Redundancy for inter-AS L2VPN service with optimal forwarding

An apparatus, comprising:

• one or more network interfaces to communicate within a control-plane media access control (MAC) learning (CPML) network as a particular autonomous system border router (ASBR), and to communicate with a respective ASBR of a data-plane MAC learning (DPML) network;
• a processor coupled to the network interfaces and adapted to execute one or more processes;
• and
• a memory configured to store a process executable by the processor, the process when executed operable to:
• discover one or more other ASBRs in the CPML network, wherein the one or more other ASBRs are interconnected with respective ASBRs of the DPML network;
• calculate one or more internal shortest path first (SPF) trees rooted respectively at each of the other ASBRs in the CPML network;
• receive a MAC advertisement route for a given MAC address with a given next-hop Internet Protocol (IP) address;
• determine a distance from the particular ASBR and from each other ASBR in the CPML network to the given IP address based on the internal SPF trees;
• and
• in response to the distance from the particular ASBR being shorter than the distance from each other ASBR, designate the particular ASBR as a designated forwarder (DF) for traffic sourced from the given MAC address.

A tangible, non-transitory, computer-readable media having software encoded thereon, the software when executed by a processor operable to:

• discover, for a particular autonomous system border router (ASBR) in a control-plane media access control (MAC) learning (CPML) network, one or more other ASBRs in the CPML network, wherein the particular ASBR and one or more other ASBRs are interconnected with respective ASBRs of a data-plane MAC learning (DPML) network;
• calculate one or more internal shortest path first (SPF) trees rooted respectively at each of the other ASBRs in the CPML network;
• receive a MAC advertisement route for a given MAC address with a given next-hop Internet Protocol (IP) address;
• determine a distance from the particular ASBR and from each other ASBR in the CPML network to the given IP address based on the internal SPF trees;
• and
• in response to the distance from the particular ASBR being shorter than the distance from each other ASBR, designate the particular ASBR as a designated forwarder (DF) for traffic sourced from the given MAC address.