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Contents
BGP Commands_ M through N
- match as-path
- match community
- neighbor activate
- neighbor advertise-map
- neighbor advertisement-interval
- neighbor capability orf prefix-list
- neighbor default-originate
- neighbor description
- neighbor ebgp-multihop
- neighbor ha-mode graceful-restart
- neighbor inherit peer-session
- neighbor maximum-prefix (BGP)
- neighbor peer-group (assigning members)
- neighbor peer-group (creating)
- neighbor prefix-list
- neighbor remote-as
- neighbor route-map
- neighbor shutdown
- neighbor soft-reconfiguration
- neighbor unsuppress-map
- neighbor update-source
- network (BGP and multiprotocol BGP)
- network backdoor
match as-path
To match a BGP autonomous system path that is specified by an access list, use the match as-path command in route-map configuration mode. To remove a path list entry, use the no form of this command.
Command History
Release
Modification
10.0
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Use the ip as-path access-list command to create an access list that determines which AS path is specified. Then use the match as-path command to create a route map based on matching the access list that determined the AS path.
The values set by the combination of the match as-path and set weight commands override global values. For example, the weights assigned with the match as-path and set weight route-map configuration commands override the weight assigned using the neighbor weight command.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.
Examples
The following example configures a route map that matches on the autonomous system path specified by access list 20:
route-map IGP2BGP match as-path 20Related Commands
Command
Description
ip as-path access-list
Configures an AS path filter using a regular expression.
match community
Matches a BGP community.
match interface (IP)
Distributes routes that have their next hop out one of the interfaces specified.
match ip address
Distributes any routes that have a destination network number address that is permitted by a standard or extended access list, and performs policy routing on packets.
match ip next-hop
Redistributes any routes that have a next hop router address passed by one of the access lists specified.
match ip route-source
Redistributes routes that have been advertised by routers and access servers at the address specified by the access lists.
match metric (IP)
Redistributes routes with the metric specified.
match route-type (IP)
Redistributes routes of the specified type.
match tag
Redistributes routes in the routing table that match the specified tags.
neighbor weight
Assigns weight to a neighbor connection.
route-map (IP)
Defines the conditions for redistributing routes from one routing protocol into another, or enables policy routing.
set as-path
Modifies an autonomous system path for BGP routes.
set automatic-tag
Automatically computes the tag value in a route map configuration.
set community
Sets the BGP communities attribute.
set level (IP)
Indicates where to import routes.
set local-preference
Specifies a preference value for the autonomous system path.
set metric (BGP, OSPF, RIP)
Sets the metric value for a routing protocol.
set metric-type
Sets the metric type for the destination routing protocol.
set next-hop
Specifies the address of the next hop.
set origin (BGP)
Sets the BGP origin code.
set tag (IP)
Sets the value of the destination routing protocol.
set weight
Specifies the BGP weight for the routing table.
match community
To match a Border Gateway Protocol (BGP) community, use the match community command in route-map configuration mode. To remove the match community command from the configuration file and restore the system to its default condition where the software removes the BGP community list entry, use the no form of this command.
match community { standard-list-number | expanded-list-number | community-list-name [exact] }
no match community { standard-list-number | expanded-list-number | community-list-name [exact] }
Syntax Description
standard-list-number
Specifies a standard community list number from 1 to 99 that identifies one or more permit or deny groups of communities.
expanded-list-number
Specifies an expanded community list number from 100 to 500 that identifies one or more permit or deny groups of communities.
community-list-name
The community list name.
exact
(Optional) Indicates that an exact match is required. All of the communities and only those communities specified must be present.
Command History
Release
Modification
12.1
This command was introduced.
12.1(9)E
Named community list support was integrated into Cisco IOS Release 12.1(9)E.
12.2(8)T
Named community list support was integrated into Cisco IOS Release 12.2(8)T.
12.0(22)S
The maximum number of expanded extended community list numbers was changed from 199 to 500 in Cisco IOS Release 12.0(22)S.
12.2(14)S
The maximum number of expanded community lists was changed from 199 to 500 and named community list support were integrated into Cisco IOS Release 12.2(14)S.
12.2(15)T
The maximum number of expanded extended community list numbers was changed from 199 to 500 in Cisco IOS Release 12.2(15)T.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
A route map can have several parts. Any route that does not match at least one match command relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.
Matching based on community list number is one of the types of match commands applicable to BGP.
Examples
The following example shows that the routes matching community list 1 will have the weight set to 100. Any route that has community 109 will have the weight set to 100.
Router(config)# ip community-list 1 permit 109 Router(config)# route-map set_weight Router(config-route-map)# match community 1 Router(config-route-map)# set weight 100The following example shows that the routes matching community list 1 will have the weight set to 200. Any route that has community 109 alone will have the weight set to 200.
Router(config)# ip community-list 1 permit 109 Router(config)# route-map set_weight Router(config-route-map)# match community 1 exact Router(config-route-map)# set weight 200In the following example, the routes that match community list LIST_NAME will have the weight set to 100. Any route that has community 101 alone will have the weight set to 100.
Router(config)# ip community-list LIST_NAME permit 101 Router(config)# route-map set_weight Router(config-route-map)# match community LIST_NAME Router(config-route-map)# set weight 100The following example shows that the routes that match expanded community list 500. Any route that has extended community 1 will have the weight set to 150.
Router(config)# ip community-list 500 permit [0-9]* Router(config)# route-map MAP_NAME permit 10 Router(config-route-map)# match extcommunity 500 Router(config-route-map)# set weight 150neighbor activate
To enable the exchange of information with a Border Gateway Protocol (BGP) neighbor, use the neighbor activate command in address family configuration mode or router configuration mode. To disable the exchange of an address with a BGP neighbor, use the no form of this command.
neighbor { ip-address | peer-group-name | ipv6-address% } activate
no neighbor { ip-address | peer-group-name | ipv6-address% } activate
Syntax Description
ip-address
IP address of the neighboring router.
peer-group-name
Name of the BGP peer group.
ipv6-address
IPv6 address of the BGP neighbor.
%
(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.
Command Default
The exchange of addresses with BGP neighbors is enabled for the IPv4 address family. Enabling address exchange for all other address families is disabled.
NoteAddress exchange for address family IPv4 is enabled by default for each BGP routing session configured with the neighbor remote-as command unless you configure the no bgp default ipv4-activate command before configuring the neighbor remote-as command, or you disable address exchange for address family IPv4 with a specific neighbor by using the no neighbor activate command.
Command History
Release
Modification
11.0
This command was introduced.
12.0(5)T
Support for address family configuration mode and the IPv4 address family was added.
12.2(2)T
The ipv6-address argument and support for the IPv6 address family were added.
12.0(21)ST
This command was integrated into Cisco IOS Release 12.0(21)ST.
12.0(22)S
This command was integrated into Cisco IOS Release 12.0(22)S.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
The % keyword was added
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
Cisco IOS XE Release 2.1
This command was introduced on Cisco ASR 1000 Series Routers.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.
Usage Guidelines
Use this command to advertise address information in the form of an IP or IPv6 prefix. The address prefix information is known as Network Layer Reachability Information (NLRI) in BGP.
The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces. This keyword does not need to be used for non-link-local IPv6 addresses.
NoteThe use of the no form of the neighbor activate command will remove all configurations associated with the neighbor both inside and outside address family configuration mode. This command is not the same as the neighbor shutdown command, and you should not use this command to disconnect a BGP adjacency.
Examples
The following example shows how to enable address exchange for address family vpnv4 for all neighbors in the BGP peer group named PEPEER and for the neighbor 10.0.0.44:
Router(config)# address-family vpnv4 Router(config-router-af)# neighbor PEPEER activate Router(config-router-af)# neighbor 10.0.0.44 activate Router(config-router-af)# exit-address-familyExamples
The following example shows how to enable address exchange for address family IPv4 unicast for all neighbors in the BGP peer group named group1 and for the BGP neighbor 172.16.1.1:
Device(config)# address-family ipv4 unicast Device(config-router-af)# neighbor group1 activate Device(config-router-af)# neighbor 172.16.1.1 activateExamples
The following example shows how to enable address exchange for address family IPv6 for all neighbors in the BGP peer group named group2 and for the BGP neighbor 7000::2:
Device(config)# address-family ipv6 Device(config-router-af)# neighbor group2 activate Device(config-router-af)# neighbor 7000::2 activateThe following example shows that the no command will remove all configurations associated with a neighbor both inside and outside the address family configuration mode. The first set of commands shows the configuration for a specific neighbor.
Device(config)# router bgp 64496 Device(config-router)# bgp log neighbor changes Device(config-router)# neighbor 10.0.0.1 remote-as 64497 Device(config-router)# neighbor 10.0.0.1 update-source Loopback0 Device(config-router)# address-family ipv4 Device(config-router-af)# no synchronization Device(config-router-af)# no neighbor 10.0.0.1 activate Device(config-router-af)# no auto-summary Device(config-router-af)# exit-address-family Device(config-router)address-family vpnv4 Device(config-router-af)# neighbor 10.0.0.1 activate Device(config-router-af)# neighbor 10.0.0.1 send-community extended Device(config-router-af)# exit-address-family Device(config-router)# address-family ipv4 vrf vrf1 Device(config-router-af)# no synchronization Device(config-router-af)# redistribute connected Device(config-router-af)# neighbor 192.168.1.4 remote-as 100 Device(config-router-af)# neighbor 192.168.1.4 version 4 Device(config-router-af)# neighbor 192.168.1.4 activate Device(config-router-af)# neighbor 192.168.1.4 weight 200 Device(config-router-af)# neighbor 192.168.1.4 prefix-list test out Device(config-router-af)# exit-address-familyThe following example shows the router configuration after the use of the no command.
Device(config)# router bgp 64496 Device(config-router)# address-family ipv4 vrf vrf1 Device(config-router-af)# no neighbor 192.168.1.4 activate 01:01:19: %BGP_SESSION-5-ADJCHANGE: neighbor 192.168.1.4 IPv4 Unicast vpn vrf vrf1 topology base removed from session Neighbor deleted 01:01:19: %BGP-5-ADJCHANGE: neighbor 192.168.1.4 vpn vrf vrf1 Down Neighbor deleted Device(config-router-af)# do show running-config | begin router bgp router bgp 64496 bgp log-neighbor-changes neighbor 10.0.0.1 remote-as 64496 neighbor 10.0.0.1 update-source Loopback0 ! address-family ipv4 no synchronization no neighbor 10.0.0.1 activate no auto-summary exit-address-family ! address-family vpnv4 neighbor 10.0.0.1 activate neighbor 10.0.0.1 send-community extended exit-address-family ! address-family ipv4 vrf vrf1 no synchronization redistribute connected exit-address-familyThis example shows the router configuration when the neighbor is reactivated.
Device(config)# router bgp 64496 Device(config-router)# address-family ipv4 vrf vrf1 Device(config-router-af)# neighbor 192.168.1.4 activate 01:02:26: %BGP-5-ADJCHANGE: neighbor 192.168.1.4 vpn vrf vrf1 Up Device(config-router-af)# do show running-config | begin router bgp router bgp 64496 bgp log-neighbor-changes neighbor 10.0.0.1 remote-as 64496 neighbor 10.0.0.1 update-source Loopback0 ! address-family ipv4 no synchronization no neighbor 10.0.0.1 activate no auto-summary exit-address-family ! address-family vpnv4 neighbor 10.0.0.1 activate neighbor 10.0.0.1 send-community extended exit-address-family ! address-family ipv4 vrf vrf1 no synchronization redistribute connected neighbor 192.168.1.4 remote-as 100 neighbor 192.168.1.4 version 4 neighbor 192.168.1.4 activate exit-address-familyRelated Commands
Command
Description
address-family ipv4
Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv4 address prefixes.
address-family ipv6
Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv6 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv4 address prefixes.
address-family vpnv6
Places the router in address family configuration mode for configuring routing sessions, such as BGP, that use standard VPNv6 address prefixes.
exit-address-family
Exits from the address family submode.
neighbor remote-as
Adds an entry to the BGP or multiprotocol BGP neighbor table.
neighbor advertise-map
To advertise the routes in the BGP table matching the configured route-map, use the neighbor advertise-map command in router configuration mode. To disable route advertisement, use the no form of this command.
neighbor { ip-address | ipv6-address } advertise-map map-name { exist-map map-name | non-exist-map map-name }
no neighbor { ip-address | ipv6-address } advertise-map map-name { exist-map map-name | non-exist-map map-name }
Syntax Description
ip-address
Specifies the IPv4 address of the router that should receive conditional advertisements.
ipv6-address
Specifies the IPv6 address of the router that should receive conditional advertisements.
advertise-map map-name
Specifies the name of the route map that will be advertised if the conditions of the exist map or non-exist map are met.
exist-map map-name
Specifies the name of the exist-map that is compared with the routes in the BGP table to determine whether the advertise-map route is advertised or not.
non-exist-map map-name
Specifies the name of the non-exist-map that is compared with the routes in the BGP table to determine whether the advertise-map route is advertised or not.
Command History
Release
Modification
11.1CC
This command was introduced.
11.2
This command was integrated into Cisco IOS Release 11.2.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
15.3(2)S
This command was integrated into Cisco IOS Release 15.3(2)S.
Cisco IOS XE Release 3.9S
This command was integrated into Cisco IOS XE Release 3.9S.
Usage Guidelines
Use the neighbor advertise-map command to conditionally advertise selected routes. The routes (prefixes) that will be conditionally advertised are defined in two route maps: an advertise map and either an exist map or non-exist map.
- The route map associated with the exist map or non-exist map specifies the prefix that the BGP speaker will track.
- The route map associated with the advertise map specifies the prefix that will be advertised to the specified neighbor when the condition is met.
If an exist map is configured, the condition is met when the prefix exists in both the advertise map and the exist map.
If a non-exist map is configured, the condition is met when the prefix exists in the advertise map, but does not exist in the non-exist map.
If the condition is not met, the route is withdrawn and conditional advertisement does not occur. All routes that may be dynamically advertised or not advertised need to exist in the BGP routing table for conditional advertisement to occur.
Examples
The following router configuration example configures BGP to conditionally advertise a prefix to the 10.2.1.1 neighbor using an exist map. If the prefix exists in MAP1 and MAP2, the condition is met and the prefix is advertised.
router bgp 5 address-family ipv4 unicast neighbor 10.2.1.1 advertise-map MAP1 exist-map MAP2The following address family configuration example configures BGP to conditionally advertise a prefix to the 10.1.1.1 neighbor using a non-exist map. If the prefix exists in MAP3 but not MAP4, the condition is met and the prefix is advertised.
router bgp 5 address-family ipv4 unicast neighbor 10.1.1.1 advertise-map MAP3 non-exist-map MAP4Related Commands
Command
Description
address-family ipv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
address-family ipv6
Places router in address family configuration mode for configuring routing sessions, such as BGP, that use standard IPv6 address prefixes
route-map
Defines the conditions for redistributing routes from one routing protocol into another, or enables policy routing.
neighbor advertisement-interval
To set the minimum route advertisement interval (MRAI) between the sending of BGP routing updates, use the neighbor advertisement-interval command in address family or router configuration mode. To restore the default value, use the no form of this command.
neighbor { ip-address | peer-group-name } advertisement-interval seconds
no neighbor { ip-address | peer-group-name } advertisement-interval seconds
Command Default
eBGP sessions not in a VRF: 30 seconds
eBGP sessions in a VRF: 0 seconds
iBGP sessions: 0 seconds
Command History
Release
Modification
10.3
This command was introduced.
12.0(7)T
Address family configuration mode was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
12.4T, 12.2SB, 12.2SE, 12.2SG, 12.2SR, 12.2SX, Cisco IOS XE 2.1
This command was modified. The default value for eBGP sessions in a VRF and for iBGP sessions changed from .5 seconds to 0 seconds.
Usage Guidelines
When the MRAI is equal to 0 seconds, BGP routing updates are sent as soon as the BGP routing table changes.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.
Examples
The following router configuration mode example sets the minimum time between sending BGP routing updates to 10 seconds:
router bgp 5 neighbor 10.4.4.4 advertisement-interval 10The following address family configuration mode example sets the minimum time between sending BGP routing updates to 10 seconds:
router bgp 5 address-family ipv4 unicast neighbor 10.4.4.4 advertisement-interval 10Related Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
neighbor peer-group (creating)
Creates a BGP peer group.
neighbor capability orf prefix-list
To advertise outbound route filter (ORF) capabilities to a peer router, use the neighbor capability orf prefix-list command in address family or router configuration mode. To disable ORF capabilities, use the no form of this command.
neighbor ip-address capability orf prefix-list [ receive | send | both ]
no neighbor ip-address capability orf prefix-list [ receive | send | both ]
Command History
Release
Modification
12.0(11)ST
This command was introduced.
12.2(4)T
This command was integrated into Cisco IOS Release 12.2(4)T.
12.0(22)S
This command was integrated into Cisco IOS Release 12.0(22)S.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
The neighbor capability orf prefix-list command is used to reduce the number of BGP prefixes that a BGP speaker sends or receives from a peer router based on prefix filtering.
In most configurations, this command will be used to advertise both send and receive ORF capabilities with the both keyword. However, this feature can be configured in one direction between two routers with one router configured to send ORF capabilities and another router configured to receive ORF capabilities from the first router.
Examples
The following examples configure routers to advertise ORF send or receive capabilities to BGP neighbors.
Examples
The following example creates an outbound route filter and configures Router-A (10.1.1.1) to advertise the filter to Router-B (172.16.1.2). An IP prefix list named FILTER is created to specify the 192.168.1.0/24 subnet for outbound route filtering. The ORF send capability is configured on Router-A so that Router-A can advertise the outbound route filter to Router-B.
ip prefix-list FILTER seq 10 permit 192.168.1.0/24 ! router bgp 100 address-family ipv4 unicast neighbor 172.16.1.2 remote-as 200 neighbor 172.16.1.2 ebgp-multihop neighbor 172.16.1.2 capability orf prefix-list send neighbor 172.16.1.2 prefix-list FILTER in exitExamples
The following example configures Router-B to advertise the ORF receive capability to Router-A. Router-B will install the outbound route filter, defined in the FILTER prefix list, after ORF capabilities have been exchanged. An inbound soft reset is initiated on Router-B at the end of this configuration to activate the outbound route filter.
router bgp 200 address-family ipv4 unicast neighbor 10.1.1.1 remote-as 100 neighbor 10.1.1.1 ebgp-multihop 255 neighbor 10.1.1.1 capability orf prefix-list receive end clear ip bgp 10.1.1.1 in prefix-filter
NoteThe inbound soft refresh must be initiated with the clear ip bgp command in order for the BGP ORF feature to function.
neighbor default-originate
To allow a BGP speaker (the local router) to send the default route 0.0.0.0 to a neighbor for use as a default route, use the neighbor default-originate command in address family or router configuration mode. To send no route as a default, use the no form of this command.
neighbor { ip-address | peer-group-name } default-originate [ route-map map-name ]
no neighbor { ip-address | peer-group-name } default-originate [ route-map map-name ]
Command History
Release
Modification
11.0
This command was introduced.
12.0
Modifications were added to permit extended access lists.
12.0(7)T
Address family configuration mode was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command does not require the presence of 0.0.0.0 in the local router. When used with a route map, the default route 0.0.0.0 is injected if the route map contains a match ip address clause and there is a route that matches the IP access list exactly. The route map can contain other match clauses also.
You can use standard or extended access lists with the neighbor default-originate command.
Examples
In the following router configuration example, the local router injects route 0.0.0.0 to the neighbor 172.16.2.3 unconditionally:
router bgp 109 network 172.16.0.0 neighbor 172.16.2.3 remote-as 200 neighbor 172.16.2.3 default-originateIn the following example, the local router injects route 0.0.0.0 to the neighbor 172.16.2.3 only if there is a route to 192.168.68.0 (that is, if a route with any mask exists, such as 255.255.255.0 or 255.255.0.0):
router bgp 109 network 172.16.0.0 neighbor 172.16.2.3 remote-as 200 neighbor 172.16.2.3 default-originate route-map default-map ! route-map default-map 10 permit match ip address 1 ! access-list 1 permit 192.168.68.0In the following example, the last line of the configuration has been changed to show the use of an extended access list. The local router injects route 0.0.0.0 to the neighbor 172.16.2.3 only if there is a route to 192.168.68.0 with a mask of 255.255.0.0:
router bgp 109 network 172.16.0.0 neighbor 172.16.2.3 remote-as 200 neighbor 172.16.2.3 default-originate route-map default-map ! route-map default-map 10 permit match ip address 100 ! access-list 100 permit ip host 192.168.68.0 host 255.255.0.0Related Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
neighbor ebgp-multihop
Accepts and attempts BGP connections to external peers residing on networks that are not directly connected.
neighbor description
To associate a description with a neighbor, use the neighbor description command in router configuration mode or address family configuration mode. To remove the description, use the no form of this command.
neighbor { ip-address | peer-group-name } description text
no neighbor { ip-address | peer-group-name } description [text]
Syntax Description
ip-address
IP address of the neighbor.
peer-group-name
Name of an EIGRP peer group. This argument is not available in address-family configuration mode.
text
Text (up to 80 characters in length) that describes the neighbor.
Command History
Release
Modification
11.3
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
15.0(1)M
This command was modified. Address-family configuration mode was added.
12.2(33)SRE
This command was integrated into Cisco IOS Release 12.2(33)SRE.
Cisco IOS XE Release 2.6
This command was integrated into Cisco IOS XE Release 2.6.
Examples
In the following examples, the description of the neighbor is “peer with example.com”:
Router(config)# router bgp 109 Router(config-router)# network 172.16.0.0 Router(config-router)# neighbor 172.16.2.3 description peer with example.comIn the following example, the description of the address family neighbor is “address-family-peer”:
Router(config)# router eigrp virtual-name Router(config-router)# address-family ipv4 autonomous-system 4453 Router(config-router-af)# network 172.16.0.0 Router(config-router-af)# neighbor 172.16.2.3 description address-family-peerneighbor ebgp-multihop
To accept and attempt BGP connections to external peers residing on networks that are not directly connected, use the neighbor ebgp-multihop command in router configuration mode. To return to the default, use the no form of this command.
neighbor { ip-address | ipv6-address | peer-group-name } ebgp-multihop [ttl]
no neighbor { ip-address | ipv6-address | peer-group-name } ebgp-multihop
Command History
Release
Modification
10.0
This command was introduced.
11.0
The peer-group-name argument was added.
12.2(33)SRA
The ipv6-address argument and support for the IPv6 address family were added.
12.2(33)SB
This command was integrated into Cisco IOS Release 12.2(33)SB.
12.2(33)SXI
This command was integrated into Cisco IOS Release 12.2(33)SXI.
Cisco IOS XE Release 3.1S
This command was integrated into Cisco IOS XE Release 3.1S.
Usage Guidelines
This feature should be used only under the guidance of Cisco technical support staff.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.
To prevent the creation of loops through oscillating routes, the multihop will not be established if the only route to the multihop peer is the default route (0.0.0.0).
Examples
The following example allows connections to or from neighbor 10.108.1.1, which resides on a network that is not directly connected:
router bgp 109 neighbor 10.108.1.1 ebgp-multihopRelated Commands
Command
Description
neighbor advertise-map non-exist-map
Allows a BGP speaker (the local router) to send the default route 0.0.0.0 to a neighbor for use as a default route.
neighbor peer-group (creating)
Creates a BGP peer group.
network (BGP and multiprotocol BGP)
Specifies the list of networks for the BGP routing process.
neighbor ha-mode graceful-restart
To enable or disable the Border Gateway Protocol (BGP) graceful restart capability for a BGP neighbor or peer group, use the neighbor ha-mode graceful-restart command in router configuration mode. To remove from the configuration the BGP graceful restart capability for a neighbor, use the no form of this command.
neighbor { ip-address | peer-group-name } ha-mode graceful-restart [disable]
no neighbor { ip-address | peer-group-name } ha-mode graceful-restart [disable]
Usage Guidelines
The neighbor ha-mode graceful-restart command is used to enable or disable the graceful restart capability for an individual BGP neighbor or peer group in a BGP network. Use the disable keyword to disable the graceful restart capability when graceful restart has been previously enabled for the BGP peer.
The graceful restart capability is negotiated between nonstop forwarding (NSF)-capable and NSF-aware peers in OPEN messages during session establishment. If the graceful restart capability is enabled after a BGP session has been established, the session will need to be restarted with a soft or hard reset.
The graceful restart capability is supported by NSF-capable and NSF-aware routers. A router that is NSF-capable can perform a stateful switchover (SSO) operation (graceful restart) and can assist restarting peers by holding routing table information during the SSO operation. A router that is NSF-aware functions like a router that is NSF-capable but cannot perform an SSO operation.
To enable the BGP graceful restart capability globally for all BGP neighbors, use the bgp graceful-restartcommand. When the BGP graceful restart capability is configured for an individual neighbor, each method of configuring graceful restart has the same priority, and the last configuration instance is applied to the neighbor.
Use the show ip bgp neighbors command to verify the BGP graceful restart configuration for BGP neighbors.
Examples
The following example enables the BGP graceful restart capability for the BGP neighbor, 172.21.1.2:
router bgp 45000 bgp log-neighbor-changes address-family ipv4 unicast neighbor 172.21.1.2 remote-as 45000 neighbor 172.21.1.2 activate neighbor 172.21.1.2 ha-mode graceful-restart endThe following example enables the BGP graceful restart capability globally for all BGP neighbors and then disables the BGP graceful restart capability for the BGP peer group PG1. The BGP neighbor 172.16.1.2 is configured as a member of the peer group PG1 and inherits the disabling of the BGP graceful restart capability.
router bgp 45000 bgp log-neighbor-changes bgp graceful-restart address-family ipv4 unicast neighbor PG1 peer-group neighbor PG1 remote-as 45000 neighbor PG1 ha-mode graceful-restart disable neighbor 172.16.1.2 peer-group PG1 endRelated Commands
Command
Description
bgp graceful-restart
Enables the BGP graceful restart capability globally for all BGP neighbors.
ha-mode graceful-restart
Enables or disables the BGP graceful restart capability for a BGP peer session template.
show ip bgp neighbors
Displays information about the TCP and BGP connections to neighbors.
neighbor inherit peer-session
To send a peer session template to a neighbor so that the neighbor can inherit the configuration, use the neighbor inherit peer-sessioncommand in address family or router configuration mode. To stop sending the peer session template, use the no form of this command.
neighbor ip-address inherit peer-session session-template-name
no neighbor ip-address inherit peer-session session-template-name
Command History
Release
Modification
12.0(24)S
This command was introduced.
12.2(18)S
This command was integrated into Cisco IOS Release 12.2(18)S.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
This command is used to send locally configured session templates to the specified neighbor. If the session template is configured to inherit configurations from other session templates, the specified neighbor will also indirectly inherit these configurations from the other session templates. A neighbor can directly inherit only one peer session template and indirectly inherit up to seven peer session templates.
NoteA Border Gateway Protocol (BGP) neighbor cannot be configured to work with both peer groups and peer templates. A BGP neighbor can be configured to belong only to a peer group or to inherit policies only from peer templates.
Examples
The following example configures the 172.16.0.1 neighbor to inherit the CORE1 peer session template. The 172.16.0.1 neighbor will also indirectly inherit the configuration from the peer session template named INTERNAL-BGP. The explicit remote-as statement is required for the neighbor inherit statement to work. If a peering is not configured, the specified neighbor will not accept the session template.
Router(config)# router bgp 101 Router(config)# neighbor 172.16.0.1 remote-as 202 Router(config-router)# neighbor 172.16.0.1 inherit peer-session CORE1Related Commands
Command
Description
exit peer-session
Exits session-template configuration mode and enters router configuration mode.
inherit peer-session
Configures a peer session template to inherit the configuration from another peer session template.
show ip bgp neighbors
Displays information about the TCP and BGP connections to neighbors.
show ip bgp template peer-session
Displays locally configured peer session templates.
template peer-session
Creates a peer session template and enters session-template configuration mode.
neighbor maximum-prefix (BGP)
To control how many prefixes can be received from a neighbor, use the neighbor maximum-prefix command in router configuration mode. To disable this function, use the no form of this command.
neighbor { ip-address | peer-group-name } maximum-prefix maximum [threshold] [ restart restart-interval ] [warning-only]
no neighbor { ip-address | peer-group-name } maximum-prefix maximum
Syntax Description
ip-address
IP address of the neighbor.
peer-group-name
Name of a Border Gateway Protocol (BGP) peer group.
maximum
Maximum number of prefixes allowed from the specified neighbor. The number of prefixes that can be configured is limited only by the available system resources on a router.
threshold
(Optional) Integer specifying at what percentage of the maximum-prefix limit the router starts to generate a warning message. The range is from 1 to 100; the default is 75.
restart
(Optional) Configures the router that is running BGP to automatically reestablish a peering session that has been disabled because the maximum-prefix limit has been exceeded. The restart timer is configured with the restart-interval argument.
restart-interval
(Optional) Time interval (in minutes) that a peering session is reestablished. The range is from 1 to 65535 minutes.
warning-only
(optional) Allows the router to generate a sys-log message when the maximum-prefix limitis exceeded, instead of terminating the peering session.
Command Default
This command is disabled by default. Peering sessions are disabled when the maximum number of prefixes is exceeded. If the restart-interval argument is not configured, a disabled session will stay down after the maximum-prefix limit is exceeded.
threshold : 75 percent
Command History
Release
Modification
11.3
This command was introduced.
12.0(22)S
The restart keyword was introduced.
12.2(15)T
The restart keyword was integrated into Cisco IOS Release 12.2(15)T.
12.2(18)S
The restart keyword was integrated into Cisco IOS Release 12.2(18)S.
12.2(27)SBC
This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
15.2(4)S
This command was integrated into Cisco IOS Release 15.2(4)S.
Usage Guidelines
The neighbor maximum-prefixcommand allows you to configure a maximum number of prefixes that a Border Gateway Protocol (BGP) routing process will accept from the specified peer. This feature provides a mechanism (in addition to distribute lists, filter lists, and route maps) to control prefixes received from a peer.
When the number of received prefixes exceeds the maximum number configured, BGP disables the peering session (by default). If the restart keyword is configured, BGP will automatically reestablish the peering session at the configured time interval. If the restart keyword is not configured and a peering session is terminated because the maximum prefix limit has been exceed, the peering session will not be be reestablished until the clear ip bgp command is entered. If the warning-only keyword is configured, BGP sends only a log message and continues to peer with the sender.
There is no default limit on the number of prefixes that can be configured with this command. Limitations on the number of prefixes that can be configured are determined by the amount of available system resources.
Examples
In the following example, the maximum prefixes that will be accepted from the 192.168.1.1 neighbor is set to 1000:
Router(config)# router bgp 40000 Router(config-router)# network 192.168.0.0 Router(config-router)# neighbor 192.168.1.1 maximum-prefix 1000In the following example, the maximum number of prefixes that will be accepted from the 192.168.2.2 neighbor is set to 5000. The router is also configured to display warning messages when 50 percent of the maximum-prefix limit (2500 prefixes) has been reached.
Router(config)# router bgp 40000 Router(config-router)# network 192.168.0.0 Router(config-router)# neighbor 192.168.2.2 maximum-prefix 5000 50In the following example, the maximum number of prefixes that will be accepted from the 192.168.3.3 neighbor is set to 2000. The router is also configured to reestablish a disabled peering session after 30 minutes.
Router(config)# router bgp 40000 Router(config-router) network 192.168.0.0 Router(config-router)# neighbor 192.168.3.3 maximum-prefix 2000 restart 30In the following example, warning messages will be displayed when the threshold of the maximum-prefix limit (500 x 0.75 = 375) for the 192.168.4.4 neighbor is exceeded:
Router(config)# router bgp 40000 Router(config-router)# network 192.168.0.0 Router(config-router)# neighbor 192.168.4.4 maximum-prefix 500 warning-onlyneighbor peer-group (assigning members)
To configure a BGP neighbor to be a member of a peer group, use the neighbor peer-group command in address family or router configuration mode. To remove the neighbor from the peer group, use the noform of this command.
neighbor { ip-address | ipv6-address } peer-group peer-group-name
no neighbor { ip-address | ipv6-address } peer-group peer-group-name
Syntax Description
ip-address
IP address of the BGP neighbor that belongs to the peer group specified by the peer-group-name argument.
ipv6-address
IPv6 address of the BGP neighbor that belongs to the peer group specified by the peer-group-name argument.
peer-group-name
Name of the BGP peer group to which this neighbor belongs.
Command History
Release
Modification
11.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
12.2(2)T
Support for IPv6 was added.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 2.1
This command was introduced on Cisco ASR 1000 Series Routers.
Usage Guidelines
The neighbor at the IP address indicated inherits all the configured options of the peer group.
NoteUsing the no form of the neighbor peer-group command removes all of the BGP configuration for that neighbor, not just the peer group association.
Examples
The following router configuration mode example assigns three neighbors to the peer group named internal:
router bgp 100 neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source loopback 0 neighbor internal route-map set-med out neighbor internal filter-list 1 out neighbor internal filter-list 2 in neighbor 172.16.232.53 peer-group internal neighbor 172.16.232.54 peer-group internal neighbor 172.16.232.55 peer-group internal neighbor 172.16.232.55 filter-list 3 inThe following address family configuration mode example assigns three neighbors to the peer group named internal:
router bgp 100 address-family ipv4 unicast neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source loopback 0 neighbor internal route-map set-med out neighbor internal filter-list 1 out neighbor internal filter-list 2 in neighbor 172.16.232.53 peer-group internal neighbor 172.16.232.54 peer-group internal neighbor 172.16.232.55 peer-group internal neighbor 172.16.232.55 filter-list 3 inRelated Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
neighbor peer-group (creating)
Creates a BGP peer group.
neighbor shutdown
Disables a neighbor or peer group.
neighbor peer-group (creating)
To create a BGP or multiprotocol BGP peer group, use the neighbor peer-group command in address family or router configuration mode. To remove the peer group and all of its members, use the noform of this command.
Command History
Release
Modification
11.0
This command was introduced.
11.1(20)CC
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were added.
12.0(2)S
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were added.
12.0(7)T
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were removed.
Address family configuration mode was added.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Often in a BGP or multiprotocol BGP speaker, many neighbors are configured with the same update policies (that is, same outbound route maps, distribute lists, filter lists, update source, and so on). Neighbors with the same update policies can be grouped into peer groups to simplify configuration and make update calculation more efficient.
NotePeer group members can span multiple logical IP subnets, and can transmit, or pass along, routes from one peer group member to another.
Once a peer group is created with the neighbor peer-group command, it can be configured with the neighbor commands. By default, members of the peer group inherit all the configuration options of the peer group. Members also can be configured to override the options that do not affect outbound updates.
All the peer group members will inherit the current configuration as well as changes made to the peer group. Peer group members will always inherit the following configuration options by default:
- remote-as (if configured)
- version
- update-source
- outbound route-maps
- outbound filter-lists
- outbound distribute-lists
- minimum-advertisement-interval
- next-hop-self
If a peer group is not configured with a remote-as option, the members can be configured with the neighbor {ip-address | peer-group-name} remote-as command. This command allows you to create peer groups containing external BGP (eBGP) neighbors.
Examples
The following example configurations show how to create these types of neighbor peer group:
In the following example, the peer group named internal configures the members of the peer group to be iBGP neighbors. By definition, this is an iBGP peer group because the router bgp command and the neighbor remote-as command indicate the same autonomous system (in this case, autonomous system 100). All the peer group members use loopback 0 as the update source and use set-med as the outbound route map. The neighbor internal filter-list 2 in command shows that, except for 172.16.232.55, all the neighbors have filter list 2 as the inbound filter list.
router bgp 100 neighbor internal peer-group neighbor internal remote-as 100 neighbor internal update-source loopback 0 neighbor internal route-map set-med out neighbor internal filter-list 1 out neighbor internal filter-list 2 in neighbor 172.16.232.53 peer-group internal neighbor 172.16.232.54 peer-group internal neighbor 172.16.232.55 peer-group internal neighbor 172.16.232.55 filter-list 3 inThe following example defines the peer group named external-peers without the neighbor remote-as command. By definition, this is an eBGP peer group because each individual member of the peer group is configured with its respective autonomous system number separately. Thus the peer group consists of members from autonomous systems 200, 300, and 400. All the peer group members have the set-metric route map as an outbound route map and filter list 99 as an outbound filter list. Except for neighbor 172.16.232.110, all of them have 101 as the inbound filter list.
router bgp 100 neighbor external-peers peer-group neighbor external-peers route-map set-metric out neighbor external-peers filter-list 99 out neighbor external-peers filter-list 101 in neighbor 172.16.232.90 remote-as 200 neighbor 172.16.232.90 peer-group external-peers neighbor 172.16.232.100 remote-as 300 neighbor 172.16.232.100 peer-group external-peers neighbor 172.16.232.110 remote-as 400 neighbor 172.16.232.110 peer-group external-peers neighbor 172.16.232.110 filter-list 400 inIn the following example, all members of the peer group are multicast-capable:
router bgp 100 neighbor 10.1.1.1 remote-as 1 neighbor 172.16.2.2 remote-as 2 address-family ipv4 multicast neighbor mygroup peer-group neighbor 10.1.1.1 peer-group mygroup neighbor 172.16.2.2 peer-group mygroup neighbor 10.1.1.1 activate neighbor 172.16.2.2 activateRelated Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
clear ip bgp peer-group
Removes all the members of a BGP peer group.
show ip bgp peer-group
Displays information about BGP peer groups.
neighbor prefix-list
To prevent distribution of Border Gateway Protocol (BGP) neighbor information as specified in a prefix list, a Connectionless Network Service (CLNS) filter expression, or a CLNS filter set, use the neighbor prefix-list command in address family or router configuration mode. To remove a filter list, use the no form of this command.
neighbor { ip-address | peer-group-name } prefix-list { prefix-list-name | clns-filter-expr-name | clns-filter-set-name } { in | out }
no neighbor { ip-address | peer-group-name } prefix-list { prefix-list-name | clns-filter-expr-name | clns-filter-set-name } { in | out }
Syntax Description
ip-address
IP address of neighbor.
peer-group-name
Name of a BGP peer group.
prefix-list-name
Name of a prefix list. This argument is used only under router configuration mode.
clns-filter-expr-name
Name of a CLNS filter expression. This argument is used only under network service access point (NSAP) address family configuration mode.
clns-filter-set-name
Name of a CLNS filter set. This argument is used only under NSAP address family configuration mode.
in
Filter list is applied to incoming advertisements from that neighbor.
out
Filter list is applied to outgoing advertisements to that neighbor.
Command History
Release
Modification
12.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
12.2(8)T
Under address family configuration mode, the prefix-list-nameargument was amended to specify the name of a CLNS filter expression or a CLNS filter set.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE 2.6
This command was integrated into Cisco IOS XE Release 2.6.
Usage Guidelines
Using prefix lists is one of three ways to filter BGP advertisements. You can also use AS-path filters, defined with the ip as-path access-list global configuration command and used in the neighbor filter-list command to filter BGP advertisements. The third way to filter BGP advertisements uses access or prefix lists with the neighbor distribute-listcommand.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command. Specifying the command with an IP address will override the value inherited from the peer group.
Use the neighbor prefix-list command in address family configuration mode to filter NSAP BGP advertisements.
NoteDo not apply both a neighbor distribute-list and a neighbor prefix-list command to a neighbor in any given direction (inbound or outbound). These two commands are mutually exclusive, and only one command (neighbor distribute-listor neighbor prefix-list) can be applied to each inbound or outbound direction.
Examples
The following router configuration mode example applies the prefix list named abc to incoming advertisements from neighbor 10.23.4.1:
router bgp 65200 network 192.168.1.2 neighbor 10.23.4.1 prefix-list abc inThe following address family configuration mode example applies the prefix list named abc to incoming advertisements from neighbor 10.23.4.2:
router bgp 65001 address-family ipv4 unicast network 192.168.2.4 neighbor 10.23.4.2 prefix-list abc inThe following router configuration mode example applies the prefix list named CustomerA to outgoing advertisements to neighbor 10.23.4.3:
router bgp 64800 network 192.168.3.6 neighbor 10.23.4.3 prefix-list CustomerA outThe following address family configuration mode example applies the CLNS filter list set named default-prefix-only to outbound advertisements to neighbor 10.1.2.1:
clns filter-set default-prefix-only deny 49... clns filter-set default-prefix-only permit default ! router bgp 65202 address-family nsap neighbor 10.1.2.1 activate neighbor 10.1.2.1 default-originate neighbor 10.1.2.1 prefix-list default-prefix-only outRelated Commands
Command
Description
address-family ipv4 (BGP)
Enters the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Enters the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
clear ip prefix-list
Resets the hit count of the prefix list entries.
clns filter-expr
Creates an entry in a CLNS filter expression.
clns filter-set
Creates an entry in a CLNS filter set.
ip as-path access-list
Defines a BGP-related access list.
ip prefix-list
Creates an entry in a prefix list.
ip prefix-list description
Adds a text description of a prefix list.
ip prefix-list sequence-number
Enables the generation of sequence numbers for entries in a prefix list.
neighbor filter-list
Sets up a BGP filter.
show bgp nsap filter-list
Displays information about a filter list or filter list entries.
show ip bgp peer-group
Displays information about BGP peer groups.
show ip prefix-list
Displays information about a prefix list or prefix list entries.
neighbor remote-as
To add an entry to the BGP or multiprotocol BGP neighbor table, use the neighbor remote-as command in router configuration mode. To remove an entry from the table, use the no form of this command.
neighbor { ip-address | ipv6-address% | peer-group-name } remote-as autonomous-system-number [ alternate-as autonomous-system-number ... ]
no neighbor { ip-address | ipv6-address% | peer-group-name } remote-as autonomous-system-number [ alternate-as autonomous-system-number ... ]
Syntax Description
Command History
Release
Modification
10.0
This command was introduced.
11.0
The peer-group-name argument was added.
11.1(20)CC
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were added.
12.0(7)T
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were removed.
12.2(4)T
Support for the IPv6 address family was added.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
This command was modified. The % keyword was added.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH. The alternate-as keyword was added to support BGP dynamic neighbors.
12.2(33)SB
This command was integrated into Cisco IOS Release 12.2(33)SB.
Cisco IOS XE Release 2.1
This command was introduced on Cisco ASR 1000 Series Routers.
12.0(32)S12
This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
12.0(32)SY8
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.4(24)T
This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
Cisco IOS XE Release 2.3
This command was modified. Support for 4-byte autonomous system numbers in asdot notation only was added.
12.2(33)SXI1
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.0(33)S3
This command was modified. Support for asplain notation was added and the default format for 4-byte autonomous system numbers is now asplain.
Cisco IOS XE Release 2.4
This command was modified. Support for asplain notation was added and the default format for 4-byte autonomous system numbers is now asplain.
12.2(33)SRE
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
12.2(33)XNE
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
15.0(1)S
This command was integrated into Cisco IOS Release 15.0(1)S.
15.1(1)SG
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
Cisco IOS XE Release 3.3SG
This command was modified. Support for 4-byte autonomous system numbers in asplain and asdot notation was added.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.
15.2(1)E
This command was integrated into Cisco IOS Release 15.2(1)E.
Usage Guidelines
Specifying a neighbor with an autonomous system number that matches the autonomous system number specified in the router bgp global configuration command identifies the neighbor as internal to the local autonomous system. Otherwise, the neighbor is considered external.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.
By default, neighbors that are defined using the neighbor remote-as command in router configuration mode exchange only unicast address prefixes. To exchange other address prefix types, such as multicast and Virtual Private Network (VPN) Version 4, neighbors must also be activated in the appropriate address family configuration mode.
Use the alternate-as keyword introduced in Cisco IOS Release 12.2(33)SXH to specify up to five alternate autonomous systems in which a dynamic BGP neighbor may be identified. BGP dynamic neighbor support allows BGP peering to a group of remote neighbors that are defined by a range of IP addresses. BGP dynamic neighbors are configured using a range of IP addresses and BGP peer groups. After a subnet range is configured and associated with a BGP peer group using the bgp listen command and a TCP session is initiated for an IP address in the subnet range, a new BGP neighbor is dynamically created as a member of that group. The new BGP neighbor will inherit any configuration or templates for the group.
The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces. This keyword does not need to be used for non-link-local IPv6 addresses.
In Cisco IOS Release 12.0(32)SY8, 12.0(33)S3, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, Cisco IOS XE Release 2.4, and later releases, the Cisco implementation of 4-byte autonomous system numbers uses asplain--65538 for example--as the default regular expression match and output display format for autonomous system numbers, but you can configure 4-byte autonomous system numbers in both the asplain format and the asdot format as described in RFC 5396. To change the default regular expression match and output display of 4-byte autonomous system numbers to asdot format, use the bgp asnotation dot command followed by the clear ip bgp * command to perform a hard reset of all current BGP sessions.
In Cisco IOS Release 12.0(32)S12, 12.4(24)T, and Cisco IOS XE Release 2.3, the Cisco implementation of 4-byte autonomous system numbers uses asdot--1.2 for example--as the only configuration format, regular expression match, and output display, with no asplain support.
NoteIn Cisco IOS releases that include 4-byte ASN support, command accounting and command authorization that include a 4-byte ASN number are sent in the asplain notation irrespective of the format that is used on the command-line interface.
To ensure a smooth transition, we recommend that all BGP speakers within an autonomous system that is identified using a 4-byte autonomous system number, be upgraded to support 4-byte autonomous system numbers.
Examples
The following example specifies that a router at the address 10.108.1.2 is an internal BGP (iBGP) neighbor in autonomous system number 65200:
router bgp 65200 network 10.108.0.0 neighbor 10.108.1.2 remote-as 65200The following example specifies that a router at the IPv6 address 2001:0DB8:1:1000::72a is an external BGP (eBGP) neighbor in autonomous system number 65001:
router bgp 65300 address-family ipv6 vrf site1 neighbor 2001:0DB8:1:1000::72a remote-as 65001The following example assigns a BGP router to autonomous system 65400, and two networks are listed as originating in the autonomous system. Then the addresses of three remote routers (and their autonomous systems) are listed. The router being configured will share information about networks 10.108.0.0 and 192.168.7.0 with the neighbor routers. The first router is a remote router in a different autonomous system from the router on which this configuration is entered (an eBGP neighbor); the second neighbor remote-as command shows an internal BGP neighbor (with the same autonomous system number) at address 10.108.234.2; and the last neighbor remote-as command specifies a neighbor on a different network from the router on which this configuration is entered (also an eBGP neighbor).
router bgp 65400 network 10.108.0.0 network 192.168.7.0 neighbor 10.108.200.1 remote-as 65200 neighbor 10.108.234.2 remote-as 65400 neighbor 172.29.64.19 remote-as 65300The following example configures neighbor 10.108.1.1 in autonomous system 65001 to exchange only multicast routes:
router bgp 65001 neighbor 10.108.1.1 remote-as 65001 neighbor 172.31 1.2 remote-as 65001 neighbor 172.16.2.2 remote-as 65002 address-family ipv4 multicast neighbor 10.108.1.1 activate neighbor 172.31 1.2 activate neighbor 172.16.2.2 activate exit-address-familyThe following example configures neighbor 10.108.1.1 in autonomous system 65001 to exchange only unicast routes:
router bgp 65001 neighbor 10.108.1.1 remote-as 65001 neighbor 172.31 1.2 remote-as 65001 neighbor 172.16.2.2 remote-as 65002The following example, configurable only in Cisco IOS Release 12.2(33)SXH and later releases, configures a subnet range of 192.168.0.0/16 and associates this listen range with a BGP peer group. Note that the listen range peer group that is configured for the BGP dynamic neighbor feature can be activated in the IPv4 address family using the neighbor activate command. After the initial configuration on Router 1, when Router 2 starts a BGP router session and adds Router 1 to its BGP neighbor table, a TCP session is initiated, and Router 1 creates a new BGP neighbor dynamically because the IP address of the new neighbor is within the listen range subnet.
Examples
enable configure terminal router bgp 45000 bgp log-neighbor-changes neighbor group192 peer-group bgp listen range 192.168.0.0/16 peer-group group192 neighbor group192 remote-as 40000 alternate-as 50000 address-family ipv4 unicast neighbor group192 activate endExamples
enable configure terminal router bgp 50000 neighbor 192.168.3.1 remote-as 45000 exitIf the show ip bgp summary command is now entered on Router 1, the output shows the dynamically created BGP neighbor, 192.168.3.2.
Router1# show ip bgp summary BGP router identifier 192.168.3.1, local AS number 45000 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd *192.168.3.2 4 50000 2 2 0 0 0 00:00:37 0 * Dynamically created based on a listen range command Dynamically created neighbors: 1/(200 max), Subnet ranges: 1 BGP peergroup group192 listen range group members: 192.168.0.0/16The following example configures a BGP process for autonomous system 65538 and configures two external BGP neighbors in different autonomous systems using 4-byte autonomous system numbers in asplain format. This example is supported only on Cisco IOS Release 12.0(32)SY8, 12.0(33)S3, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, Cisco IOS XE Release 2.4, or later releases.
router bgp 65538 neighbor 192.168.1.2 remote-as 65536 neighbor 192.168.3.2 remote-as 65550 neighbor 192.168.3.2 description finance ! address-family ipv4 neighbor 192.168.1.2 activate neighbor 192.168.3.2 activate no auto-summary no synchronization network 172.17.1.0 mask 255.255.255.0 exit-address-familyThe following example configures a BGP process for autonomous system 1.2 and configures two external BGP neighbors in different autonomous systems using 4-byte autonomous system numbers in asdot format. This example requires Cisco IOS Release 12.0(32)SY8, 12.0(32)S12, 12.2(33)SRE, 12.2(33)XNE, 12.2(33)SXI1, 12.4(24)T, Cisco IOS XE Release 2.3, or a later release.
router bgp 1.2 neighbor 192.168.1.2 remote-as 1.0 neighbor 192.168.3.2 remote-as 1.14 neighbor 192.168.3.2 description finance ! address-family ipv4 neighbor 192.168.1.2 activate neighbor 192.168.3.2 activate no auto-summary no synchronization network 172.17.1.0 mask 255.255.255.0 exit-address-familyRelated Commands
Command
Description
bgp asnotation dot
Changes the default display and the regular expression match format of BGP 4-byte autonomous system numbers from asplain (decimal values) to dot notation.
bgp listen
Associates a subnet range with a BGP peer group and activates the BGP dynamic neighbors feature.
neighbor peer-group
Creates a BGP peer group.
router bgp
Configures the BGP routing process.
neighbor route-map
To apply a route map to incoming or outgoing routes, use the neighbor route-map command in address family or router configuration mode. To remove a route map, use the no form of this command.
neighbor { ip-address | peer-group-name | ipv6-address [ % ] } route-map map-name { in | out }
no neighbor { ip-address | peer-group-name | ipv6-address [ % ] } route-map map-name { in | out }
Syntax Description
ip-address
IP address of the neighbor.
peer-group-name
Name of a BGP or multiprotocol BGP peer group.
ipv6-address
IPv6 address of the neighbor.
%
(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.
map-name
Name of a route map.
in
Applies route map to incoming routes.
out
Applies route map to outgoing routes.
Command History
Release
Modification
10.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
12.2(4)T
Support for IPv6 was added.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
The % keyword was added.
12.2(33)SB
This command was integrated into Cisco IOS Release 12.2(33)SB.
Cisco IOS XE Release 2.1
This command was introduced on Cisco ASR 1000 Series Routers.
12.2(33)SXI
This command was integrated into Cisco IOS Release 12.2(33)SXI.
Usage Guidelines
When specified in address family configuration mode, this command applies a route map to that particular address family only. When specified in router configuration mode, this command applies a route map to IPv4 or IPv6 unicast routes only.
If an outbound route map is specified, it is proper behavior to only advertise routes that match at least one section of the route map.
If you specify a BGP or multiprotocol BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command. Specifying the command for a neighbor overrides the inbound policy that is inherited from the peer group.
The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces. This keyword does not need to be used for non-link-local IPv6 addresses.
Examples
The following router configuration mode example applies a route map named internal-map to a BGP incoming route from 172.16.70.24:
router bgp 5 neighbor 172.16.70.24 route-map internal-map in route-map internal-map match as-path 1 set local-preference 100The following address family configuration mode example applies a route map named internal-map to a multiprotocol BGP incoming route from 172.16.70.24:
router bgp 5 address-family ipv4 multicast neighbor 172.16.70.24 route-map internal-map in route-map internal-map match as-path 1 set local-preference 100Related Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IP Version 4 address prefixes.
address-family ipv6
Enters address family configuration mode for configuring routing sessions such as BGP that use standard IPv6 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPN Version 4 address prefixes.
address-family vpnv6
Places the router in address family configuration mode for configuring routing sessions that use standard VPNv6 address prefixes.
neighbor remote-as
Creates a BGP peer group.
neighbor shutdown
To disable a neighbor or peer group or to gracefully shut down a link for maintenance, use the neighbor shutdown command in router configuration mode or address family configuration mode. To reenable the neighbor or peer group, use the no form of this command.
neighbor { ip-address | peer-group-name } shutdown graceful seconds [ community value] [ local-preference value ] [ community value ] [ local-preference value]
no neighbor { ip-address | peer-group-name } shutdown graceful seconds [ community value] [ local-preference value ] [ community value ] [ local-preference value]
Syntax Description
Command History
Release
Modification
12.0
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
15.2(2)S
This command was modified. The graceful seconds keyword and argument, the community value keyword and argument, and the local-preference value keyword and argument were added.
Cisco IOS XE 3.6S
This command was modified. The graceful seconds keyword and argument, the community value keyword and argument, and the local-preference value keyword and argument were added.
Cisco IOS XE 3.7S
This command was implemented on the Cisco ASR 903 router.
15.2(4)M
This command was integrated into Cisco IOS Release 15.2(4)M.
15.2(4)S
This command was implemented on the Cisco 7200 series router.
Usage Guidelines
The neighbor shutdown command terminates any active session for the specified neighbor or peer group and removes all associated routing information. In the case of a peer group, a large number of peering sessions could be terminated suddenly.
To display a summary of BGP neighbors and peer group connections, use the show ip bgp summary command. Those neighbors with an Idle status and the Admin entry have been disabled by the neighbor shutdown command.
“State/PfxRcd” shows the current state of the BGP session or the number of prefixes the router has received from a neighbor or peer group. When the maximum number (as set by the neighbor maximum-prefix command) is reached, the string “PfxRcd” appears in the entry, the neighbor is shut down, and the connection is idle.
BGP Graceful Shutdown
Use the BGP Graceful Shutdown feature to shut down a link for planned, manual, maintenance operations and thereby reduce or eliminate packet loss. The feature can be configured globally (for all address families) or for the IPv4 VRF or IPv6 VRF address family.
Keep in mind that you should configure adequate time to allow iBGP peers to converge and to choose an alternate path as the best path. BGP will not prevent a network administrator from specifying too low a number of seconds, in which case there might not be enough time for graceful shutdown to occur.
If you use the graceful keyword, you must also configure at least one of the community or local-preference keywords. You may use both the community and local-preference keywords.
During graceful shutdown timer, there is no nvgen. There will be nvgen of the neighbor shutdown command only after the shutdown.
neighbor ip-address shutdown graceful seconds local-pref value community value
Once the graceful shutdown timer expires, the command will be nvgened as follows:
neighbor ip-address shutdown
If you reset the sessions using the clear ip bgp command, all timers will be reset. Therefore, there will be no graceful shutdown.
Examples
The following example disables any active session for the neighbor 172.16.70.23:
neighbor 172.16.70.23 shutdownThe following example disables all peering sessions for the peer group named internal:
neighbor internal shutdownThe following example configures the specified neighbor to be gracefully shut down in 1200 seconds and advertises the route with the well-known GSHUT community and a local preference of 400:
neighbor 2001:db8:a::1 shutdown graceful 1200 local-preference 400neighbor soft-reconfiguration
To configure the Cisco IOS software to start storing updates, use the neighbor soft-reconfiguration command in router configuration mode. To not store received updates, use the noform of this command.
neighbor { ip-address | peer-group-name } soft-reconfiguration inbound
no neighbor { ip-address | peer-group-name } soft-reconfiguration inbound
Command History
Release
Modification
11.2
This command was introduced.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Entering this command starts the storage of updates, which is required to do inbound soft reconfiguration. Outbound BGP soft reconfiguration does not require inbound soft reconfiguration to be enabled.
To use soft reconfiguration, or soft reset, without preconfiguration, both BGP peers must support the soft route refresh capability, which is advertised in the open message sent when the peers establish a TCP session. Routers running Cisco IOS software releases prior to Release 12.1 do not support the route refresh capability and must clear the BGP session using the neighbor soft-reconfiguration command. Clearing the BGP session using the neighbor soft-reconfiguration command has a negative effect on network operations and should only be used as a last resort. Routers running Cisco IOS software Release 12.1 or later releases support the route refresh capability and dynamic soft resets, and can use the clear ip bgp{*| address| peer-group name} in command to clear the BGP session.
To determine whether a BGP router supports this capability, use the show ip bgp neighborscommand. If a router supports the route refresh capability, the following message is displayed:
Received route refresh capability from peer.If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.
Examples
The following example enables inbound soft reconfiguration for the neighbor 10.108.1.1. All the updates received from this neighbor will be stored unmodified, regardless of the inbound policy. When inbound soft reconfiguration is done later, the stored information will be used to generate a new set of inbound updates.
router bgp 100 neighbor 10.108.1.1 remote-as 200 neighbor 10.108.1.1 soft-reconfiguration inboundneighbor unsuppress-map
To selectively advertise routes previously suppressed by the aggregate-address command, use the neighbor unsuppress-map command in address family or router configuration mode. To restore the system to the default condition, use the no form of this command.
neighbor { ip-address | peer-group-name } unsuppress-map route-map-name
no neighbor { ip-address | peer-group-name } unsuppress-map route-map-name
Command History
Release
Modification
12.0(5)T
This command was introduced.
12.0(5)T
Address family configuration mode was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
Use of the neighbor unsuppress-map command allows specified suppressed routes to be advertised.
Examples
The following BGP router configuration shows that routes specified by a route map named map1 are suppressed:
access-list 3 deny 172.16.16.6 access-list 3 permit any route-map map1 permit 10 match ip address 3 ! router bgp 65000 network 172.16.0.0 neighbor 192.168.1.2 remote-as 40000 aggregate-address 172.0.0.0 255.0.0.0 suppress-map map1 neighbor 192.168.1.2 unsuppress-map map1 neighbor 192.168.1.2 activateThe following example shows the routes specified by internal-map being unsuppressed for neighbor 172.16.16.6:
router bgp 100 address-family ipv4 multicast network 172.16.0.0 neighbor 172.16.16.6 unsuppress-map internal-mapRelated Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4
Places the routing in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
aggregate-address
Creates an aggregate entry in a BGP routing table.
neighbor route-map
Applies a route map to inbound or outbound routes.
neighbor update-source
To have the Cisco software allow Border Gateway Protocol (BGP) sessions to use any operational interface for TCP connections, use the neighbor update-source command in router configuration mode. To restore the interface assignment to the closest interface, which is called the best local address, use the no form of this command.
neighbor { ip-address | ipv6-address [ % ] | peer-group-name } update-source interface-type interface-number
neighbor { ip-address | ipv6-address [ % ] | peer-group-name } update-source interface-type interface-number
Syntax Description
ip-address
IPv4 address of the BGP-speaking neighbor.
ipv6-address
IPv6 address of the BGP-speaking neighbor.
%
(Optional) IPv6 link-local address identifier. This keyword needs to be added whenever a link-local IPv6 address is used outside the context of its interface.
peer-group-name
Name of a BGP peer group.
interface-type
Interface type.
interface-number
Interface number.
Command History
Release
Modification
10.0
This command was introduced.
12.2(4)T
The ipv6-address argument was added.
12.0(21)ST
This command was integrated into Cisco IOS Release 12.0(21)ST.
12.0(22)S
This command was integrated into Cisco IOS Release 12.0(22)S.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
The % keyword was added.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Cisco IOS XE Release 2.1
This command was introduced on Cisco ASR 1000 series routers.
15.1(2)SNG
This command was implemented on the Cisco ASR 901 Series Aggregation Services Routers.
Usage Guidelines
This command can work in conjunction with the loopback interface feature described in the “Interface Configuration Overview” chapter of the Cisco IOS Interface and Hardware Component Configuration Guide.
If you specify a BGP peer group by using the peer-group-name argument, all the members of the peer group will inherit the characteristic configured with this command.
The neighbor update-source command must be used to enable IPv6 link-local peering for internal or external BGP sessions.
The % keyword is used whenever link-local IPv6 addresses are used outside the context of their interfaces and for these link-local IPv6 addresses you must specify the interface they are on. The syntax becomes <IPv6 local-link address>%<interface name>, for example, FE80::1%Ethernet1/0. Note that the interface type and number must not contain any spaces, and be used in full-length form because name shortening is not supported in this situation. The % keyword and subsequent interface syntax is not used for non-link-local IPv6 addresses.
Examples
The following example sources BGP TCP connections for the specified neighbor with the IP address of the loopback interface rather than the best local address:
router bgp 65000 network 172.16.0.0 neighbor 172.16.2.3 remote-as 110 neighbor 172.16.2.3 update-source Loopback0The following example sources IPv6 BGP TCP connections for the specified neighbor in autonomous system 65000 with the global IPv6 address of loopback interface 0 and the specified neighbor in autonomous system 65400 with the link-local IPv6 address of Fast Ethernet interface 0/0. Note that the link-local IPv6 address of FE80::2 is on Ethernet interface 1/0.
router bgp 65000 neighbor 3ffe::3 remote-as 65000 neighbor 3ffe::3 update-source Loopback0 neighbor fe80::2%Ethernet1/0 remote-as 65400 neighbor fe80::2%Ethernet1/0 update-source FastEthernet 0/0 address-family ipv6 neighbor 3ffe::3 activate neighbor fe80::2%Ethernet1/0 activate exit-address-familynetwork (BGP and multiprotocol BGP)
To specify the networks to be advertised by the Border Gateway Protocol (BGP) and multiprotocol BGP routing processes, use the network command in address family or router configuration mode. To remove an entry from the routing table, use the no form of this command.
network { network-number [ mask network-mask ] | nsap-prefix } [ route-map map-tag ]
no network { network-number [ mask network-mask ] | nsap-prefix } [ route-map map-tag ]
Syntax Description
network-number
Network that BGP or multiprotocol BGP will advertise.
mask network-mask
(Optional) Network or subnetwork mask with mask address.
nsap-prefix
Network service access point (NSAP) prefix of the Connectionless Network Service (CLNS) network that BGP or multiprotocol BGP will advertise. This argument is used only under NSAP address family configuration mode.
route-map map-tag
(Optional) Identifier of a configured route map. The route map should be examined to filter the networks to be advertised. If not specified, all networks are advertised. If the keyword is specified, but no route map tags are listed, no networks will be advertised.
Command History
Release
Modification
10.0
This command was introduced.
12.0
The limit of 200 network commands per BGP router was removed.
11.1(20)CC
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were added.
12.0(7)T
The nlri unicast, nlri multicast, and nlri unicast multicast keywords were removed.
Address family configuration mode was added.
12.2(8)T
The nsap-prefix argument was added to address family configuration mode.
12.2(25)SG
This command was integrated into Cisco IOS Release 12.2(25)SG.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
Cisco IOS XE 2.6
This command was integrated into Cisco IOS XE Release 2.6.
Usage Guidelines
BGP and multiprotocol BGP networks can be learned from connected routes, from dynamic routing, and from static route sources.
The maximum number of network commands you can use is determined by the resources of the router, such as the configured NVRAM or RAM.
Examples
The following example sets up network 10.108.0.0 to be included in the BGP updates:
router bgp 65100 network 10.108.0.0The following example sets up network 10.108.0.0 to be included in the multiprotocol BGP updates:
router bgp 64800 address family ipv4 multicast network 10.108.0.0The following example advertises NSAP prefix 49.6001 in the multiprotocol BGP updates:
router bgp 64500 address-family nsap network 49.6001Related Commands
Command
Description
address-family ipv4 (BGP)
Enters the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IP Version 4 address prefixes.
address-family vpnv4
Enters the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
default-information originate (BGP)
Allows the redistribution of network 0.0.0.0 into BGP.
route-map (IP)
Defines the conditions for redistributing routes from one routing protocol into another.
router bgp
Configures the BGP routing process.
network backdoor
To specify a backdoor route to a BGP-learned prefix that provides better information about the network, use the network backdoor command in address family or router configuration mode. To remove an address from the list, use the no form of this command.
Command History
Release
Modification
10.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX
This command is supported in the Cisco IOS Release 12.2SX train. Support in a specific 12.2SX release of this train depends on your feature set, platform, and platform hardware.
Usage Guidelines
A backdoor network is assigned an administrative distance of 200. The objective is to make Interior Gateway Protocol (IGP) learned routes preferred. A backdoor network is treated as a local network, except that it is not advertised. A network that is marked as a back door is not sourced by the local router, but should be learned from external neighbors. The BGP best path selection algorithm does not change when a network is configured as a back door.
Examples
The following address family configuration example configures network 10.108.0.0 as a local network and network 192.168.7.0 as a backdoor network:
router bgp 109 address-family ipv4 multicast network 10.108.0.0 network 192.168.7.0 backdoorThe following router configuration example configures network 10.108.0.0 as a local network and network 192.168.7.0 as a backdoor network:
router bgp 109 network 10.108.0.0 network 192.168.7.0 backdoorRelated Commands
Command
Description
address-family ipv4 (BGP)
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IP Version 4 address prefixes.
address-family vpnv4
Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPN Version 4 address prefixes.
distance bgp
Allows the use of external, internal, and local administrative distances that could be a better route to a node.
network (BGP and multiprotocol BGP)
Specifies networks to be advertised by the BGP and multiprotocol BGP routing processes.
router bgp
Assigns an absolute weight to a BGP network.
