Basic BGP configuration

This section provides information to configure BGP and configuration examples of common configuration tasks. The minimal BGP parameters that need to be configured are:

An autonomous system number for the router.
A router ID - Note that if a new or different router ID value is entered in the BGP context, then the new valued takes precedence and overwrites the router-level router ID.
A BGP peer group.
A BGP neighbor with which to peer.
A BGP peer-AS that is associated with the preceding peer.

The BGP configuration commands have three primary configuration levels: bgp for global configurations, group name for BGP group configuration, and neighbor ip-addressfor BGP neighbor configuration. Within the different levels, many of the configuration commands are repeated. For the repeated commands, the command that is most specific to the neighboring router is in effect, that is, neighbor settings have precedence over group settings which have precedence over BGP global settings.

Example

The following is a sample configuration that includes the preceding parameters. The following parameters are optional.

info
#--------------------------------------------------
echo "IP Configuration"
#--------------------------------------------------
...
        autonomous-system 200
        router-id 10.10.10.103
#--------------------------------------------------
...
#--------------------------------------------------
echo "BGP Configuration"
#--------------------------------------------------
        bgp
            exit
            
            export "direct2bgp"
            router-id 10.0.0.12
            group "To_AS_10000"
                connect-retry 20
                hold-time 90
                keepalive 30
                local-preference 100
                remove-private
                peer-as 10000
                neighbor 10.0.0.8
                    description "To_Router B - EBGP Peer"
                    connect-retry 20
                    hold-time 90
                    keepalive 30
                    local-address 10.0.0.12
                    passive
                    preference 99
                    peer-as 10000
                exit
            exit
            group "To_AS_30000"
                connect-retry 20
                hold-time 90
                keepalive 30
                local-preference 100
                remove-private
                peer-as 30000
                neighbor 10.0.3.10
                    description "To_Router C - EBGP Peer"
                    connect-retry 20
                    hold-time 90
                    keepalive 30
                    peer-as 30000
                exit
            exit
            group "To_AS_40000"
                connect-retry 20
                hold-time 30
                keepalive 30
                local-preference 100
                peer-as 65206
                neighbor 10.0.0.15
 
 description "To_Router E - Sub Confederation AS 65205"
                    connect-retry 20
                    hold-time 90
                    keepalive 30
                    local-address 10.0.0.12
                    peer-as 65205
                exit
            exit
        exit
#--------------------------------------------------
....
A:ALA-48>config>router#