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 no form of this command.

neighbor peer-group-name peer-group

no neighbor peer-group-name peer-group

Syntax Description

Defaults

There is no BGP peer group.

Command Modes

Address family configuration

Router configuration

Command History

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.

Note Peer 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.

Peer group members will always inherit the following configuration options: remote-as (if configured), version, update-source, out-route-map, out-filter-list, out-dist-list, minimum-advertisement-interval, and next-hop-self. All the peer group members will inherit changes made to the peer group.

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:

•internal Border Gateway Protocol (iBGP) peer group

•eBGP peer group

•Multiprotocol BGP peer group

iBGP 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 171.69.232.55, 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 171.69.232.53 peer-group internal

 neighbor 171.69.232.54 peer-group internal

 neighbor 171.69.232.55 peer-group internal

 neighbor 171.69.232.55 filter-list 3 in

eBGP Peer Group

The 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 171.69.232.110, 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 171.69.232.90 remote-as 200

 neighbor 171.69.232.90 peer-group external-peers

 neighbor 171.69.232.100 remote-as 300

 neighbor 171.69.232.100 peer-group external-peers

 neighbor 171.69.232.110 remote-as 400

 neighbor 171.69.232.110 peer-group external-peers

 neighbor 171.69.232.110 filter-list 400 in

Multiprotocol BGP Peer Group

In 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 activate

Related Commands

neighbor prefix-list

To distribute BGP neighbor information as specified in a prefix list, use the neighbor prefix-list command in address family or router configuration mode. To remove an entry, use the no form of this command.

neighbor {ip-address | peer-group-name} prefix-list prefix-list-name {in | out}

no neighbor {ip-address | peer-group-name} prefix-list prefix-list-name {in |out}

Syntax Description

Defaults

No BGP neighbor is specified.

Command Modes

Address family configuration

Router configuration

Command History

Usage Guidelines

Using prefix lists is one of two ways to filter BGP advertisements. The other way is to use AS-path filters, as with the ip as-path access-list global configuration command and the neighbor filter-list command, and access or prefix lists, as with the neighbor distribute-list command.

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.

Note Do 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 prefix-list or neighbor distribute-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 to neighbor 120.23.4.1:

router bgp 109

 network 10.108.0.0

 neighbor 120.23.4.1 prefix-list abc in

The following address family configuration mode example applies the prefix list named abc to incoming advertisements to neighbor 120.23.4.1:

router bgp 109

address-family ipv4 unicast

 network 10.108.0.0

 neighbor 120.23.4.1 prefix-list abc in

The following example applies the prefix list named CustomerA to outgoing advertisements to neighbor 120.23.4.1:

router bgp 109

 network 10.108.0.0

 neighbor 120.23.4.1 prefix-list CustomerA out

Related Commands

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 | peer-group-name} remote-as as-number

no neighbor {ip-address | peer-group-name} remote-as as-number

Syntax Description

Defaults

There are no BGP or multiprotocol BGP neighbor peers.

Command Modes

Router configuration

Command History

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 using the neighbor activate command in address family configuration mode.

Examples

The following example specifies that a router at the address 10.108.1.2 is a neighbor in autonomous system number 109:

router bgp 110

 network 10.108.0.0

 neighbor 10.108.1.2 remote-as 109

The following example assigns a BGP router to autonomous system 109, 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 192.31.7.0 with the neighbor routers. The first router listed is in the same Class B network address space, but in a different autonomous system; the second neighbor remote-as command illustrates specification of an internal 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.

router bgp 109

 network 10.108.0.0

 network 192.31.7.0

 neighbor 10.108.200.1 remote-as 167

 neighbor 10.108.234.2 remote-as 109

 neighbor 150.136.64.19 remote-as 99

The following example configures neighbor 10.108.1.1 in autonomous system 1 to exchange only multicast routes:

router bgp 109

neighbor 10.108.1.1 remote-as 1

neighbor 131.108 1.2 remote-as 1

neighbor 172.16.2.2 remote-as 2

address-family ipv4 multicast

  neighbor 10.108.1.1 activate

  neighbor 131.108 1.2 activate

  neighbor 172.16.2.2 activate

The following example configures neighbor 10.108.1.1 in autonomous system 1 to exchange only unicast routes:

router bgp 109

neighbor 10.108.1.1 remote-as 1

neighbor 131.108 1.2 remote-as 1

neighbor 172.16.2.2 remote-as 2

Related Commands

neighbor remove-private-as

To remove private autonomous system numbers from t in outbound routing updates, use the neighbor remove-private-as command in router configuration mode. To disable this function, use the no form of this command.

neighbor {ip-address | peer-group-name} remove-private-as

no neighbor {ip-address | peer-group-name} remove-private-as

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Usage Guidelines

This command is available for external BGP (eBGP) neighbors only.

When an update is passed to the external neighbor, if the autonomous system path includes private autonomous system numbers, the software will drop the private autonomous system numbers.

If the autonomous system path includes both private and public autonomous system numbers, the software considers this to be a configuration error and does not remove the private autonomous system numbers.

If the autonomous system path contains the autonomous system number of the eBGP neighbor, the private autonomous system numbers will not be removed.

If this command is used with confederation, it will work as long as the private autonomous system numbers follow the confederation portion of the autonomous path.

The private autonomous system values are from 64512 to 65535.

Examples

The following example shows a configuration that will remove the private autonomous system number from the updates sent to 172.16.2.33. The result is that the autonomous system path for the paths advertised by 10.108.1.1 through autonomous system 100 will just contain "100" (as seen by autonomous system 2051).

router bgp 100 

 neighbor 10.108.1.1 description peer with private-as 

 neighbor 10.108.1.1 remote-as 65001 

 neighbor 172.16.2.33 description eBGP peer 

 neighbor 172.16.2.33 remote-as 2051 

 neighbor 172.16.2.33 remove-private-as 

router-in-AS100# show ip bgp 10.0.0.0 

BGP routing table entry for 10.0.0.0/8, version 15 

Paths: (1 available, best #1) 

  Advertised to non peer-group peers: 

    172.16.2.33 

  65001 

    10.108.1.1 from 10.108.1.1 

      Origin IGP, metric 0, localpref 100, valid, external, best 

router-in-AS2501# show ip bgp 10.0.0.0 

BGP routing table entry for 10.0.0.0/8, version 3 

Paths: (1 available, best #1) 

  Not advertised to any peer 

  2 

    172.16.2.32 from 172.16.2.32 

      Origin IGP, metric 0, localpref 100, valid, external, best 

Related Commands

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} route-map map-name {in | out}

no neighbor {ip-address | peer-group-name} route-map map-name {in | out}

Syntax Description

Defaults

No route maps are applied to a peer.

Command Modes

Address family configuration

Router configuration

Command History

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 IP Version 4 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.

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 100

The 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 100

Related Commands

neighbor route-reflector-client

To configure the router as a BGP route reflector and configure the specified neighbor as its client, use the neighbor route-reflector-client command in address family or router configuration mode. To indicate that the neighbor is not a client, use the no form of this command.

neighbor ip-address route-reflector-client

no neighbor ip-address route-reflector-client

Syntax Description

Defaults

There is no route reflector in the autonomous system.

Command Modes

Address family configuration

Router configuration

Command History

Usage Guidelines

By default, all internal BGP (iBGP) speakers in an autonomous system must be fully meshed, and neighbors do not readvertise iBGP learned routes to neighbors, thus preventing a routing information loop. When all the clients are disabled, the local router is no longer a route reflector.

If you use route reflectors, all iBGP speakers need not be fully meshed. In the route reflector model, an Interior BGP peer is configured to be a route reflector responsible for passing iBGP learned routes to iBGP neighbors. This scheme eliminates the need for each router to talk to every other router.

Use the neighbor route-reflector-client command to configure the local router as the route reflector and the specified neighbor as one of its clients. All the neighbors configured with this command will be members of the client group and the remaining iBGP peers will be members of the nonclient group for the local route reflector.

The bgp client-to-client reflection command controls client-to-client reflection.

Examples

In the following router configuration mode example, the local router is a route reflector. It passes learned iBGP routes to the neighbor at 172.16.70.24.

router bgp 5

 neighbor 172.16.70.24 route-reflector-client

In the following address family configuration mode example, the local router is a route reflector. It passes learned iBGP routes to the neighbor at 172.16.70.24.

router bgp 5

address-family ipv4 unicast

 neighbor 172.16.70.24 route-reflector-client

Related Commands

neighbor send-community

To specify that a communities attribute should be sent to a BGP neighbor, use the neighbor send-community command in address family or router configuration mode. To remove the entry, use the no form of this command.

neighbor {ip-address | peer-group-name} send-community [both | standard | extended]

no neighbor {ip-address | peer-group-name} send-community

Syntax Description

Defaults

No communities attribute is sent to any neighbor.

Command Modes

Address family configuration

Router configuration

Command History

Usage Guidelines

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

In the following router configuration mode example, the router belongs to autonomous system 109 and is configured to send the communities attribute to its neighbor at IP address 172.16.70.23:

router bgp 109

 neighbor 172.16.70.23 send-community

In the following address family configuration mode example, the router belongs to autonomous system 109 and is configured to send the communities attribute to its neighbor at IP address 172.16.70.23:

router bgp 109

address-family ipv4 multicast

 neighbor 172.16.70.23 send-community

Related Commands

neighbor shutdown

To disable a neighbor or peer group, use the neighbor shutdown command in router configuration mode. To reenable the neighbor or peer group, use the no form of this command.

neighbor {ip-address | peer-group-name} shutdown

no neighbor {ip-address | peer-group-name} shutdown

Syntax Description

Defaults

No change is made to the status of any BGP neighbor or peer group.

Command Modes

Router configuration

Command History

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.

Examples

The following example disables any active session for the neighbor 172.16.70.23:

neighbor 172.16.70.23 shutdown

The following example disables all peering sessions for the peer group named internal:

neighbor internal shutdown

Related Commands

neighbor 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 no form of this command.

neighbor {ip-address | peer-group-name} soft-reconfiguration [inbound]

no neighbor {ip-address | peer-group-name} soft-reconfiguration [inbound]

Syntax Description

Defaults

Soft reconfiguration is not enabled.

Command Modes

Router configuration

Command History

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 be used only 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 {* | ip-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 neighbors command. 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 inbound

Related Commands

neighbor timers

To set the timers for a specific BGP peer or peer group, use the neighbor timers command in router configuration mode. To clear the timers for a specific BGP peer or peer group, use the no form of this command.

neighbor [ip-address | peer-group-name] timers keepalive holdtime

no neighbor [ip-address | peer-group-name] timers keepalive holdtime

Syntax Description

Defaults

keepalive: 60 seconds

holdtime: 180 seconds

Command Modes

Router configuration

Command History

Usage Guidelines

The timers configured for a specific neighbor or peer group override the timers configured for all BGP neighbors using the timers bgp command.

Examples

The following example changes the keepalive timer to 70 seconds and the hold-time timer to 210 seconds for the BGP peer 192.98.47.0:

router bgp 109 
 neighbor 192.98.47.0 timers 70 210

neighbor 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

Syntax Description

Command Default

No routes are unsuppressed.

Command Modes

Address family configuration
Router configuration

Command History

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 internal-map 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 activate

The 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-map

Related Commands

neighbor update-source

To have the Cisco IOS software allow Border Gateway Protocol (BGP) sessions to use a specific 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 | peer-group-name} update-source interface-type

no neighbor {ip-address | peer-group-name} update-source interface-type

Syntax Description

Defaults

Best local address

Command Modes

Router configuration

Command History

Usage Guidelines

This command works in conjunction with any specified interface on the router. The loopback interface is the interface that is most commonly used with this feature. For more information, refer to the loopback interface feature described in the "Interface Configuration Overview" chapter of the Cisco IOS Interface 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.

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 110

 network 172.16.0.0

 neighbor 172.16.2.3 remote-as 110 
 neighbor 172.16.2.3 update-source Loopback0

Related Commands

neighbor version

To configure the Cisco IOS software to accept only a particular BGP version, use the neighbor version command in router configuration mode. To use the default version level of a neighbor, use the no form of this command.

neighbor {ip-address | peer-group-name} version number

no neighbor {ip-address | peer-group-name} version number

Syntax Description

Defaults

BGP Version 4

Command Modes

Router configuration

Command History

Usage Guidelines

Entering this command disables dynamic version negotiation.

Note The Cisco implementation of BGP in Cisco IOS Release 12.0(5)T or earlier releases supports BGP Versions 2, 3, and 4, with dynamic negotiation down to Version 2 if a neighbor does not accept BGP Version 4 (the default version).

The Cisco implementation of BGP in Cisco IOS Release 12.0(6)T or later releases supports BGP Version 4 only and does not support dynamic negotiation down to Version 2.

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 locks down to Version 4 of the BGP protocol:

router bgp 109 
 neighbor 131.104.27.2 version 4

Related Commands

neighbor weight

To assign a weight to a neighbor connection, use the neighbor weight command in address family or router configuration mode. To remove a weight assignment, use the no form of this command.

neighbor {ip-address | peer-group-name} weight number

no neighbor {ip-address | peer-group-name} weight number

Syntax Description

Defaults

Routes learned through another BGP peer have a default weight of 0 and routes sourced by the local router have a default weight of 32768.

Command Modes

Address family configuration

Router configuration

Command History

Usage Guidelines

All routes learned from this neighbor will have the assigned weight initially. The route with the highest weight will be chosen as the preferred route when multiple routes are available to a particular network.

The weights assigned with the set weight route-map command override the weights assigned using the neighbor weight command.

Note For weight changes to take effect, use of the clear ip bgp peer-group * command may be necessary.

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 weight of all routes learned via 172.16.12.1 to 50:

router bgp 109 
 neighbor 172.16.12.1 weight 50

The following address family configuration mode example sets the weight of all routes learned via 172.16.12.1 to 50:

router bgp 109

address-family ipv4 multicast 
 neighbor 172.16.12.1 weight 50

Related Commands

network (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, use the no form of this command.

network network-number [mask network-mask] [route-map map-name]

no network network-number [mask network-mask] [route-map map-name]

Syntax Description

Defaults

No networks are specified.

Command Modes

Address family configuration
Router configuration

Command History

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0. The limit of 200 network commands per BGP router was removed in Cisco IOS Release 12.0. The maximum number of network commands you can use is now determined by the resources of the router, such as the amount of configured NVRAM or RAM.

For the information to be advertised by BGP or multiprotocol BGP, a route to the network specified must be present in the routing table. The routing information may be learned from connected routes, dynamic routing, and from static route sources.

Use the route-map keyword to apply a route map to a network to be advertised by the BGP and multiprotocol BGP routing processes. The specified route map can be used in filtering the network, or in setting attributes on the routes advertised by the network command.

Examples

The following example sets up network 10.108.0.0 to be included in the BGP updates:

router bgp 65000

 network 10.108.0.0

The following example sets up network 10.108.0.0 to be included in the multiprotocol BGP updates:

router bgp 65000

address family ipv4 multicast

 network 10.108.0.0

The following example shows the use of the mask keyword:

router bgp 65001

 network 10.0.0.0 

 mask 255.0.0.0 

 ! 

ip route 10.0.0.0 255.0.0.0 null0 

Note This configuration will advertise a supernet 10.0.0.0/8. It is necessary to use a static route to provide the information because this summary route may not be learned through dynamic routing or from a connected interface. Specifying the null 0 interface with the ip route command guarantees that the routing information will always be present in the routing table.

Related Commands

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.

network ip-address backdoor

no network ip-address backdoor

Syntax Description

Defaults

No network is marked as having a back door.

Command Modes

Address family configuration

Router configuration

Command History

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 back door network is treated as a local network, except that it is not advertised. A network that is marked as a backdoor 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 backdoor

The 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 backdoor

Related Commands

router bgp

To configure the BGP routing process, use the router bgp command in global configuration mode. To remove a routing process, use the no form of this command.

router bgp as-number

no router bgp as-number

Syntax Description

Defaults

No BGP routing process is enabled by default.

Command Modes

Global configuration

Command History

Usage Guidelines

This command allows you to set up a distributed routing core that automatically guarantees the loop-free exchange of routing information between autonomous systems.

Examples

The following example configures a BGP process for autonomous system 120:

router bgp 120

Related Commands

set as-path

To modify an autonomous system path for BGP routes, use the set as-path command in route-map configuration mode. To not modify the autonomous system path, use the no form of this command.

set as-path {tag | prepend as-path-string}

no set as-path {tag | prepend as-path-string}

Syntax Description

Defaults

Autonomous system path is not modified.

Command Modes

Route-map configuration

Command History

Usage Guidelines

The only global BGP metric available to influence the best path selection is the autonomous system path length. By varying the length of the autonomous system path, a BGP speaker can influence the best path selection by a peer further away.

By allowing you to convert the tag into an autonomous system path, the set as-path tag variation of this command modifies the autonomous system length. The set as-path prepend variation allows you to "prepend" an arbitrary autonomous system path string to BGP routes. Usually the local autonomous system number is prepended multiple times, increasing the autonomous system path length.

Examples

The following example converts the tag of a redistributed route into an autonomous system path:

route-map set-as-path-from-tag

 set as-path tag

!

router bgp 100

 redistribute ospf 109 route-map set-as-path-from-tag

The following example prepends 100 100 100 to all the routes advertised to 10.108.1.1:

route-map set-as-path

 match as-path 1

 set as-path prepend 100 100 100

!

router bgp 100

 neighbor 10.108.1.1 route-map set-as-path out

Related Commands

set comm-list delete

To remove communities from the community attribute of an inbound or outbound update, use the set comm-list delete command in route-map configuration mode. To negate a previous set comm-list delete command, use the no form of this command.

set comm-list community-list-number delete

no set comm-list community-list-number delete

Syntax Description

Defaults

No communities are removed.

Command Modes

Route-map configuration

Command History

Usage Guidelines

This route-map set command removes communities from the community attribute of an inbound or outbound update using a route map to filter and determine the communities to be deleted. Depending upon whether the route map is applied to the inbound or outbound update for a neighbor, each community that passes the route map permit clause and matches the given community list will be removed from the community attribute being received from or sent to the BGP neighbor.

Each entry of a standard community list should list only one community when used with the set comm-list delete command. For example, in order to be able to delete communities 10:10 and 10:20, you must use the following format to create the entries:

ip community-list 5 permit 10:10 
ip community-list 5 permit 10:20

The following format for a community list entry, while acceptable otherwise, does not work with the set comm-list delete command:

config ip community-list 5 permit 10:10 10:20

When both the set community community-list-number and set comm-list delete commands are configured in the same sequence of a route map attribute, the deletion operation (set comm-list delete) is performed before the set operation (set community community-list-number).

Examples

In the following example, the communities 100:10 and 100:20 (if present) will be deleted from updates received from 171.69.233.33. Also, except for 100:50, all communities beginning with 100: will be deleted from updates sent to 171.69.233.33.

router bgp 100 
 neighbor 171.69.233.33 remote-as 120 
 neighbor 171.69.233.33 route-map ROUTEMAPIN in 
 neighbor 171.69.233.33 route-map ROUTEMAPOUT out 
! 
ip community-list 1 permit 100:10 
ip community-list 1 permit 100:20 
! 
ip community-list 120 deny   100:50 
ip community-list 120 permit 100:.* 
! 
route-map ROUTEMAPIN permit 10 
 set comm-list 1 delete 
! 
route-map ROUTEMAPOUT permit 10 
 set comm-list 120 delete

Related Commands

set community

To set the BGP communities attribute, use the set community route map configuration command. To delete the entry, use the no form of this command.

set community {community-number [additive]} | none

no set community {community-number [additive]} | none

Syntax Description

Defaults

No BGP communities attributes exist.

Command Modes

Route-map configuration

Command History

Usage Guidelines

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command, and the match and set route map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route map configuration commands specify the redistribution set actions to be performed when all of the match criteria of a route map are met. When all match criteria are met, all set actions are performed.

Examples

In the following example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to no-export (these routes will not be advertised to any external BGP [eBGP] peers).

route-map set_community 10 permit

 match as-path 1

 set community 109

route-map set_community 20 permit

 match as-path 2

 set community no-export

In the following similar example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to local-as (the router will not advertise this route to peers outside the local autonomous system.

route-map set_community 10 permit

 match as-path 1

 set community 109

route-map set_community 20 permit

 match as-path 2

 set community local-as

Related Commands

set dampening

To set the BGP route dampening factors, use the set dampening route map configuration command. To disable this function, use the no form of this command.

set dampening half-life reuse suppress max-suppress-time

no set dampening

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Route-map configuration

Command History

Usage Guidelines

Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

When a BGP peer is reset, the route is withdrawn and the flap statistics cleared. In this instance, the withdrawal does not incur a penalty even though route flap dampening is enabled.

Examples

The following example sets the half life to 30 minutes, the reuse value to 1500, the suppress value to 10000; and the maximum suppress time to 120 minutes:

route-map tag

 match as path 10

 set dampening 30 1500 10000 120

!

router bgp 100

 neighbor 171.69.233.52 route-map tag in

Related Commands

set extcommunity

To set Border Gateway Protocol (BGP) extended community attributes, use the set extcommunity command in route-map configuration mode. To delete the entry, use the no form of this command.

set extcommunity {rt extended-community-value [additive] | soo extended-community-value}

no set extcommunity {rt extended-community-value [additive] | soo extended-community-value}

Syntax Description

Defaults

Specifying new route targets with the rt keyword replaces existing route targets by default, unless the additive keyword is used. The use of the additive keyword adds the new route target to the existing route target list but does not replace any existing route targets.

Command Modes

Route-map configuration

Command History

Usage Guidelines

Extended community attributes are used to configure, filter, and identify routes for virtual routing and forwarding instances (VRFs) and Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs).

The set extcommunity command is used to configure set clauses that use extended community attributes in route maps. All of the standard rules of match and set clauses apply to the configuration of extended community attributes.

The route target (RT) extended community attribute is configured with the rt keyword. This attribute is used to identify a set of sites and VRFs that may receive routes that are tagged with the configured route target. Configuring the route target extended attribute with a route allows that route to be placed in the per-site forwarding tables that are used for routing traffic that is received from corresponding sites.

The site of origin (SOO) extended community attribute is configured with the soo keyword. This attribute uniquely identifies the site from which the Provider Edge (PE) router learned the route. All routes learned from a particular site must be assigned the same SOO extended community attribute, whether a site is connected to a single PE router or multiple PE routers. Configuring this attribute prevents routing loops from occurring when a site is multihomed. The SOO extended community attribute is configured on the interface and is propagated into BGP through redistribution. The SOO can be applied to routes that are learned from VRFs. The SOO should not be configured for stub sites or sites that are not multihomed.

Examples

The following example sets the route target to extended community attribute 100:2 for routes that are permitted by the route map:

Router(config)# access-list 2 permit 192.168.78.0 255.255.255.0

Router(config)# route-map MAP_NAME permit 10

Router(config-route-map)# match ip-address 2

Router(config-route-map)# set extcommunity rt 100:2

The following example sets the route target to extended community attribute 100:3 for routes that are permitted by the route map. The use of the additive keyword adds route target 100:3 to the existing route target list but does not replace any existing route targets.

Router(config)# access-list 3 permit 192.168.79.0 255.255.255.0

Router(config)# route-map MAP_NAME permit 10

Router(config-route-map)# match ip-address 3

Router(config-route-map)# set extcommunity rt 100:3 additive

Note Configuring route targets with the set extcommunity command will replace existing route targets, unless the additive keyword is used.

The following example sets the site of origin to extended community attribute 100:4 for routes that are permitted by the route map:

Router(config)# access-list 4 permit 192.168.80.0 255.255.255.0

Router(config)# route-map MAP_NAME permit 10

Router(config-route-map)# match ip-address 4

Router(config-route-map)# set extcommunity soo 100:4

Related Commands

set ip next-hop (BGP)

To indicate where to output packets that pass a match clause of a route map for policy routing, use the set ip next-hop command in route-map configuration mode. To delete an entry, use the no form of this command.

set ip next-hop ip-address [... ip-address] [peer-address]

no set ip next-hop ip-address [... ip-address] [peer-address]

Syntax Description

Defaults

This command is disabled by default.

Command Modes

Route-map configuration

Command History

Usage Guidelines

An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the ip-address argument.

Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.

If the interface associated with the first next hop specified with the set ip next-hop command is down, the optionally specified IP addresses are tried in turn.

When the set ip next-hop command is used with the peer-address keyword in an inbound route map of a BGP peer, the next hop of the received matching routes will be set to be the neighbor peering address, overriding any third-party next hops. So the same route map can be applied to multiple BGP peers to override third-party next hops.

When the set ip next-hop command is used with the peer-address keyword in an outbound route map of a BGP peer, the next hop of the advertised matching routes will be set to be the peering address of the local router, thus disabling the next hop calculation. The set ip next-hop command has finer granularity than the per-neighbor neighbor next-hop-self command, because you can set the next hop for some routes, but not others. The neighbor next-hop-self command sets the next hop for all routes sent to that neighbor.

The set clauses can be used in conjunction with one another. They are evaluated in the following order:

1. set ip next-hop

2. set interface

3. set ip default next-hop

4. set default interface

Examples

In the following example, three routers are on the same FDDI LAN (with IP addresses 10.1.1.1, 10.1.1.2, and 10.1.1.3). Each is in a different autonomous system. The set ip next-hop peer-address command specifies that traffic from the router (10.1.1.3) in remote autonomous system 300 for the router (10.1.1.1) in remote autonomous system 100 that matches the route map is passed through the router bgp 200, rather than sent directly to the router (10.1.1.1) in autonomous system 100 over their mutual connection to the LAN.

router bgp 200

neighbor 10.1.1.3 remote-as 300

neighbor 10.1.1.3 route-map set-peer-address out

neighbor 10.1.1.1 remote-as 100

route-map set-peer-address permit 10

set ip next-hop peer-address

Related Commands

set metric-type internal

To set the Multi Exit Discriminator (MED) value on prefixes advertised to external BGP (eBGP) neighbors to match the Interior Gateway Protocol (IGP) metric of the next hop, use the set metric-type internal command in route-map configuration mode. To return to the default, use the no form of this command.

set metric-type internal

no set metric-type internal

Syntax Description

This command has no arguments or keywords.

Defaults

This command is disabled by default.

Command Modes

Route-map configuration

Command History

Usage Guidelines

This command will cause BGP to advertise a MED value that corresponds to the IGP metric associated with the next hop of the route. This command applies to generated, internal BGP (iBGP)-, and eBGP-derived routes.

If this command is used, multiple BGP speakers in a common autonomous system can advertise different MED values for a particular prefix. Also, note that if the IGP metric changes, BGP will readvertise the route every 10 minutes.

Use the route-map global configuration command and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria of the route map are met. When all match criteria are met, all set actions are performed.

Note This command is not supported for redistributing routes into Border Gateway Protocol (BGP).

Examples

In the following example, the MED value for all the advertised routes to neighbor 172.16.2.3 is set to the corresponding IGP metric of the next hop:

router bgp 109

 network 172.16.0.0

 neighbor 172.16.2.3 remote-as 200

 neighbor 172.16.2.3 route-map setMED out

!

route-map setMED permit 10

 match as-path 1

 set metric-type internal

!

 ip as-path access-list 1 permit .*

Related Commands

set origin (BGP)

To set the BGP origin code, use the set origin command in route-map configuration mode. To delete an entry, use the no form of this command.

set origin {igp | egp as-number | incomplete}

no set origin {igp | egp as-number | incomplete}

Syntax Description

Defaults

Default origin, based on route in main IP routing table

Command Modes

Route-map configuration

Command History

Usage Guidelines

You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.

Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.

The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria of a route map are met. When all match criteria are met, all set actions are performed.

Examples

The following example sets the origin of routes that pass the route map to IGP:

route-map set_origin

 match as-path 10

 set origin igp

Related Commands

set weight

To specify the BGP weight for the routing table, use the set weight command in route-map configuration mode. To delete an entry, use the no form of this command.

set weight number

no set weight number

Syntax Description

Defaults

The weight is not changed by the specified route map.

Command Modes

Route-map configuration

Command History

Usage Guidelines

The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the set weight route-map configuration command override the weights assigned using the neighbor weight command.

Examples

The following example sets the BGP weight for the routes matching the autonomous system path access list to 200:

route-map set-weight

 match as-path 10

 set weight 200

Related Commands

show ip bgp

To display entries in the Border Gateway Protocol (BGP) routing table, use the show ip bgp command in command in EXEC mode.

show ip bgp [ip-address [mask [longer-prefixes [injected] | shorter-prefixes [length]]] | oer-paths | prefix-list name | route-map name]

Syntax Description

Command Modes

EXEC

Command History

Usage Guidelines

The show ip bgp command is used to display the contents of the BGP routing table. The output can be filtered to display entries for a specific prefix, prefix length, and prefixes injected through a prefix list, route map, or conditional advertisement.

oer-paths keyword

BGP prefixes that are monitored and controlled by Optimized Edge Routing (OER) are displayed by entering the show ip bgp command with the oer-paths keyword.

Examples

show ip bgp example

The following example output shows the BGP routing table:

Router# show ip bgp

BGP table version is 5, local router ID is 10.0.33.34

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path

*> 10.1.0.0          0.0.0.0                  0         32768 ?

*  10.2.0.0          10.0.33.35              10             0 35 ?

*>                   0.0.0.0                  0         32768 ?

*  10.0.0.0         10.0.33.35               10             0 35 ?

*>                   0.0.0.0                  0         32768 ?

*> 192.168.0.0/16   10.0.33.35               10             0 35 ? 

Table 32 describes the significant fields shown in the display.

show ip bgp ip-address example

The following example displays information about the 192.168.1.0 entry in the BGP routing table:

Router B# show ip bgp 192.168.1.0 

BGP routing table entry for 192.168.1.0/24, version 48

Paths: (2 available, best #2, table Default-IP-Routing-Table)

Multipath: eBGP

  Advertised to update-groups:

     1          2

  200

    172.16.1.1 from 172.16.1.1 (10.1.1.1)

      Origin incomplete, metric 0, localpref 100, valid, external, multipath, best

      Extended Community: 0x0:0:0

      DMZ-Link Bw 278 kbytes

  200

    172.16.2.2 from 172.16.2.2 (10.2.2.2)

      Origin incomplete, metric 0, localpref 100, valid, external, multipath, best

      Extended Community: 0x0:0:0

      DMZ-Link Bw 625 kbytes 

Table 33 describes the significant fields shown in the display.

show ip bgp longer-prefixes example

The following is example output from the show ip bgp command entered with the longer-prefixes keyword:

Router# show ip bgp 10.92.0.0 255.255.0.0 longer-prefixes

BGP table version is 1738, local router ID is 192.168.72.24

Status codes: s suppressed, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop          Metric LocPrf Weight Path

*> 10.92.0.0         10.92.72.30        8896         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.1.0         10.92.72.30        8796         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.11.0        10.92.72.30       42482         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.14.0        10.92.72.30        8796         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.15.0        10.92.72.30        8696         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.16.0        10.92.72.30        1400         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.17.0        10.92.72.30        1400         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.18.0        10.92.72.30        8876         32768 ?

*                    10.92.72.30                         0 109 108 ?

*> 10.92.19.0        10.92.72.30        8876         32768 ?

*                    10.92.72.30                         0 109 108 ?

show ip bgp shorter-prefixes example

The following is example output from the show ip bgp command entered with the shorter-prefixes keyword. An 8 bit prefix length is specified.

Router# show ip bgp 172.16.0.0/16 shorter-prefixes 8

*> 172.16.0.0         10.0.0.2                               0 ?

*                     10.0.0.2                 0             0 200 ?

show ip bgp prefix-list example

The following is example output from the show ip bgp command entered with the prefix-list keyword:

Router# show ip bgp prefix-list ROUTE

BGP table version is 39, local router ID is 10.0.0.1

Status codes:s suppressed, d damped, h history, * valid, > best, i -

internal

Origin codes:i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path

*> 192.168.1.0      10.0.0.2                               0 ?

*                   10.0.0.2                 0             0 200 ?

show ip bgp route-map example

The following is example output from the show ip bgp command entered with the route-map keyword:

Router# show ip bgp route-map LEARNED_PATH

BGP table version is 40, local router ID is 10.0.0.1

Status codes:s suppressed, d damped, h history, * valid, > best, i -

internal

Origin codes:i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path

*> 192.168.1.0      10.0.0.2                               0 ?

*                   10.0.0.2                 0             0 200 ?

show ip bgp cidr-only

To display routes with nonnatural network masks (that is, classless interdomain routing, or CIDR), use the show ip bgp cidr-only command in EXEC mode.

show ip bgp cidr-only

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Examples

The following is sample output from the show ip bgp cidr-only command in privileged EXEC mode:

Router# show ip bgp cidr-only

BGP table version is 220, local router ID is 172.16.73.131

Status codes: s suppressed, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop          Metric LocPrf Weight Path

*> 192.168.0.0/8    172.16.72.24                         0 1878 ?

*> 172.16.0.0/16    172.16.72.30                         0 108 ?

Table 34 describes the significant fields shown in the display.

show ip bgp community

To display routes that belong to specified BGP communities, use the show ip bgp community command in EXEC mode.

show ip bgp community community-number [exact]

Syntax Description

Command Modes

EXEC

Command History

Examples

The following is sample output from the show ip bgp community command in privileged EXEC mode:

router# show ip bgp community 111:12345 local-as

 BGP table version is 10, local router ID is 224.0.0.10

 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal

 Origin codes: i - IGP, e - EGP, ? - incomplete

    Network          Next Hop          Metric LocPrf Weight Path

 *> 172.16.2.2/32    172.43.222.2           0             0 222 ?

 *> 10.0.0.0         172.43.222.2           0             0 222 ?

 *> 172.43.0.0       172.43.222.2           0             0 222 ?

 *> 172.43.44.44/32  172.43.222.2           0             0 222 ?

 *  172.43.222.0/24  172.43.222.2           0             0 222 i

 *> 172.17.240.0/21  172.43.222.2           0             0 222 ?

 *> 192.168.212.0    172.43.222.2           0             0 222 i

 *> 172.39.1.0       172.43.222.2           0             0 222 ?

Table 35 describes the significant fields shown in the display.

show ip bgp community-list

To display routes that are permitted by the BGP community list, use the show ip bgp community-list command in EXEC mode.

show ip bgp community-list community-list-number [exact]

Syntax Description

Command Modes

EXEC

Command History

Examples

The following is sample output of the show ip bgp community-list command in privileged EXEC mode:

Router# show ip bgp community-list 20

BGP table version is 716977, local router ID is 193.0.32.1

Status codes: s suppressed, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop          Metric LocPrf Weight Path

* i3.0.0.0          193.0.22.1             0    100      0 1800 1239 ?

*>i                 193.0.16.1             0    100      0 1800 1239 ?

* i6.0.0.0          193.0.22.1             0    100      0 1800 690 568 ?

*>i                 193.0.16.1             0    100      0 1800 690 568 ?

* i7.0.0.0          193.0.22.1             0    100      0 1800 701 35 ?

*>i                 193.0.16.1             0    100      0 1800 701 35 ?

*                   172.16.72.24                         0 1878 704 701 35 ?

* i8.0.0.0          193.0.22.1             0    100      0 1800 690 560 ?

*>i                 193.0.16.1             0    100      0 1800 690 560 ?

*                   172.16.72.24                         0 1878 704 701 560 ?

* i13.0.0.0         193.0.22.1             0    100      0 1800 690 200 ?

*>i                 193.0.16.1             0    100      0 1800 690 200 ?

*                   172.16.72.24                         0 1878 704 701 200 ?

* i15.0.0.0         193.0.22.1             0    100      0 1800 174 ?

*>i                 193.0.16.1             0    100      0 1800 174 ?

* i16.0.0.0         193.0.22.1             0    100      0 1800 701 i

*>i                 193.0.16.1             0    100      0 1800 701 i

*                   172.16.72.24                         0 1878 704 701 i

Table 36 describes the significant fields shown in the display.

show ip bgp dampened-paths

To display BGP dampened routes, use the show ip bgp dampened-paths command in EXEC mode.

show ip bgp dampened-paths

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Examples

The following is sample output from the show ip bgp dampened-paths command in privileged EXEC mode:

Router# show ip bgp dampened-paths

BGP table version is 10, local router ID is 171.69.232.182

Status codes: s suppressed, d damped, h history, * valid, > best, i -

internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          From             Reuse   Path

*d 10.0.0.0         171.69.232.177   00:18:4 100 ?

*d 12.0.0.0         171.69.232.177   00:28:5 100 ?

Table 37 describes the significant fields shown in the display.

Related Commands

show ip bgp filter-list

To display routes that conform to a specified filter list, use the show ip bgp filter-list command in EXEC mode.

show ip bgp filter-list access-list-number

Syntax Description

Command Modes

EXEC

Command History

Examples

The following is sample output from the show ip bgp filter-list command in privileged EXEC mode:

Router# show ip bgp filter-list 2

BGP table version is 1738, local router ID is 172.16.72.24

Status codes: s suppressed, * valid, > best, i - internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop          Metric LocPrf Weight Path

*  172.16.0.0       172.16.72.30                         0 109 108 ?

*  172.16.1.0       172.16.72.30                         0 109 108 ?

*  172.16.11.0      172.16.72.30                         0 109 108 ?

*  172.16.14.0      172.16.72.30                         0 109 108 ?

*  172.16.15.0      172.16.72.30                         0 109 108 ?

*  172.16.16.0      172.16.72.30                         0 109 108 ?

*  172.16.17.0      172.16.72.30                         0 109 108 ?

*  172.16.18.0      172.16.72.30                         0 109 108 ?

*  172.16.19.0      172.16.72.30                         0 109 108 ?

*  172.16.24.0      172.16.72.30                         0 109 108 ?

*  172.16.29.0      172.16.72.30                         0 109 108 ?

*  172.16.30.0      172.16.72.30                         0 109 108 ?

*  172.16.33.0      172.16.72.30                         0 109 108 ?

*  172.16.35.0      172.16.72.30                         0 109 108 ?

*  172.16.36.0      172.16.72.30                         0 109 108 ?

*  172.16.37.0      172.16.72.30                         0 109 108 ?

*  172.16.38.0      172.16.72.30                         0 109 108 ?

*  172.16.39.0      172.16.72.30                         0 109 108 ?

Table 38 describes the significant fields shown in the display.

show ip bgp flap-statistics

To display BGP flap statistics, use the show ip bgp flap-statistics command in EXEC mode.

show ip bgp flap-statistics [{regexp regexp} | {filter-list access-list} | {ip-address mask [longer-prefix]}]

Syntax Description

Command Modes

EXEC

Command History

Usage Guidelines

If no arguments or keywords are specified, the router displays flap statistics for all routes.

Examples

The following is sample output from the show ip bgp flap-statistics command in privileged EXEC mode:

Router# show ip bgp flap-statistics

BGP table version is 10, local router ID is 171.69.232.182

Status codes: s suppressed, d damped, h history, * valid, > best, i -

internal

Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          From            Flaps Duration Reuse    Path

*d 10.0.0.0         171.69.232.177  4     00:13:31 00:18:10 100

*d 12.0.0.0         171.69.232.177  4     00:02:45 00:28:20 100

Table 39 describes the significant fields shown in the display.

Related Commands

show ip bgp inconsistent-as

To display routes with inconsistent originating autonomous systems, use the show ip bgp inconsistent-as command in EXEC mode.

show ip bgp inconsistent-as

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History