Establishing the MP-EBGP Peer Between PEs

With extended community attributes added to BGP, MP-IBGP can advertise VPNv4 routes between PEs. PEs of different ASs are indirectly connected in most cases. Therefore, to set up the EBGP connections between them, you need to configure the permitted maximum hops between the PEs and ensure that the PEs are reachable.

Procedure

Configure a PE to advertise its loopback interface IP addresses used for peer relationship establishment to the ASBRs of other ASs and peer PEs. You can also configure an ASBR to send the loopback interface IP addresses of a PE used for peer relationship establishment to the ASBRs of other ASs and peer PEs.

If you want to use inter-AS TE tunnels to transmit traffic in inter-AS Option C networking, perform the following steps on PEs, so that the loopback interface IP addresses of PEs used for peer relationship establishment can be advertised to peer PEs.
1. Run system-view
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  The BGP view is displayed.
3. Run network ip-address [ mask | mask-length ] [ route-policy route-policy-name ]
  The loopback address of the PE in the local AS is advertised to the remote ASBR.
4. Run commit
  The configuration is committed.
Perform the following steps on the PE that is connected to a CE:
1. Run system-view
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  The BGP view is displayed.
3. Run peer ipv4-address as-number { as-number-plain | as-number-dot }
  The peer PE is specified as the EBGP peer.
4. Run peer ipv4-address connect-interface loopback interface-number
  The source interface that sends BGP packets is specified.
5. Run peer ipv4-address ebgp-max-hop [ hop-count ]
  The maximum hop of the EBGP peer is set. PEs of different ASs are generally not directly connected. To set up the EBGP peer between PEs of different ASs, configure the maximum hop between PEs and ensure the PEs are reachable.
6. Run ipv6-family vpnv6
  The BGP-VPN IPv6 address family view is displayed.
7. Run peer ipv4-address enable
  The exchange of VPNv6 routes with the peer PE is enabled.
8. Run commit
  The configuration is committed.
(Optional) Configure a route reflector (RR).
To improve scalability, specify an RR in each AS and establish MP-EBGP peer relationships between the RRs in ASs to save all VPNv6 routes on the RRs. Then configure PEs in each AS as the RR's clients to exchange VPNv6 routing information with the RR. Perform the following steps on a device that needs to be configured as an RR:
1. Run system-view
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  The BGP view is displayed.
3. Run peer ipv4-address as-number { as-number-plain | as-number-dot }
  The RR in another AS is configured as its EBGP peer.
4. Run peer ipv4-address connect-interface loopback interface-number
  The source interface that sends BGP packets is specified.
5. Run peer ipv4-address ebgp-max-hop [ hop-count ]
  The maximum number of hops between RRs for which an EBGP peer relationship is to be configured is specified.
6. Run ipv6-family vpnv6
  The BGP-VPN IPv6 address family view is displayed.
7. Run peer ipv4-address enable
  The exchange of VPNv6 routes with the peer RR is enabled.
8. Run peer ipv4-address reflect-client
  The device is configured as an RR, and PEs are specified as its clients.
9. Run peer ipv4-address next-hop-invariable
  The next hop is not changed when the route is advertised to the EBGP peer.
10. Run peer ipv4-address next-hop-invariable
  The next hop is not changed when the route is advertised to the IBGP peer.
11. Run commit
  The configuration is committed.