Enabling BGP Peers to Exchange Labeled IPv4 Routes

In the seamless MPLS networking, before an E2E BGP LSP is established, BGP peers must be able to exchange labeled IPv4 routes with each other.

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 ability to exchange labeled IPv4 routes between devices in the local AS is enabled.
  - If the check-tunnel-reachable is configured, 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 check-tunnel-reachable parameter is not configured, the local device advertises a labeled IPv4 route, regardless of whether a tunnel between the local and remote devices is unreachable.
4. Run commit
  The configuration is committed.
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 ability to exchange labeled IPv4 routes between BGP peers, including the peer ASBR and the devices in the local AS, is enabled.
  - If the check-tunnel-reachable is configured, 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 check-tunnel-reachable parameter is not configured, the local device advertises a labeled IPv4 route, regardless of whether a tunnel between the local and remote devices is unreachable.
8. Run commit
  The configuration is committed.