in which the address is specified in hexadecimal using 16-bit values between colons.
level { 1 | 2 }
(Optional) Redistributes routes into Level 1 or Level 2 and summarizes them with the configured address and mask value.
tag tag
Sets a tag value. The value range is 1- 4294967295.
Command Default
All redistributed routes are advertised individually.
Both Level 1 and Level 2 are configured if no level is specified.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Multiple groups of addresses can be summarized for a given level. Routes learned from other routing protocols can also be summarized. The metric used to advertise the summary is the smallest metric of all the more-specific routes. Use the summary-prefix command to help reduce the size of the routing table.
This command also reduces the size of the link-state packets (LSPs) and thus the link-state database. It also helps ensure stability, because a summary advertisement depends on many more specific routes. If one more-specific route flaps, in most cases, this flap does not cause a flap of the summary advertisement.
The drawback of summary addresses is that other routes might have less information to calculate the most optimal routing table for all individual destinations.
Note
When IS-IS advertises a summary prefix, it automatically inserts the summary prefix into the IP routing table but labels it as a “discard” route entry. Any packet that matches the entry is discarded to prevent routing loops. When IS-IS stops advertising the summary prefix, the routing table entry is removed.
Task ID
suppressed
To allow an IS-IS interface to participate in forming adjacencies without advertising connected prefixes in the system link-state packets (LSPs), use the suppressed command in interface configuration mode. To enable advertising connected prefixes, use the no form of this command.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Use the suppressed command to reduce the number of routes that IS-IS has to maintain, improving convergence times after an isolated failure. Improvement is noticeable if the command is used widely throughout the network. Other routers in the domain do not install routes to the affected connected prefixes.
Task ID
tag (IS-IS)
To associate and advertise a tag with the prefix of an IS-IS interface, use the tag command in interface address family configuration mode. To restore the default behavior, use the no form of this command.
Syntax Description
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to associate and advertise an interface tag:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# interface GigabitEthernet 0/3/0/0 RP/0/RP0/CPU0:router(config-isis-if)# address-family ipv4 unicast RP/0/RP0/CPU0:router(config-isis-if-af)# tag 234topology-id
To differentiate one topology in the domain from another while configuring a multicast routing table, use the topology-id command in Intermediate System-to-Intermediate System (IS-IS) address family configuration submode. To disable the topology use the no form of the command.
Syntax Description
isis-multicast-topology-id-number
ID number for a specific IS-IS multicast topology. Range is 6 to 4095.
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
Examples
The following example shows how to differentiate a topology from another in the multicast routing table in IS-IS routing:
RP/0/RP0/CPU0:router(config)# router isis isp RP/0/RP0/CPU0:router(config-isis)# address-family ipv4 multicast topology green RP/0/RP0/CPU0:router(config-isis-af)# topology-id 2666trace (IS-IS)
To set the the IS-IS buffer size, use the trace command in router configuration mode. To return to the default value, use the no form of this command.
Syntax Description
detailed Specifies the buffer size for detailed traces. Range is
severe Specifies the buffer size for severe traces. Range is
standard Specifies the buffer size for standard traces. Range is
max-trace-entries Sets the maximum number of trace entries. Range is 1-20000
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
Task ID
