Configuring Inter-AS L2VPN Option C (with RRs Deployed)

In inter-AS LDP VPLS Option C, a device on an SP network only needs to establish a public tunnel with a PE in a different AS. ASBRs do not need to maintain inter-AS L2VPN information or reserve AC interfaces for inter-AS L2VPN PWs. As L2VPN information is exchanged only between PEs, this solution requires fewer resources and less configuration workload.

Procedure

Configure the capability to exchange labeled IPv4 routes.
- Configure each PE.
  1. Run system-view
    
    The system view is displayed.
  2. Run bgp as-number
    
    The BGP view is displayed.
  3. Run peer ipv4-address label-route-capability
    
    The PE is enabled to exchange labeled IPv4 routes with the ASBR within the local AS.
  4. Run commit
    The configuration is committed.
- Configure each ASBR.
  1. Run system-view
    
    The system view is displayed.
  2. Run interface interface-type interface-number
    
    The view of a local interface connected to the peer ASBR in another AS is displayed.
  3. Run ip address ip-address { mask | mask-length }
    
    An IP address is configured for the interface.
  4. Run mpls
    
    MPLS is enabled.
  5. Run quit
    
    Return to the system view.
  6. Run bgp as-number
    
    The BGP view is displayed.
  7. Run peer ipv4-address label-route-capability
    
    The capability to exchange labeled IPv4 routes with each PE in the local AS is enabled.
    
    In inter-AS Option C, an inter-AS VPN LSP must be established, and the public network routes advertised between PEs and ASBRs must carry MPLS labels.
    
    An EBGP peer relationship must be established between ASBRs in different ASs for them to exchange labeled IPv4 routes.
    
    The public network routes carrying MPLS labels are advertised through MP-BGP. According to relevant standard protocols, label mappings about routes can be piggybacked inside the BGP Update messages that are used to advertise these routes. This feature is implemented through an extended BGP attribute, which enables BGP peers to process labeled IPv4 routes.
  8. Run peer ipv4-address as-number peer-as
    
    A peer ASBR is specified as an EBGP peer.
  9. Run peer ipv4-address label-route-capability [ check-tunnel-reachable ]
    The local ASBR is enabled to exchange labeled IPv4 routes with the peer ASBR.
    If check-tunnel-reachable is configured, the ASBR advertises IPv4 unicast routes to the peer ASBR if the tunnel between them is unreachable and advertises labeled IPv4 routes if the tunnel is reachable. This parameter helps prevent traffic forwarding failures in scenarios where an MP-EBGP peer relationship is established between two PEs but an LSP segment over the peer session fails to be established.
    If check-tunnel-reachable is not configured, the ASBR advertises labeled IPv4 routes to the peer ASBR regardless of whether the tunnel between them is reachable.
  10. Run commit
    The configuration is committed.
Configure a route-policy on each ASBR to control label allocation.
Configure a route-policy to control MPLS label allocation for IPv4 routes on each ASBR. The ASBR only allocates labels to the routes that match filter rules defined in the policy.

By default, no MPLS labels are assigned to IPv4 routes.

Configure each ASBR.
1. Run system-view
  The system view is displayed.
2. Run route-policy policy-name1 permit node seq-number
  A route-policy is created to allow the ASBR to allocate MPLS labels to the matching IPv4 routes that are to be advertised to the local PE.
  
  After the route-policy is configured, if labeled IPv4 routes are to be advertised to the PE within the same AS, the ASBR re-allocates MPLS labels to the routes.
3. Run if-match mpls-label
  The ASBR is enabled to match labeled IPv4 routes against the route-policy.
4. Run apply mpls-label
  An action of allocating MPLS labels to the matching IPv4 routes is configured in the route-policy.
5. Run quit
  Return to the system view.
6. Run route-policy policy-name2 permit node seq-number
  A route-policy is created to allow the ASBR to allocate MPLS labels to the matching IPv4 routes that are to be advertised to the peer ASBR.
  
  For matching routes accepted from the PE in the same AS, the ASBR allocates MPLS labels to these routes before advertising them to the peer ASBR.
7. Run apply mpls-label
  An action of allocating MPLS labels to the matching IPv4 routes is configured in the route-policy.
8. Run quit
  Return to the system view.
9. Run system-view
  The system view is displayed.
10. Run bgp as-number
  The BGP view is displayed.
11. Run peer ipv4-address route-policy route-policy-name1 export
  The configured route-policy is applied to the routes to be advertised to the local PE.
12. Run peer ipv4-address route-policy route-policy-name2 export
  The configured route-policy is applied to the routes to be advertised to the peer ASBR.
13. Run commit
  The configuration is committed.
Configure the VPLS signaling capability for BGP peers.
- This configuration requires each ASBR to advertise the local PEs' loopback interface addresses used for BGP sessions to the peer ASBR and then to PEs in the same AS as the peer ASBR. Configure each ASBR.
  1. Run system-view
    
    The system view is displayed.
  2. Run bgp as-number
    
    The BGP view is displayed.
  3. Run network ip-address [ mask | mask-length ] [ route-policy route-policy-name ]
    
    A loopback interface address used for BGP session creation on the PEs are advertised in the AS.
  4. Run commit
    The configuration is committed.
- Configure the VPLS signaling capability between the ASBR and the local RR and between the ASBR and the peer ASBR. Configure each ASBR.
  1. Run system-view
    
    The system view is displayed.
  2. Run bgp as-number
    
    The BGP view is displayed.
  3. Run peer ipv4-address as-number peer-as
    
    A peer is specified.
  4. Enable the VPLS signaling capability.
    Run l2vpn-ad-family
    
    The L2VPN-AD address family view is displayed.
    
    Run peer ipv4-address enable
    
    The device is enabled to exchange routing information with a specified BGP peer is enabled.
    
    Run signaling vpls or peer ipv4-address signaling vpls
    
    The VPLS signaling capability is enabled.
  5. Run peer ipv4-address next-hop-invariable
    
    The device is disabled from changing the next hop addresses in routes before sending routes to a specified peer. Repeat running this command with the ipv4-address value set to the IPv4 address of each of the local RR and peer ASBR.
- Configure each PE.
  1. Run system-view
    
    The system view is displayed.
  2. Run bgp as-number
    
    The BGP view is displayed.
  3. Run peer ipv4-address as-number peer-as
    
    The RR within the local AS is specified as an IBGP peer of the PE.
  4. Enable the VPLS signaling capability.
    Run l2vpn-ad-family
    
    The L2VPN-AD address family view is displayed.
    
    Run peer ipv4-address enable
    
    The PE is enabled to exchange routing information with a specified BGP peer.
    
    Run signaling vpls or peer ipv4-address signaling vpls
    
    The VPLS signaling capability is enabled.
- Configure each RR.
  1. Run system-view
    
    The system view is displayed.
  2. Run bgp as-number
    
    The BGP view is displayed.
  3. Run peer ipv4-address as-number peer-as
    
    An IBGP peer is specified. Repeat running this command with the ipv4-address value set to the IPv4 address of each of the local PE and ASBR.
  4. Enable the VPLS signaling capability.
    Run l2vpn-ad-family
    
    The L2VPN-AD address family view is displayed.
    
    Run peer ipv4-address enable
    
    The device is enabled to exchange routing information with a specified PE or ASBR within the local AS.
    
    Run signaling vpls or peer ipv4-address signaling vpls
    
    The VPLS signaling capability is enabled.
    
    Run peer ipv4-address reflect-client
    The device is configured as an RR, and its peer is configured as the client of the RR.
Configure BGP VPLS on each PE. For configuration details, see Configuring BGP VPLS.