To enable Cisco Express Forwarding table consistency checker types and parameters, use the ceftableconsistency-check command in global configuration mode. To disable consistency checkers, use the no form of this command.
On the Cisco 10000 series routers, IPv6 is supported on Cisco IOS Release 12.2(28)SB and later releases.
type
(Optional) Specifies the type of consistency check to enable.
lc-detect
(Optional) (Distributed platforms such as the Cisco 7500 series only) Detects missing prefixes on the line card. The information is confirmed by the Route Switch Processor (RSP).
This consistency checker operates on the line card by retrieving IP prefixes that are missing from its Forwarding Information Base (FIB) table. If IP prefixes are missing, the line card cannot forward packets for these addresses. This consistency checker then sends IP prefixes to the RSP for confirmation. If the RSP detects that it has the relevant entry, an inconsistency is detected, and an error message is displayed. Finally, the RSP sends a signal back to the line card confirming that the IP prefix is an inconsistency.
scan-lc-rp
(Optional) (Distributed platforms only) Performs a passive scan check of tables on the line card.
This consistency checker operates on the line card by examining the FIB table for a configurable time period and sending the next x prefixes to the RSP. The RSP does an exact lookup, and if it finds the prefix missing, it reports an inconsistency. Finally, the RSP sends a signal back to the line card for confirmation.
scan-rp-lc
(Optional) Operates on the RSP (opposite of the scan-lc-rp consistency checker) by examining the FIB table for a configurable time period and sending the next x prefixes to the line card.
The line card does an exact lookup. If it finds the prefix missing, the line card reports an inconsistency and signals the RSP for confirmation.
scan-rib-ios
(Optional) Compares the Routing Information Base (RIB) to the FIB table and provides the number of entries missing from the FIB table.
scan-ios-rib
(Optional) Compares the FIB table to the RIB and provides the number of entries missing from the RIB.
countcount-number
(Optional) Specifies the maximum number of prefixes to check per scan. The range is from 2 to 10000. The default count number is 1000 prefixes per scan for thescan-rib-ios and scan-ios-rib keywords. The default count number is 0 for the lc-detect, scan-lc-rp, and scan-rp-lc keywords.
periodseconds
(Optional) Period between scans. Valid values are from 30 to 3600 seconds. The default is 60 seconds.
error-message
(Optional) Enables the consistency checker to generate an error message when it detects an inconsistency. By default, this function is disabled.
auto-repair
(Optional) Enables the auto repair function. By default, this function is enabled. You can enter the no form of the command to disable auto repair or enter the default form of the command to return the auto repair settings to a 10-second delay and 300-second holddown.
delayseconds
(Optional) Specifies how long the consistency checker waits to fix an inconsistency. The range is 10 to 300 seconds. The default delay is 10 seconds.
holddownseconds
(Optional) Specifies how long the consistency checker waits to reenable auto repair after auto repair runs. The range is from 300 to 3000 seconds. The default delay is 300 seconds.
data-checking
(Optional) Enables the consistency checker data-checking utility. By default, this function is disabled.
Command Default
All consistency checkers are disabled.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(25)S
This command was introduced. This command replaces the ipceftableconsistency-check command.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Cisco IOS XE Release 2.1
This command was integrated into Cisco IOS XE Release 2.1 and implemented on the Cisco ASR 1000 Series Aggregation Services Router.
Examples
The following example enables the Cisco Express Forwarding consistency checker to check IPv4 addresses:
Router(config)# cef table consistency-check ipv4
The following example enables the Cisco Express Forwarding consistency checker to check IPv4 addresses and specifies the scan-rp-lc checker to run every 60 seconds for 5000 prefixes:
Router(config)# cef table consistency-check ipv4 type scan-rp-lc count 5000 period 60
The following example enables the Cisco Express Forwarding consistency checker to check IPv4 addresses and display an error message when it finds an inconsistency:
Displays Cisco Express Forwarding IP prefix inconsistencies.
cef table download
To set download characteristics for prefixes or routes in the Cisco Express Forwarding table, use the
ceftabledownload command in global configuration mode. To return to the default download characteristics, use the
no form of this command.
Any route not matched, which include Internet routes. The default priority is 4.
connected-route
Route directly connected to the router. The default priority is 2.
default-route
Default route, 0.0.0.0/0 or ::/0. The default priority is 1.
receive-route
Receive route, local address on router. The default priority is 2.
recursive-dependents
Route with recursive dependents, matches next-hop of other recursive routes. The default priority is 1.
route-in-vrf
Route in a Virtual Private Network (VPN) routing and forwarding (VRF) table. The default priority is 3.
priority
Sets the table download priority.
priority-number
Select one of the following as the priority number:
1--1st priority
2--2nd priority
3--3rd priority
4--4th priority
Command Default
The default download characteristics apply to routes and prefixes downloaded from the Route Processor (RP) to the line cards.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(33)SRE
This command was introduced.
Usage Guidelines
Use this command to change the priority of how prefixes and routes in the Cisco Express Forwarding table are downloaded from the RP to the line cards.
Default download priorities are set up to improve convergence when topology changes occur in networks of distributed platform, such as the Cisco 7600 series routers and the Cisco Catalyst 6000 series switches.
Prefixes and routes are categorized and downloaded at four different priorities. The table below lists the download priority and the associated prefix or route type.
Table 1 Download Priorities and Associated Prefix or Route Category
Download Priority
Prefix or Route Type
Priority 1 (P1)
Default routes
Routes with recursive dependents, typically Interior Gateway Protocol (IGP) prefixes that are the next hop of internal Border Gateway Protocol (iBGP) learned routes
Priority 2 (P2)
Directly connected routes
Receive routes; that is, the host routes for the interface address of the router
Priority 3 (P3)
Any route in a VRF table
Priority 4 (P4)
Any other route
In a typical network, a small number of IGP prefixes have many iBGP prefixes recursing through them. When an IGP topology change occurs, the key to updating the forwarding of the iBGP prefixes is to update the IGP prefix through which they recurse. If these prefixes with recursing dependents are downloaded before other prefixes, convergence will be faster. Therefore, the default priority for routes with recursive dependents is P1.
Prioritizing the download of directly connected prefixes and their associated local interface address allows for faster and more deterministic failure detection when an interface goes down. In addition, traffic is received at the local interface addresses as soon as possible, which allows for faster Layer 3 protocol convergence. The default priority for directly connected and receive routes is set at P2.
VRF routes over global table routes or Internet routes have a default priority of P3, and all other routes are prioritized at P4.
The
ceftabledownload command allows you to override a default priority so you can customize prefix and route downloads from the RP to the line cards. To display the configured download priority, use the
showceftabledownloadpriority command.
Examples
The following example shows how to change the download priority of the default route from P1 to P2:
Displays the configured download priority of Cisco Express Forwarding routes.
cef table output-chain build
To configure characteristics for Cisco Express Forwarding table output chain building for the forwarding of packets through the network, use the ceftableoutput-chainbuildcommand in global configuration mode. To disable Cisco Express Forwarding table output chain-building characteristics, use the no form of this command. To restore the general Cisco Express Forwarding table output chain-building characteristics to their default values, use either the default form of this command.
Configures a faster convergence speed for table output chain building.
memory-utilization
Configures less memory use for table output chain building.
default
Removes any table output chain building characteristic.
indirection
Enables insertion of indirection objects for table output chain building.
non-recursive-prefix
(Optional) Enables insertion of indirection objects for nonrecursive prefixes.
recursive-prefix
(Optional) Enables insertion of indirection objects for recursive prefixes.
inplace-modify
Enables in-place modification of objects in the forwarding chain.
load-sharing
(Optional) Enables in-place modification of load-balancing objects in the forwarding chain.
push-counter
(Optional) Enables in-place modification of packet counters in the output chain.
Command Default
Convergence speed and indirection characteristics are enabled by default for the building of Cisco Express Forwarding table output chains.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(33)SRA
This command was introduced.
12.2(33)SB
This command was integrated into Cisco IOS Release 12.2(33)SB.
12.2(33)SXH
This command was integrated into Cis IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
General Characteristics
Use the ceftableoutput-chainbuildfavor command to override the Cisco Express Forwarding table default operational behavior used to build output chains for forwarding of network traffic.
The default behavior for output chain building favors convergence, if this behavior is permitted by the platform. (See your platform documentation for information on the convergence of recursive and nonrecursive prefixes.) Depending on your network requirements and resources, you might choose to do one of the following:
Use the convergence-speedkeyword to increase convergence speed, which requires additional system resources, especially additional memory.
Use the memory-utilizationkeyword to decrease memory use, which decreases convergence speed and uses fewer system resources.
The default is platform-specific and usually sufficient. The default falls between the options provided for your use with this command.
For all ceftableoutput-chainbuildcommands, the state is enabled, disabled, or use the system defaults. To remove any configuration you must enter the default keyword with the command instead of the nokeyword. To disable an output chain-building characteristic, enter the no keyword.
The output of the showceftablecommand displays the current configuration and operational state of the Cisco Express Forwarding table.
Individual Overrides
This command is used for troubleshooting purposes only.
Note
Use this command only on the advice of field personnel from Cisco.
The use of the ceftableoutput-chainbuildcommand with either the indirection or inplace-modifykeyword overrides specific Cisco Express Forwarding table output chain-building behavior. Indirection characteristics are installed by default if the platform supports or permits their use.
The indirection keyword enables or disables the insertion of indirection objects for recursive or nonrecursive prefixes or for both recursive and nonrecursive prefixes. Inserting an indirection object into the forwarding chain allows the handling of any aggregate event that affects multiple prefixes by the modification of the indirection object. For example, if a number of recursive prefixes all share the same recursive nexthop, and the route to the recursive nexthop changes, a single update to an indirection object can restore forwarding for those recursive prefixes.
If you configure the ceftableoutput-chainbuildindirection command without a prefix type, recursive and nonrecursive prefixes are explicitly enabled. This command would override any preference configured with the existing ceftableoutput-chainbuildfavor command.
The inplace-modify keyword enables or disables the ability to modify certain objects in the forwarding chain by modifying the data that an object holds. The alternative is a complete replacement of the object and the relinking of all links to the object.
To return to system default settings for Cisco Express Forwarding table output chain building, use the default form of the command.
The output of the showceftablecommand displays the current configuration and operational state of the Cisco Express Forwarding table.
Examples
The following example shows how to configure the use of less memory for table output chain building:
Use this command if your priority is to save memory and your network does not require a faster convergence speed for table output chain building for forwarding of network traffic.
Related Commands
Command
Description
showceftable
Displays the configuration and operational state of the FIB.
showipcefswitchingstatistics
Displays switching statistics in the FIB.
showipv6cefswitchingstatistics
Displays switching statistics in the IPv6 FIB.
cef table rate-monitor-period
To set a time period over which to calculate the rate of route updates from the Routing Information Base (RIB) to the Cisco Express Forwarding Forwarding Information Base (FIB) tables, use the ceftablerate-monitor-periodcommand in global configuration mode. To return to the default time period, use the no form of this command.
ceftablerate-monitor-periodminutes
noceftablerate-monitor-periodminutes
Syntax Description
minutes
The time period, in minutes, over which to calculate the rate of route updates to Cisco Express Forwarding tables. The range is from 1 to 60. The default is 5.
Command Default
If the command is not configured, the sampling rate is every 5 minutes.
Command Modes
Global configuration (config)
Command History
Release
Modification
12.2(25)S
This command was introduced.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
Use this command to change the sampling rate period over which to monitor route updates from the RIB to the Cisco Express Forwarding IPv4 and IPv6 FIB tables. Changing the sampling period allows you to calculate the rate of route insertion into the FIB at any interval length from 1 minute to 60 minutes.
Examples
The following example shows how to set the time period to 1 minute over which to calculate the rate of route updates from the RIB to the IPv4 FIB and IPv6 FIB:
Router(config)# cef table rate-monitor-period 1
Related Commands
Command
Description
showceftable
Displays the configuration and operational state of the Cisco Express Forwarding FIB table.
clear adjacency
To clear the Cisco Express Forwarding adjacency table, use the clearadjacency command in privileged EXEC mode.
clearadjacency
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
11.2GS
This command was introduced to support the Cisco 12012 Internet router.
11.1CC
Support was added for multiple platforms.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB and implemented on the Cisco 10000 series routers.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
Using the clearadjacencycommand repopulates adjacencies from sources. Any remaining stale adjacencies (meaning those that fail to repopulate on request) are then purged. Layer 2 next hop information is reevaluated.
Clearing adjacencies cause the adjacency table to repopulate from the Layer 2 to Layer 3 mapping tables. To reevaluate the mappings, clear the source information by using a Cisco IOS command, such as the cleararp-cache command.
For Cisco 7500 Routers
On a distributed system, the adjacency tables that reside on line cards are always synchronized to the adjacency table that resides on the Route/Switch Processor (RSP). Refreshing the adjacencies also refreshes adjacencies on line cards and purges stale entries. (Entering the clearadjacency command on a line card has no effect.)
Examples
The following example clears the adjacency table:
Router# clear adjacency
Related Commands
Command
Description
cleararp-cache
Deletes all dynamic entries from the ARP cache.
debugadjacency
Enables the display of information about the adjacency database.
Displays information about the hardware Layer 3 switching adjacency node.
clear adjacency epoch
Note
Theclearadjacencyepochcommand is not available in Cisco IOS Releases 12.2(25)S, 12.2(28)SB, 12.2(33)SRA, 12.2(33)SXH, 12.4(20)T and later releases.
To begin a new epoch and increment the epoch number of the Cisco Express Forwarding adjacency table, use the clearadjacencyepoch command in privileged EXEC mode.
clearadjacencyepoch
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.2(8)T
This command was introduced.
12.2(25)S
This command was removed. It is not available in Cisco IOS Release 12.2(25)S and later Cisco IOS 12.2S releases.
12.2(28)SB
This command was removed. It is not available in Cisco IOS Release 12.2(28)SB and later Cisco IOS 12.2SB releases.
12.2(33)SRA
This command was removed. It is not available in Cisco IOS Release 12.2(33)SRAand later Cisco IOS 12.2SR releases.
12.2(33)SXH
This command was removed. It is not available in Cisco IOS Release 12.2(33)SXH and later Cisco IOS 12.2S releases.
12.4(20)T
This command was removed. It is not available in Cisco IOS Release 12.4(20)T and later Cisco IOS 12.4T releases.
Usage Guidelines
The clearadjacencyepochcommand increments the epoch and flushes entries with the old epoch. This command clears inconsistencies.
Use the clearadjacencyepochcommand when you want to rebuild the adjacency table. A new adjacency table might be required because the user wants to remove inconsistencies from the table.
Examples
The following example shows how to begin a new epoch and increments the epoch number of the adjacency table:
Router# clear adjacency epoch
clear cef interface
To clear the Cisco Express Forwarding per-interface traffic policy statistics for an interface, use the clearcefinterfacecommand in privileged EXEC mode.
(Optional) Line card slot number to clear. When you omit this argument, all line card slots are cleared.
adjacency
(Optional) Clears line card adjacency tables and rebuilds adjacency for the specified line card.
interface
(Optional) Clears line card interface information and recreates the interface information for the specified line card.
prefix
(Optional) Clears line card prefix tables and starts rebuilding the Forwarding Information Base (FIB) table.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
11.2GS
This command was introduced to support the Cisco 12012 Internet router.
11.1CC
Support was added for multiple platforms.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB and implemented on the Cisco 7000 series router. This command is not supported on the Cisco 10000 series router.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
Usage Guidelines
This command is available only on distributed platforms (such as the Cisco 7500 series) running distributed Cisco Express Forwarding.
Cisco Express Forwarding information on the line cards is cleared; however, Cisco Express Forwarding information on the Route Processor (RP) is not affected.
After you clear Cisco Express Forwarding information from line cards, the corresponding information from the RSP is propagated to the line cards. Interprocess communications (IPC) ensures that
Cisco Express Forwarding information on the Route Switch Processor (RSP) matches the Cisco Express Forwarding information on the line cards.
Because this command might require significant processing resources and can cause dropped traffic or system error messages about excessive CPU use, its use is recommended only as a last resort for debugging or mitigating serious problems.
Note
Cisco 10000 series routers do not support the clearceflinecard command.
Examples
The following example clears the Cisco Express Forwarding information from the line cards:
clear cef linecard
Related Commands
Command
Description
showceflinecard
Displays Cisco Express Forwarding-related interface information by line card.
clear cef load-balance statistics
To clear Cisco Express Forwarding (CEF) load balancing information, use the clearcefload-balancestatisticscommand in privileged EXEC mode.
clearcefload-balancestatistics
Syntax Description
This command has no arguments or keywords.
Command Default
Cisco Express Forwarding load balancing information is not cleared.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
15.0(1)M
This command was introduced in a release earlier than Cisco IOS Release 15.0(1)M.
12.2(33)SRC
This command was integrated into a release earlier than Cisco IOS Release 12.2(33)SRC.
12.2(33)SXI
This command was integrated into a release earlier than Cisco IOS Release 12.2(33)SXI.
Cisco IOS XE Release 2.1
This command was integrated into Cisco IOS XE Release 2.1.
Usage Guidelines
Cisco Express Forwarding load balancing is based on a combination of source and destination packet information; it allows you to optimize resources by distributing traffic over multiple paths for transferring data to a destination. You can use the clearcefload-balancestatistics command to clear Cisco Express Forwarding load balancing information. To select and configure the load balancing algorithm and to record the statistics, use theipcefload-sharingalgorithm command.
Examples
The following example shows how to clear CEF load balancing information:
Router# clear cef load-balance statistics
Related Commands
Command
Description
ipcefload-sharingalgorithm
Selects a Cisco Express Forwarding load-balancing algorithm.
showcef
Displays information about packets forwarded by Cisco Express Forwarding.
clear cef table
To clear the Cisco Express Forwarding tables, use the clearceftablecommand in privileged EXEC mode.
Clears the Cisco Express Forwarding tables for IPv4 addresses.
ipv6
Clears the Cisco Express Forwarding tables for IPv6 addresses.
Note
On the Cisco 10000 series routers IPv6 is supported on Cisco IOS
Release 12.2(28)SB and later releases.
vrf
(Optional) Specifies all VPN routing and forwarding (VRF) instance tables or a specific VRF table for an IPv4 or IPv6 address.
vrf-name
(Optional) Clears the specific VRF table for IPv4 or IPv6 addresses.
*
(Optional) Clears all the VRF tables for IPv4 or IPv6 addresses.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.2(25)S
This command was introduced.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
The clearceftable command clears the selected table or address family of tables (for IPv4 or IPv6) and updates (refreshes) them throughout the router (including the Route Processor and line cards). The command increments the table epoch, updates the tables, distributes the updated information to the line cards, and performs a distributed purge of any stale entries in the tables based on the noncurrent epoch number. This ensures that any inconsistencies that occurred over time are removed.
Because this command might require significant processing resources and can cause dropped traffic or system error messages about excessive CPU use, it’s use is recommended only as a last resort for debugging or mitigating serious problems.
Cisco Express Forwarding tables are also cleared automatically during bootup or online insertion and removal (OIR) of line cards.
Note
On the Cisco 10000 series routers, IPv6 is supported on Cisco IOS Release 12.2(28)SB or later releases.
Examples
The following example clears the Cisco Express Forwarding tables for the IPv6 address family:
Router# clear cef table ipv6 vrf *
The following example clears the Cisco Express Forwarding tables for a VRF table named vrf1 in the IPv4 address family:
Router# clear cef table ipv4 vrf vrf1
The following example clears the Cisco Express Forwarding tables for all VRF tables in the IPv4 address family. This example shows output with Cisco Express Forwarding table debugging enabled:
Displays Cisco Express Forwarding IP prefix inconsistencies.
clear ip cache
To delete entries in the routing table cache used to fast switch IP traffic, use the clearipcachecommand in privileged EXEC mode.
clearipcache
[ prefixmask ]
Syntax Description
prefixmask
(Optional) Deletes only the entries in the cache that match the prefix and mask combination.
Command Modes
Privileged EXEC (#)
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.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
Use this command to clear routes from the routing table cache. You can remove all entries in the routing cache or you can remove only those entries associated with a specified prefix and mask.
Note
IPv4 fast switching is not supported in Cisco IOS 12.4(20)T and later releases.
Examples
The following command shows how to delete the all of the entries in the routing table cache:
Router# clear ip cache
The following command show how to delete entries in the router table associated with the prefix and mask 192.168.32.0 255.255.255.0:
Router# clear ip cache 192.168.32.0 255.255.255.0
Related Commands
Command
Description
iproute-cache
Controls the use of high-speed switching caches for IP routing.
showipcache
Displays the routing table cache used to fast switch IP traffic.
clear ip cef epoch
Note
Theclearipcefepochcommand is not available in Cisco IOS Releases 12.2(25)S, 12.2(28)SB, 12.2(33)SRA, 12.2(33)SXH, 12.4(20)T, and later releases.
To begin a new epoch and increment the epoch number for one or all Cisco Express Forwarding tables, use the clearipcefepochcommand in privileged EXEC mode.
clearipcefepoch
[ all-vrfs | full | vrf [table] ]
Syntax Description
all-vrfs
(Optional) Begins a new epoch for all Forwarding Information Base (FIB) tables.
full
(Optional) Begins a new epoch for all tables, including adjacency tables.
vrf
(Optional) Begins a new epoch for the specified FIB table.
This command was integrated into Cisco IOS Release 12.2(14)S.
12.2(25)S
This command was removed. It is not available in Cisco IOS Release 12.2(25)S and later Cisco IOS 12.2S releases.
12.2(28)SB
This command was removed. It is not available in Cisco IOS Release 12.2(28)SB and later Cisco IOS 12.2SB releases.
12.2(33)SRA
This command was removed. It is not available in Cisco IOS Release 12.2(33)SRAand later Cisco IOS 12.2SR releases.
12.2(33)SXH
This command was removed. It is not available in Cisco IOS Release 12.2(33)SXH and later Cisco IOS 12.2SX releases.
12.4(20)T
This command was removed. It is not available in Cisco IOS Release 12.4(20)T and later Cisco IOS 12.4T releases.
Usage Guidelines
Use the clearipcefepochcommand when you want to rebuild a table. This command increments the epoch number and flushes entries with the old epoch number. This command clears any inconsistencies that might exist, so if everything in the system is working correctly, this command does not affect the Cisco Express Forwarding forwarding tables other than changing the current epoch values.
Examples
The following example shows the output before and after you clear the epoch table and increment the epoch number:
Router# show ip cef epoch
CEF epoch information:
Table: Default-table
Table epoch: 2 (43 entries at this epoch)
Adjacency table
Table epoch: 2 (5 entries at this epoch)
Router# clear ip cef epoch full
Router# show ip cef epoch
CEF epoch information:
Table: Default-table
Table epoch: 3 (43 entries at this epoch)
Adjacency table
Table epoch: 3 (5 entries at this epoch)
Related Commands
Command
Description
showcefstate
Displays the state of Cisco Express Forwarding.
showipcefepoch
Displays the table epochs of the adjacency table and of all FIB tables.
clear ip cef epoch full
To begin a new epoch and increment the epoch number for all Cisco Express Forwarding tables (including the adjacency table), use the clearipcefepochfull command in privileged EXEC mode.
clearipcefepochfull
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.2(14)SX
This command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
Use the clearipcefepochfull command when you want to rebuild a table. This command allows old and new table entries to be distinguished within the same data structure and allows you to retain the old Cisco Express Forwarding database table while constructing the new table.
These show commands display epoch information:
showipcefsummary--Displays the table epoch for a specific Forwarding Information Base (FIB) table.
showipcefdetail--Displays the epoch value for each entry of a specific FIB table.
showadjacencysummary--Displays the adjacency table epoch.
showadjacencydetail--Displays the epoch value for each entry of the adjacency table.
Examples
This example shows the output before and after you clear the epoch table and increment the epoch number:
Router# show ip cef epoch
CEF epoch information:
Table:Default-table
Table epoch:2 (164 entries at this epoch)
Adjacency table
Table epoch:1 (33 entries at this epoch)
Router# clear ip cef epoch full
Router# show ip cef epoch
CEF epoch information:
Table:Default-table
Table epoch:3 (164 entries at this epoch)
Adjacency table
Table epoch:2 (33 entries at this epoch)
Related Commands
Command
Description
show adjacency detail
Displays the information about the protocol detail and timer.
showadjacencysummary
Displays a summary of Cisco Express Forwarding adjacency information.
showipcefdetail
Displays detailed FIB entry information.
showipcefsummary
Displays a summary of the FIB.
clear ip cef event-log
Note
Effective with Cisco IOS 12.2(25)S, the clearipcefevent-logcommand is replaced by the monitorevent-tracecefipv4clear command. See the monitorevent-trace (EXEC) command for more information.
To clear the Cisco Express Forwarding event-log buffer, use the clearipcefevent-log command in privileged EXEC mode.
clearipcefevent-log
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.0(15)S
This command was introduced.
12.2(2)T
This command was integrated into Cisco IOS Release 12.2(2)T.
12.2(25)S
This command was replaced by the monitorevent-tracecefipv4clear command.
12.2(33)SRA
This command was replaced by the monitorevent-tracecefipv4clear command.
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.
12.4(20)T
This command was replaced by the monitorevent-tracecefipv4clear command.
Usage Guidelines
This command clears the entire Cisco Express Forwarding table event log that holds Forwarding Information Base (FIB) and adjacency events.
Examples
The following example shows how to clear the Cisco Express Forwarding event-log buffer:
Router# clear ip cef event-log
Related Commands
Command
Description
ceftableconsistency-check
Enables Cisco Express Forwarding table consistency checker types and parameters.
Displays all recorded Cisco Express Forwarding FIB and adjacency events.
clear ip cef inconsistency
To clear the Cisco Express Forwarding inconsistency checker statistics and records found by the Cisco Express Forwarding consistency checkers, use the clearipcefinconsistency command in privileged EXEC mode.
clearipcefinconsistency
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.0(15)S
This command was introduced.
12.2(2)T
This command was integrated into Cisco IOS Release 12.2(2)T.
12.2(25)S
This command was integrated into Cisco IOS Release 12.2(25)S.
12.2(14)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to the 12.2(17d)SXB release.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB and implemented on the Cisco 10000 series routers.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SR.
12.2(33)SXH
This command was integrated into Cisco IOS Release 12.2(33)SXH.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
This command clears the Cisco Express Forwarding inconsistency checker statistics and records that accumulate when the ceftableconsistency-check command is enabled.
Examples
The following example shows how to clear all Cisco Express Forwarding inconsistency checker statistics and records:
Router# clear ip cef inconsistency
Related Commands
Command
Description
ceftableconsistency-check
Enables Cisco Express Forwarding table consistency checker types and parameters.
showipcefinconsistency
Displays Cisco Express Forwarding IP prefix inconsistencies.
clear ip cef prefix-statistics
To clear Cisco Express Forwarding counters by resetting the packet and byte count to zero (0), use the clearipcefprefix-statistics command in privileged EXEC mode.
clearipcefnetwork [mask] prefix-statistics
Syntax Description
network
Forwarding Information Base (FIB) entry specified by network.
mask
(Optional) FIB entry specified by network and mask.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
11.2GS
This command was introduced to support the Cisco 12012 Internet router.
11.1CC
Support for multiple platform was added.
12.2(25)S
The * (asterisk) keyword was removed.
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.
12.4(20)T
This command was integrated into Cisco IOS Release 12.4(20)T.
Usage Guidelines
When the clear statistics flag is set, statistics are cleared as the FIB table is scanned. The time period is up to 60 seconds for all statistics to clear. However, clearing a specific prefix is completed immediately.
Examples
The following example shows how to reset the packet and byte counts to zero for Cisco Express Forwarding entries on the 172.17.10.10 network:
Router# clear ip cef 172.17.10.10 prefix-statistics
To clear multicast distributed switching (MDS) information from the router, use the clearipmdscommand in privileged EXEC mode.
clearipmds
{ all | [ vrfvrf-name ]
forwarding }
Syntax Description
all
Clear all IP MDS information.
vrf
(Optional) A Virtual Private Network (VPN) routing and forwarding (VRF) instance.
vrf-name
(Optional) Name assigned to the VRF.
forwarding
Clears all linecard routes from a Multicast Forwarding Information Base (MFIB) table and resynchronizes it with the Route Processor (RP).
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
11.2(11)GS
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
Cisco 12000 Series Internet Router
On a Cisco 12000 series Internet router the clearipmds command must be run in privileged EXEC mode on a linecard.
Examples
The following example clears all line card routes in an MFIB table on a Cisco 12000 series Internet router:
Router# attach 1
LC-Slot1> enable
LC-Slot1# clear ip mds forwarding
The following example clears all line card routes in an MFIB table on a Cisco 7500 series router:
Router# clear ip mds forwarding
Related Commands
Command
Description
showipmdsinterface
Displays the MFIB table and forwarding information for MDS on a line card.
showipmdsstats
Display switching statistics or line card statistics for MDS.
showipmdssummary
Displays a summary of the MFIB table for MDS.
showipmdsforwarding
Displays MDS information for all the interfaces on the line card.
clear ip mds forwarding
The forwardingkeyword for the clearipmdscommand is no longer documented as a separate command.
The information for using the forwardingkeyword for the clearipmdscommand has been incorporated into the clearipmdscommand documentation. See the clearipmds command documentation for more information.
clear ip mds linecard
To reset multicast distributed switching (MDS) line card information on the router, use the clearipmdslinecard command in privileged EXEC mode.
clearipmdslinecard
{ linecard-slot-number | * }
Syntax Description
linecard-slot-number
Slot number containing the line card to be reset.
*
Indicates that the reset should be executed on all line cards.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.0(19.3)S
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
When the * keyword is specified instead of the linecard-slot-number argument, all MDS information on all line cards is cleared and reset.
Examples
The following example clears and resets all MDS line card information on the router:
Router# clear ip mds linecard *
Related Commands
Command
Description
showipmds
Clears MDS information from the router.
showipmdsinterface
Displays the MFIB table and forwarding information for MDS on a line card.
showipmdsstats
Display switching statistics or line card statistics for MDS.
showipmdssummary
Displays a summary of the MFIB table for MDS.
showipmdsforwarding
Displays MDS information for all the interfaces on the line card.
clear ip traffic
To clear the global or system-wide IP traffic statistics for one or more interfaces, use the cleariptraffic command in privileged EXEC mode.
cleariptraffic
[ interfacetypenumber ]
Syntax Description
interfacetypenumber
(Optional) Clears the global or system-wide IP traffic statistics for a specific interface. If the interface keyword is used, the type and number arguments are required.
Command Default
Using the cleariptraffic command with no keywords or arguments clears the global or system-wide IP traffic statistics for all interfaces.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.4(2)T
This command was introduced.
12.2(31)SB2
This command was integrated into Cisco IOS Release 12.2(31)SB2.
Cisco IOS XE Release 2.1
This command was integrated into Cisco IOS XE Release 2.1.
Cisco IOS XE Release 3.1S
This command was modified to include the optional interface keyword and associated type and number arguments. These modifications were made to provide support for the IPv4 MIBs as described in RFC 4293, Management Information Base for the Internet Protocol (IP)
.
15.1(4)M
This command was modified. The optional interface keyword and associated type and number arguments were added. These modifications were made to provide support for the IPv4 MIBs as described in RFC 4293, Management Information Base for the Internet Protocol (IP)
.
Usage Guidelines
Using the cleariptrafficcommand with the optional interface keyword clears the ipIfStatsTable counters displayed for the specified interface and also clears the counters displayed by the showiptrafficinterface command.
Examples
The following example shows how to clear the global or system-wide IP traffic statistics on all interfaces:
Router# clear ip traffic
The following example shows how to clear the IP traffic statistics on Ethernet interface 0/0:
Router# clear ip traffic interface ethernet 0/0
The following is sample output from the showiptraffic command for Ethernet interface 0/0 after clearing the traffic using the cleariptraffic command:
Router# show ip traffic
Ethernet0/0 IP-IF statistics :
Rcvd: 0 total, 0 total_bytes
0 format errors, 0 hop count exceeded
0 bad header, 0 no route
0 bad destination, 0 not a router
0 no protocol, 0 truncated
0 forwarded
0 fragments, 0 total reassembled
0 reassembly timeouts, 0 reassembly failures
0 discards, 0 delivers
Sent: 0 total, 0 total_bytes 0 discards
0 generated, 0 forwarded
0 fragmented into, 0 fragments, 0 failed
Mcast: 0 received, 0 received bytes
0 sent, 0 sent bytes
Bcast: 0 received, 0 sent
Related Commands
Command
Description
showiptraffic
Displays the global or system-wide IP traffic statistics for one or more interfaces.
clear mls cef ip accounting per-prefix
To clear information about the IP per-prefix accounting statistics, use the clearmlscefipaccountingper-prefixcommand in privileged EXEC mode.
clearmlscefipaccountingper-prefix
{ all | prefixmask [instance] }
Syntax Description
all
Clears all per-prefix accounting statistics information.
prefix
Entry prefix in the format A.B.C.D.
mask
Entry prefix mask.
instance
(Optional) VPN routing and forwarding instance name.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.2(17a)SX
Support for this command was introduced on the Supervisor Engine 720.
12.2(17d)SXB
Support for this command on the Supervisor Engine 2 was extended to Release 12.2(17d)SXB.
12.2(33)SRA
This command was integrated into Cisco IOS Release 12.2(33)SRA.
Examples
This example shows how to clear all information about the per-prefix accounting statistics:
Router#
clear mls cef ip accounting per-prefix all
clear pxf
To clear Parallel eXpress Forwarding (PXF) counters and statistics, use the clearpxfcommand in privileged EXEC mode.
(Optional) Clears the direct memory access (DMA) PXF counters.
interfaceinterface
(Optional) Clears the PXF counters on the specified interface.
statistics
(Optional) Type of PXF statistics to clear. The options are:
context--Current and historical loads on the PXF.
diversion--Traffic diverted from the PXF.
drop--Dropped packets and bytes.
ip-- IP and ICMP statistics.
ipv6--IPv6 statistics.
xcm counters
Clears the PXF Error Code Correction (ECC) counters.
Command Modes
Privileged EXEC (#)
Command History
Release
Modification
12.0(22)S
This command was introduced on the Cisco 10000 series router.
12.2(1)XF1
This command was introduced on the Cisco uBR10012 router.
12.2(4)XF1
The xcmcounters option was introduced to support the Performance Routing Engine (PRE1) module on the Cisco uBR10012 router.
12.3(7)XI1
This command was integrated into Cisco IOS Release 12.3(7)XI1.
12.3BC
This command was integrated into Cisco IOS Release 12.3BC. The context and ipv6 keyword options are not supported.
12.2(31)SB
This command was integrated into Cisco IOS Release 12.2(31)SB.
12.2(33)SCA
This command was integrated into Cisco IOS Release 12.2(33)SCA. The ipv6 keyword option is not supported.
Usage Guidelines
If no interface is specified, the command clears PXF counters on all interfaces. The clearpxfcommand clears counters associated with the showpxfdma, showpxfinterface, showpxfstatistics, and showpxfxcm commands.
Cisco uBR10012 Universal Broadband Router
Not all keyword options are supported in the Cisco IOS software for the Cisco uBR10012 universal broadband router. See the command history table for the unsupported keyword options by release.
The clearpxfxcmcounterscommand is supported only on the PRE1 and later processors for the Cisco uBR10012 router. This command is not supported on the PRE processor.
Examples
The following example clears PXF statistics for serial interface 1/0/0:
Router# clear pxf interface serial 1/0/0
The following example clears PXF statistics on all interfaces:
Router# clear pxf interface
Related Commands
Command
Description
showpxfcpustatistics
Displays PXF CPU statistics.
showpxfdma
Displays the current state of DMA buffers, error counters, and registers on the PXF engine.
showpxfinterface
Displays a summary of the statistics accumulated by column 0 of the PXF for an interface.