Configuring Inter-AS BGP VPLS Option C

In inter-AS BGP VPLS Option C, ASBRs do not need to maintain VPLS information or reserve interfaces for inter-AS PWs. As BGP VPLS information is exchanged directly between PEs, this solution requires few resources and is easy to deploy.

Procedure

  1. Enable the capability to exchange labeled IPv4 routes.

    • Perform the following steps on 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 capability to exchange labeled IPv4 routes with the local ASBR is enabled.

      4. Run commit

        The configuration is committed.

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

        The system view is displayed.

      2. Run interface interface-type interface-number

        The interface view is displayed.

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

        An IP address is specified 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 local PEs is enabled.

        In inter-AS BGP VPLS Option C, an inter-AS LSP must be established, and the public network routes advertised between PEs and ASBRs carry MPLS labels.

        An MP-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 standards, 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 as-number

        The peer ASBR is configured as an MP-EBGP peer.

      9. Run peer ipv4-address label-route-capability [ check-tunnel-reachable ]

        The capability to exchange labeled IPv4 routes with the peer ASBR is enabled.

        • 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 label-route-capability 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.

  2. Configure routing policies on each ASBR, so that an ASBR reallocates MPLS labels to the labeled IPv4 routes to be advertised to the local PE and allocates MPLS labels to the routes to be advertised to the peer ASBR.

    ASBRs allocate MPLS labels to IPv4 routes based on the configured routing policies.

    Perform the following steps on each ASBR:

    1. Run system-view

      The system view is displayed.

    2. Run route-policy policy-name1 permit node seq-number

      A routing policy applicable to the local PE is created.

    3. Run if-match mpls-label

      Filtering out labeled IPv4 routes is configured as a matching rule for the routing policy.

    4. Run apply mpls-label

      Allocating MPLS labels to IPv4 routes is configured as an action for the routing policy.

    5. Run quit

      Return to the system view.

    6. Run route-policy policy-name2 permit node seq-number

      A routing policy applicable to the peer ASBR is created.

    7. Run apply mpls-label

      Allocating MPLS labels to IPv4 routes is configured as an action for the routing 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 routing policy applicable to the local PE is applied.

    12. Run peer ipv4-address route-policy route-policy-name2 export

      The routing policy applicable to the peer ASBR is applied.

    13. Run commit

      The configuration is committed.

  3. Establish an MP-EBGP peer relationship between PEs. 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.

    • Perform the following steps on 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 ]

        The capability to advertise the local PEs' loopback interface addresses used for BGP sessions to the peer ASBR is enabled.

      4. Run commit

        The configuration is committed.

    • Perform the following steps on 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 as-number

        The peer PE is specified as an MP-EBGP peer.

      4. Run peer ipv4-address ebgp-max-hop [ hop-count ]

        The maximum number of hops allowed for an MP-EBGP peer session is specified.

        When establishing an MP-EBGP peer relationship between two indirectly connected PEs in different ASs, specify the maximum number of hops allowed for the MP-EBGP peer session and ensure that the two PEs are reachable to each other.

      5. Enable the VPLS signaling capability.
        1. Run l2vpn-ad-family

          The L2VPN-AD address family view is displayed.

        2. Run peer ipv4-address enable

          The capability to exchange route information with BGP peers is enabled.

        3. Run signaling vpls or peer ipv4-address signaling vpls

          The VPLS signaling capability is enabled.

        4. (Optional) Run signaling vpls-ad disable

          The BGP AD signaling capability is disabled.

          The BGP AD signaling capability is automatically enabled after you run the peer ipv4-address enable command in the L2VPN-AD address family view. When configuring BGP VPLS, you can disable the BGP AD signaling capability.

      6. (Optional) Run peer ipv4-address next-hop-invariable

        The PE is configured to advertise labeled IPv4 routes to MP-EBGP peers without changing the next hops of these routes.

        This step is used in scenarios where RRs are used to advertise L2VPN label blocks. The next hop cannot be changed when label blocks are exchanged between RRs.

    • Run commit

      The configuration is committed.

  4. Configure BGP VPLS on each PE. For configuration details, see Configuring BGP VPLS.
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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