Configuring BGP Peers

Context

During the configuration of BGP peers, if the AS number of the specified peer is the same as the local AS number, an IBGP peer is configured. If the AS number of the specified peer is different from the local AS number, an EBGP peer is configured. To enhance the stability of BGP connections, you are advised to use the reachable loopback interface addresses to establish BGP connections.

When loopback interface addresses are used to establish a BGP connection, run the peer connect-interface command on both ends of the BGP connection to ensure the correctness of interfaces and addresses on the TCP connection. If the command is run on only one end, the BGP connection may fail to be established.

When loopback interface addresses are used to establish an EBGP connection, the peer ebgp-max-hop command with hop-count greater than or equal to 2 must be run. Otherwise, the EBGP connection cannot be established.

To perform the same configuration on a large number of peers, configure a BGP peer group according to (Optional) Configuring a BGP Peer Group to reduce the configuration workload.

Procedure

Run system-view
The system view is displayed.
Run bgp { as-number-plain | as-number-dot }
The BGP view is displayed.
Run peer { ipv4-address | ipv6-address } as-number { as-number-plain | as-number-dot }
The BGP peer is created.

By default, no BGP peer is created.
(Optional) Run peer ipv4-address connect-interface interface-type interface-number [ ipv4-source-address ]
Or run peer ipv6-address connect-interface interface-type interface-number [ ipv6-source-address ]

A source interface and a source IP address are specified for the peer to establish a TCP connection.

By default, BGP uses the interface that is directly connected to the peer to establish a TCP connection.
(Optional) Run peer { ipv4-address | ipv6-address } ebgp-max-hop [ hop-count ]
The maximum number of hops allowed for the establishment of an EBGP connection is set.

By default, the maximum number of hops allowed for an EBGP connection is 1. That is, an EBGP connection must be established on a directly connected physical link.

If a one-hop EBGP peer relationship is established using loopback interface addresses, you can also run the peer connected-check-ignore command to establish an EBGP peer relationship.
(Optional) Run peer { ipv4-address | ipv6-address } description description-text
The description of the peer is configured.

If a BGP peer is configured on an IPv4 unicast network, steps 7 and 8 are not required. If a BGP peer is configured on an IPv4 multicast network and an IPv6 unicast network, steps 7 and 8 are required.
(Optional) Run the following commands as required.
- Run ipv4-family multicast
  The BGP-IPv4 multicast address family view is displayed.
- Run ipv6-family [ unicast ]
  The BGP-IPv6 unicast address family view is displayed.
(Optional) Run peer { ipv4-address | ipv6-address } enable
MP-BGP is enabled on the BGP peers to configure them as MP-BGP peers.