Command:

neighbor peer-group (creating)


Mode:

Router(config-router)#

Router(config-router-af)#


Syntax:

neighbor peer-group-name peer-group
no neighbor peer-group-name peer-group

 

Syntax Description:

peer-group-name Name of the BGP peer group.

 

Command Description:

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.

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.

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.


Example:

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(config)# router bgp 100
Router(config-router)# neighbor internal peer-group 
Router(config-router)# neighbor internal remote-as 100
Router(config-router)# neighbor internal update-source loopback 0
Router(config-router)# neighbor internal route-map set-med out
Router(config-router)# neighbor internal filter-list 1 out
Router(config-router)# neighbor internal filter-list 2 in
Router(config-router)# neighbor 171.69.232.53 peer-group internal
Router(config-router)# neighbor 171.69.232.54 peer-group internal
Router(config-router)# neighbor 171.69.232.55 peer-group internal
Router(config-router)# 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
Router(config-router)# neighbor external-peers peer-group 
Router(config-router)# neighbor external-peers route-map set-metric out
Router(config-router)# neighbor external-peers filter-list 99 out
Router(config-router)# neighbor external-peers filter-list 101 in
Router(config-router)# neighbor 171.69.232.90 remote-as 200
Router(config-router)# neighbor 171.69.232.90 peer-group external-peers
Router(config-router)# neighbor 171.69.232.100 remote-as 300
Router(config-router)# neighbor 171.69.232.100 peer-group external-peers
Router(config-router)# neighbor 171.69.232.110 remote-as 400
Router(config-router)# neighbor 171.69.232.110 peer-group external-peers
Router(config-router)# 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(config-router)# router bgp 100
Router(config-router)# neighbor 10.1.1.1 remote-as 1
Router(config-router)# neighbor 172.16.2.2 remote-as 2
Router(config-router)# address-family ipv4 multicast
Router(config-router-af)# neighbor mygroup peer-group 
Router(config-router-af)# neighbor 10.1.1.1 peer-group mygroup
Router(config-router-af)# neighbor 172.16.2.2 peer-group mygroup
Router(config-router-af)# neighbor 10.1.1.1 activate
Router(config-router-af)# neighbor 172.16.2.2 activate


Misconceptions:

Peer group members can span multiple logical IP subnets, and can transmit, or pass along, routes from one peer group member to another.


Related Commands:

address-family ipv4
neighbor peer-group (assigning members)

� Cisco Systems, Inc. 2001, 2002, 2003
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