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Cisco IOS IP Routing Protocols Command Reference
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Introduction
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BGP Commands: A through B
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BGP Commands: C through I
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BGP Commands: M through neighbor soo
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BGP Commands: neighbor timers through show bgp nsap summary
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BGP Commands: show ip bgp through T
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EIGRP Commands: A through I
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EIGRP Commands: M through V
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Integrated IS-IS Commands: A through I
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Integrated IS-IS Commands: L through V
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On-Demand Routing Commands
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OSPF Commands: A through ip ospf demand-circuit
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OSPF Commands: ip ospf flood-reduction through R
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OSPF Commands: show ip ospf through T
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IP Routing Protocol-Independent Commands: A through R
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IP Routing Protocol-Independent Commands: S through T
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RIP Commands
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Table Of Contents
clear bgp nsap flap-statistics
default-information originate (BGP)
ip prefix-list sequence-number
clear bgp nsap
To clear and then reset Connectionless Network Service (CLNS) network service access point (NSAP) Border Gateway Protocol (BGP) sessions, use the clear bgp nsap command in privileged EXEC mode.
clear bgp nsap {* | as-number | ip-address} [soft] [in | out]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.2(8)T
This command was introduced.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
Usage Guidelines
The clear bgp nsap command is similar to the clear ip bgp command, except that it is NSAP address family-specific.
Use of the clear bgp nsap command allows a reset of the neighbor sessions with varying degrees of severity, depending on the specified keywords and arguments.
Use the * keyword to reset all neighbor sessions. The software will clear and then reset the neighbor connections. Use this form of the command in the following situations:
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BGP timer specification change
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Use the soft out keywords to clear and reset only the outbound neighbor connections. Inbound neighbor sessions will not be reset. Use this form of the command in the following situations:
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Use the in keyword to clear only the inbound neighbor connections. Outbound neighbor sessions will not be reset. Use this form of the command in the following situations:
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Examples
In the following example, the inbound session with the neighbor 172.20.16.6 is cleared without the outbound session being reset:
Router# clear bgp nsap 172.20.16.6 inIn the following example, a soft clear is applied to outbound sessions with the neighbors in autonomous system 65000 without the inbound session being reset:
Router# clear bgp nsap 65000 soft outRelated Commands
show bgp nsap
Displays entries in the BGP routing table for the NSAP address family.
clear bgp nsap dampening
To clear Border Gateway Protocol (BGP) route dampening information for the network service access point (NSAP) address family and unsuppress the suppressed routes, use the clear bgp nsap dampening command in privileged EXEC mode.
clear bgp nsap dampening [nsap-prefix]
Syntax Description
nsap-prefix
(Optional) NSAP prefix about which to clear dampening information. This argument can be up to 20 octets long.
Command Default
When the nsap-prefix argument is not specified, the clear bgp nsap dampening command clears route dampening information for the entire BGP routing table for the NSAP address family.
Command Modes
Privileged EXEC
Command History
12.2(8)T
This command was introduced.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
Usage Guidelines
The clear bgp nsap dampening command is similar to the clear ip bgp dampening command, except that it is specific to the NSAP address family.
Examples
In the following example, route dampening information is cleared for the route to NSAP prefix 49.6001 and locally suppressed routes are unsuppressed:
Router# clear bgp nsap dampening 49.6001Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
show bgp nsap dampened-paths
Displays BGP dampened routes for the NSAP address family.
clear bgp nsap external
To clear all external BGP (eBGP) peers for the network service access point (NSAP) address family, use the clear bgp nsap external command in privileged EXEC mode.
clear bgp nsap external [soft] [in | out]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.2(8)T
This command was introduced.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
Usage Guidelines
The clear bgp nsap external command is similar to the clear ip bgp external command, except that it is specific to the NSAP address family.
Examples
In the following example, the inbound sessions with external BGP peers are cleared without the outbound sessions being reset:
Router# clear bgp nsap external soft inRelated Commands
clear bgp nsap flap-statistics
To clear Border Gateway Protocol (BGP) flap statistics for the network service access point (NSAP) address family, use the clear bgp nsap flap-statistics command in privileged EXEC mode.
clear bgp nsap flap-statistics [nsap-prefix] [regexp regexp | filter-list access-list-number]
Syntax Description
Command Default
No statistics are cleared.
If no arguments or keywords are specified, the software clears flap statistics for all routes.
Command Modes
Privileged EXEC
Command History
12.2(8)T
This command was introduced.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
Usage Guidelines
The clear bgp nsap flap-statistics command is similar to the clear ip bgp flap-statistics command, except that it is specific to the NSAP address family.
The flap statistics for a route are also cleared when an NSAP BGP peer is reset. Although the reset withdraws the route, no penalty is applied in this instance even though route flap dampening is enabled.
Examples
In the following example, all of the flap statistics for paths that pass access list 3 are cleared:
Router# clear bgp nsap flap-statistics filter-list 3Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
show bgp nsap flap-statistics
Displays BGP flap statistics for the NSAP address family.
clear bgp nsap peer-group
To clear the Border Gateway Protocol (BGP) TCP connections to all members of a BGP peer group for the network service access point (NSAP) address family, use the clear bgp nsap peer-group command in privileged EXEC mode.
clear bgp nsap peer-group peer-group-name
Syntax Description
Command Default
No BGP TCP connections are cleared.
Command Modes
Privileged EXEC
Command History
12.2(8)T
This command was introduced.
12.2(33)SRB
This command was integrated into Cisco IOS Release 12.2(33)SRB.
Usage Guidelines
The clear bgp nsap peer-group command is similar to the clear ip bgp peer-group command, except that it is specific to the NSAP address family.
Examples
In the following example, the BGP TCP connections are cleared for all members of the NSAP BGP peer group named internal:
Router# clear bgp nsap peer-group internalRelated Commands
neighbor peer-group (assigning members)
Configures a BGP neighbor to be a member of a peer group.
clear ip bgp
To reset Border Gateway Protocol (BGP) connections using hard or soft reconfiguration, use the clear ip bgp command in privileged EXEC mode.
clear ip bgp {* | all | autonomous-system-number | neighbor-address} [in [prefix-filter]] [out]} [soft [in [prefix-filter] | out]]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp command can be used to initiate a hard reset or soft reconfiguration. A hard reset tears down and rebuilds the specified peering sessions and rebuilds the BGP routing tables. A soft reconfiguration uses stored prefix information to reconfigure and activate BGP routing tables without tearing down existing peering sessions. Soft reconfiguration uses stored update information, at the cost of additional memory for storing the updates, to allow you to apply new BGP policy without disrupting the network. Soft reconfiguration can be configured for inbound or outbound sessions.
Note
Generating Updates from Stored Information
To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use this command whenever any of the following changes occur:
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Dynamic Inbound Soft Reset
The route refresh capability, as defined in RFC 2918, allows the local router to reset inbound routing tables dynamically by exchanging route refresh requests to supporting peers. The route refresh capability does not store update information locally for non-disruptive policy changes. It instead relies on dynamic exchange with supporting peers. Route refresh is advertised through BGP capability negotiation. All BGP routers must support the route refresh capability.
To determine if a BGP router supports this capability, use the show ip bgp neighbors command. The following message is displayed in the output when the router supports the route refresh capability:
Received route refresh capability from peer.If all BGP routers support the route refresh capability, use the clear ip bgp command with the in keyword. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.
Note
Examples
In the following example, a soft reconfiguration is initiated for the inbound session with the neighbor 10.100.0.1, and the outbound session is unaffected:
Router# clear ip bgp 10.100.0.1 soft inIn the following example, the route refresh capability is enabled on the BGP neighbor routers and a soft reconfiguration is initiated for the inbound session with the neighbor 172.16.10.2, and the outbound session is unaffected:
Router# clear ip bgp 172.16.10.2 inIn the following example, a hard reset is initiated for sessions with all routers in the autonomous system numbered 35700:
Router# clear ip bgp 35700Related Commands
clear ip bgp dampening
To clear BGP route dampening information and to unsuppress suppressed routes, use the clear ip bgp dampening command in privileged EXEC mode.
Syntax Without Address Family Syntax
clear ip bgp dampening [network-address] [ipv4-mask]
Syntax With Address Family Syntax
clear ip bgp [ipv4 {multicast | unicast} | vpnv4 unicast] dampening [network-address] [ipv4-mask]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp dampening is used to clear stored route dampening information. If no keywords or arguments are entered, route dampening information for the entire routing table is cleared.
Examples
The following example clears route dampening information for VPNv4 address family prefixes from network 192.168.10.0/24 and unsuppress suppressed routes.
Router# clear ip bgp vpnv4 unicast dampening 192.168.10.0 255.255.255.0Related Commands
clear ip bgp external
To reset external Border Gateway Protocol (eBGP) peering sessions using hard or soft reconfiguration, use the clear ip bgp external command in privileged EXEC mode.
Syntax Without Address Family Syntax
clear ip bgp external [in [prefix-filter]] [out] [soft [in [prefix-filter] | out]]
Syntax With Address Family Syntax
clear ip bgp external [all | ipv4 {multicast | mdt | unicast} | ipv6 {multicast | unicast} | vpnv4 unicast | vpnv6 unicast] [in [prefix-filter]] [out] [soft [in [prefix-filter] | out]]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp external command can be used to initiate a hard reset or soft reconfiguration of eBGP neighbor sessions. A hard reset tears down and rebuilds the specified peering sessions and rebuilds the BGP routing tables. A soft reconfiguration uses stored prefix information to reconfigure and activate BGP routing tables without tearing down existing peering sessions. Soft reconfiguration uses stored update information, at the cost of additional memory for storing the updates, to allow you to apply new BGP policy without disrupting the network. Soft reconfiguration can be configured for inbound or outbound sessions.
Generating Updates from Stored Information
To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use this command whenever any of the following changes occur:
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Dynamic Inbound Soft Reset
The route refresh capability, as defined in RFC 2918, allows the local router to reset inbound routing tables dynamically by exchanging route refresh requests to supporting peers. The route refresh capability does not store update information locally for non-disruptive policy changes. It instead relies on dynamic exchange with supporting peers. Route refresh is advertised through BGP capability negotiation. All BGP routers must support the route refresh capability.
To determine if a BGP router supports this capability, use the show ip bgp neighbors command. The following message is displayed in the output when the router supports the route refresh capability:
Received route refresh capability from peer.If all BGP routers support the route refresh capability, use the clear ip bgp command with the in keyword. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.
Note
Examples
In the following example, a soft reconfiguration is configured for all inbound eBGP peering sessions:
Router# clear ip bgp external soft inIn the following example, all outbound address family IPv4 multicast eBGP peering sessions are cleared:
Router# clear ip bgp external ipv4 multicast outRelated Commands
clear ip bgp flap-statistics
To clear BGP route dampening flap statistics, use the clear ip bgp flap-statistics command in privileged EXEC mode.
Syntax Without Address Family Syntax
clear ip bgp flap-statistics [neighbor-address [ipv4-mask]] [regexp regexp | filter-list extcom-number]
Syntax With Address Family Syntax
clear ip bgp [neighbor-address] [all | ipv4 {multicast | mdt | unicast} | ipv6 {multicast | unicast} | vpnv4 unicast | vpnv6 unicast] flap-statistics
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp flap-statistics command is used to clear the accumulated penalty for routes that are received on a router that has BGP dampening enabled. If no arguments or keywords are specified, flap statistics are cleared for all routes. Flap statistics are also cleared when the peer is stable for the half-life time period.
Examples
In the following example, all of the flap statistics are cleared for paths that pass filter list 3:
Router# clear ip bgp flap-statistics filter-list 3In the following example, all of the flap statistics are cleared for the paths to the BGP neighbor at 10.2.1.3:
Router# clear ip bgp 10.2.1.3 flap-statisticsIn the following example, all of the flap statistics are cleared for the paths to the BGP neighbor at 10.2.1.3 under IPv4 multicast address family:
Router# clear ip bgp 10.2.1.3 ipv4 multicast flap-statisticsRelated Commands
clear ip bgp in prefix-filter
The in and prefix-filter keywords for the clear ip bgp command are no longer documented as a separate command.
The information for using the in and prefix-filter keywords with the clear ip bgp command has been incorporated into all the appropriate clear ip bgp command documentation. Due to the complexity of some of the keywords available for the clear ip bgp command, some of the keywords are documented as separate commands. All of the complex keywords that are documented separately start with clear ip bgp. For example, for information on resetting BGP connections using hard or soft reconfiguration for all BGP neighbors in IPv4 address family sessions, refer to the clear ip bgp ipv4 command.
clear ip bgp ipv4
To reset Border Gateway Protocol (BGP) connections using hard or soft reconfiguration for IPv4 address family sessions, use the clear ip bgp ipv4 command in privileged EXEC mode.
clear ip bgp ipv4 {multicast | mdt | unicast} autonomous-system-number [in [prefix-filter]] [out] [soft [in [prefix-filter] | out]]
Syntax Description
Command Modes
Privileged EXEC (#)
Command History
Usage Guidelines
The clear ip bgp ipv4 command can be used to initiate a hard reset or soft reconfiguration. A hard reset tears down and rebuilds the specified peering sessions and rebuilds the BGP routing tables. A soft reconfiguration uses stored prefix information to reconfigure and activate BGP routing tables without tearing down existing peering sessions. Soft reconfiguration uses stored update information, at the cost of additional memory for storing the updates, to allow you to apply new BGP policy without disrupting the network. Soft reconfiguration can be configured for inbound or outbound sessions.
Generating Updates from Stored Information
To generate new inbound updates from stored update information (rather than dynamically generating inbound updates) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use this command whenever any of the following changes occur:
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Dynamic Inbound Soft Reset
The route refresh capability, as defined in RFC 2918, allows the local router to reset inbound routing tables dynamically by exchanging route refresh requests to supporting peers. The route refresh capability does not store update information locally for nondisruptive policy changes. It instead relies on dynamic exchange with supporting peers. Route refresh is advertised through BGP capability negotiation. All BGP routers must support the route refresh capability.
To determine if a BGP router supports this capability, use the show ip bgp neighbors command. The following message is displayed in the output when the router supports the route refresh capability:
Received route refresh capability from peer.If all BGP routers support the route refresh capability, use the clear ip bgp ipv4 command with the in keyword. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.
Note
Examples
In the following example, a soft reconfiguration is initiated for the inbound sessions for BGP neighbors in IPv4 unicast address family sessions in autonomous system 65400, and the outbound session is unaffected:
Router# clear ip bgp ipv4 unicast 65400 soft inIn the following example, the route refresh capability is enabled on the IPv4 multicast address family BGP neighbors in autonomous system 65000, a soft reconfiguration is initiated for all inbound sessions with the IPv4 multicast address family neighbors, and the outbound session is unaffected:
Router# clear ip bgp ipv4 multicast 65000 inIn the following example, a hard reset is initiated for all BGP neighbor in IPv4 MDT address family sessions in the autonomous system numbered 65700:
Router# clear ip bgp ipv4 mdt 65700Related Commands
clear ip bgp ipv6
To reset Border Gateway Protocol (BGP) connections using hard or soft reconfiguration for IPv6 address family sessions, use the clear ip bgp ipv6 command in privileged EXEC mode.
clear ip bgp ipv6 {multicast | unicast} autonomous-system-number [in [prefix-filter]] [out]
[soft [in [prefix-filter] | out]]Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp ipv6 command can be used to initiate a hard reset or soft reconfiguration of IPv6 address family sessions. A hard reset tears down and rebuilds the specified peering sessions and rebuilds the BGP routing tables. A soft reconfiguration uses stored prefix information to reconfigure and activate BGP routing tables without tearing down existing peering sessions. Soft reconfiguration uses stored update information, at the cost of additional memory for storing the updates, to allow you to apply new BGP policy without disrupting the network. Soft reconfiguration can be configured for inbound or outbound sessions.
Generating Updates from Stored Information
To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use this command whenever any of the following changes occur:
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Dynamic Inbound Soft Reset
The route refresh capability, as defined in RFC 2918, allows the local router to reset inbound routing tables dynamically by exchanging route refresh requests to supporting peers. The route refresh capability does not store update information locally for non-disruptive policy changes. It instead relies on dynamic exchange with supporting peers. Route refresh is advertised through BGP capability negotiation. All BGP routers must support the route refresh capability.
To determine if a BGP router supports this capability, use the show ip bgp neighbors command. The following message is displayed in the output when the router supports the route refresh capability:
Received route refresh capability from peer.If all BGP routers support the route refresh capability, use the clear ip bgp ipv6 command with the in keyword. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.
Note
Examples
In the following example, a soft reconfiguration is initiated for the inbound sessions for BGP neighbors in IPv6 unicast address family sessions, and the outbound session is unaffected:
Router# clear ip bgp ipv6 unicast soft inIn the following example, the route refresh capability is enabled on the IPv6 multicast address family BGP neighbors and a soft reconfiguration is initiated for all inbound session with the IPv6 multicast address family neighbors, and the outbound session is unaffected:
Router# clear ip bgp ipv6 multicast inIn the following example, a hard reset is initiated for neighbor sessions with all IPv6 unicast address family routers in the autonomous system numbered 35700:
Router# clear ip bgp ipv6 unicast 35700Related Commands
neighbor soft-reconfiguration
Configures the Cisco IOS software to start storing updates.
show ip bgp neighbors
Displays information about BGP and TCP connections to neighbors.
clear ip bgp l2vpn
To reset Border Gateway Protocol (BGP) neighbor session information for Layer 2 Virtual Private Network (L2VPN) address family, use the clear ip bgp l2vpn command in privileged EXEC mode.
clear ip bgp l2vpn vpls {autonomous-system-number | peer-group peer-group-name | update-group [number | ip-address]} [in [prefix-filter] | out | soft [in [prefix-filter] | out]]
Syntax Description
Command Default
If no arguments or keywords are specified, all BGP L2VPN VPLS neighbor session information is cleared.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear ip bgp l2vpn command clears BGP session information for the L2VPN address family and VPLS SAFI. This command can be used to initiate a hard reset or soft reconfiguration. A hard reset tears down and rebuilds the specified peering sessions and rebuilds the BGP routing tables. A soft reconfiguration uses stored prefix information to reconfigure and activate BGP routing tables without tearing down existing peering sessions. Soft reconfiguration uses stored update information, at the cost of additional memory for storing the updates, to allow you to apply new BGP policy without disrupting the network. Soft reconfiguration can be configured for inbound or outbound sessions.
Generating Updates from Stored Information
To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use the clear ip bgp l2vpn command whenever any of the following changes occur:
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