Administrator Guide

To add an external BGP (EBGP) neighbor, configure the as-number parameter with a number different from the BGP
as-number configured in the router bgp as-number command.
To add an internal BGP (IBGP) neighbor, configure the as-number parameter with the same BGP as-number configured in
the router bgp as-number command.
After you create a peer group, you can use any of the commands beginning with the keyword neighbor to configure that peer
group.
When you add a peer to a peer group, it inherits all the peer group’s configured parameters.
A neighbor cannot become part of a peer group if it has any of the following commands configured:
● neighbor advertisement-interval
● neighbor distribute-list out
● neighbor filter-list out
● neighbor next-hop-self
● neighbor route-map out
● neighbor route-reflector-client
● neighbor send-community
A neighbor may keep its configuration after it was added to a peer group if the neighbor’s configuration is more specific than
the peer group’s and if the neighbor’s configuration does not affect outgoing updates.
NOTE: When you configure a new set of BGP policies for a peer group, always reset the peer group by entering the clear
ip bgp peer-group peer-group-name command in EXEC Privilege mode.
To view the configuration, use the show config command in CONFIGURATION ROUTER BGP mode.
When you create a peer group, it is disabled (shutdown). The following example shows the creation of a peer group (zanzibar)
(in bold).
Dell(conf-router_bgp)#neighbor zanzibar peer-group
Dell(conf-router_bgp)#show conf
!
router bgp 45
bgp fast-external-fallover
bgp log-neighbor-changes
neighbor zanzibar peer-group
neighbor zanzibar shutdown
neighbor 10.1.1.1 remote-as 65535
neighbor 10.1.1.1 shutdown
neighbor 10.14.8.60 remote-as 18505
neighbor 10.14.8.60 no shutdown
Dell(conf-router_bgp)#
To enable a peer group, use the neighbor peer-group-name no shutdown command in CONFIGURATION ROUTER
BGP mode (shown in bold).
Dell(conf-router_bgp)#neighbor zanzibar no shutdown
Dell(conf-router_bgp)#show config
!
router bgp 45
bgp fast-external-fallover
bgp log-neighbor-changes
neighbor zanzibar peer-group
neighbor zanzibar no shutdown
neighbor 10.1.1.1 remote-as 65535
neighbor 10.1.1.1 shutdown
neighbor 10.14.8.60 remote-as 18505
neighbor 10.14.8.60 no shutdown
Dell(conf-router_bgp)#
To disable a peer group, use the neighbor peer-group-name shutdown command in CONFIGURATION ROUTER BGP
mode. The configuration of the peer group is maintained, but it is not applied to the peer group members. When you disable a
peer group, all the peers within the peer group that are in the ESTABLISHED state move to the IDLE state.
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Border Gateway Protocol IPv4 (BGPv4)