Auto-derived RD in services with multiple BGP families

In a VPLS service, multiple BGP families and protocols can be enabled at the same time. When bgp-evpn is enabled, bgp-ad and bgp-mh are also supported. A single RD is used per service and not per BGP family or protocol.

The following rules apply:

• The VPLS RD is selected based on the following precedence:

  • Manual RD or automatic RD always take precedence when configured.

  • If no manual or automatic RD configuration, the RD is derived from the bgp-ad>vpls-id.

  • If manual RD, automatic RD, or VPLS ID are not configured, the RD is derived from the bgp-evpn>evi, except for bgp-mh and except when the EVI is greater than 65535. In these two cases, no EVI-derived RD is possible.

  • If manual RD, automatic RD, VPLS ID, or EVI is not configured, there is no RD and the service fails.

• The selected RD (see preceding rules) is displayed by the Oper Route Dist field of the show service id bgp command.

• The service supports dynamic RD changes. For example, the CLI allows the dynamic update of VPLS ID be , even if it is used to automatically derive the service RD for bgp-ad, bgp-vpls, or bgp-mh.

  Note: When the RD changes, the active routes for that VPLS are withdrawn and readvertised with the new RD.

• If one of the mechanisms to derive the RD for a specified service is removed from the configuration, the system selects a new RD based on the preceding rules. For example, if the VPLS ID is removed from the configuration, the routes are withdrawn, the new RD selected from the EVI, and the routes readvertised with the new RD.

  Note: This reconfiguration fails if the new RD already exists in a different VPLS or Epipe.

• Because the vpls-id takes precedence over the EVI when deriving the RD automatically, adding evpn to an existing bgp-ad service does not impact the existing RD. The latter is important to support bgp-ad to evpn migration.