Enabling BGP Peers to Exchange Labeled IPv4 Routes

Procedure

• Perform the following steps on each CSG, AGG, and MASG:
  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 | group-name } label-route-capability [ check-tunnel-reachable ]

     The capability of exchanging labeled IPv4 routes with devices in the local AS is enabled.

     By default, the capability of exchanging labeled IPv4 routes is disabled.

     The check-tunnel-reachable parameter helps prevent a data forwarding failure when the CSG and MASG successfully set up an MP-EBGP peer relationship but a section along the LSP between them fails to be established.

     • If the check-tunnel-reachable parameter is specified:

       When a tunnel between a local and remote device is unreachable, the local device advertises an IPv4 unicast route to its peer. When the tunnel is reachable, the local device advertises a labeled IPv4 route.

     • If the check-tunnel-reachable parameter is not specified:

       The local device advertises a labeled IPv4 route, regardless of whether a tunnel between the local and remote devices is reachable.

• Perform the following steps on each AGG ASBR and core ASBR:
  1. Run system-view

     The system view is displayed.

  2. Run interface interface-type interface-number

     The view of the interface connected to the peer ASBR is displayed.

  3. Run ip address ip-address { mask | mask-length }

     An IP address is assigned to the interface.

  4. Run mpls

     MPLS is enabled.

  5. Run quit

     Return to the system view.

  6. Run bgp { as-number-plain | as-number-dot }

     The BGP view is displayed.

  7. Run peer { ipv4-address | group-name } label-route-capability [ check-tunnel-reachable ]

     The capability of exchanging labeled IPv4 routes between BGP peers, including the peer ASBR and the devices in the local AS, is enabled.

     By default, the capability of exchanging labeled IPv4 routes is disabled.

     • If the label-route-capability is specified, a local device advertises an IPv4 unicast route to its peer if a tunnel between the local and remote devices is unreachable and advertises a labeled IPv4 route if the tunnel is reachable. This parameter helps prevent a data forwarding failure when an MP-EBGP peer relationship between the CSG and MASG is established but an LSP over the peer relationship fails to be established.
     • If the label-route-capability parameter is not specified, the local device advertises a labeled IPv4 route, regardless of whether a tunnel between the local and remote devices is unreachable.

  8. (Optional) Run supernet label-route advertise disable

     The ASBR is disabled from advertising BGP supernet labeled routes.

     By default, BGP supernet labeled routes can be preferentially selected and advertised.

     First disable the ASBR from advertising BGP supernet labeled routes, to advertise the loopback address route of a PE in the local AS to a PE in another AS. Next, run the network command on the ASBR to advertise the BGP route to the loopback address of the PE in the same AS.

  9. (Optional) Establishing an LDP LSP for the Labeled BGP Routes of the Public Network

     An IBGP peer relationship between the PE and the ASBR is unnecessary in this solution. An ASBR learns the labeled public BGP routes of the remote AS from the peer ASBR. Then these labeled public BGP routes are imported to IGP to trigger the establishment of an LDP LSP. A complete LDP LSP can then be established between the two PEs.

     1. Run quit

        The system view is displayed.

     2. Run mpls

        The MPLS view is displayed.

     3. Run lsp-trigger bgp-label-route [ ip-prefix ip-prefix-name ] [ not-only-host ]

        An LDP LSP is established for the labeled BGP routes of the public network that is filtered by the IP prefix list.

        By default, LDP does not allocate labels to labeled BGP routes on the public network.