Layer 3 (L3) best route selection rule for shortest path bridging multicast (SPBM) networks

A non-transitory computer readable storage medium having computer readable code thereon for providing a best route selection rule, the medium including instructions in which a computer system performs operations comprising:

• determining, at a first edge router, that a second edge router in a network advertises a first Backbone Media Access Control (BMAC) address and a shared BMAC address, where said shared BMAC address is shared by a cluster of edge routers;
• determining, at said first edge router, that a third edge router in a network advertises a second Backbone Media Access Control (BMAC) address and said shared BMAC address;
• using said shared BMAC address in a routing table for a Layer 3 (L3) next hop for a route;
• pointing, using a first record separate from the routing table, said shared BMAC address to said first BMAC address associated with the second edge router for said L3 next hop for said route;
• detecting that said second edge router has failed;
• and
• re-pointing said shared BMAC address to said third edge router in said cluster of edge routers by updating said first record to point said shared BMAC address to said second BMAC address associated with the third edge router, without modifying said route in said routing table, such that a time to recover connectivity is independent of a number of L3 routes in said routing table.

A computer system comprising:

• a memory;
• a processor;
• a communications interface;
• an interconnection mechanism coupling the memory, the processor and the communications interface;
• and
• wherein the memory is encoded with an application providing a best route selection rule, that when performed on the processor, provides a process for processing information, the process causing the computer system to perform the operations of:
• determining, at a first edge router, that a second edge router in a network advertises a first Backbone Media Access Control (BMAC) address and a shared BMAC address, where said shared BMAC address is shared by a cluster of edge routers;
• determining, at said first edge router, that a third edge router in a network advertises a second Backbone Media Access Control (BMAC) address and said shared BMAC address;
• using said shared BMAC address in a routing table for a Layer 3 (L3) next hop for a route;
• pointing, using a first record separate from the routing table, said shared BMAC address to said first BMAC address associated with the second edge router for said L3 next hop for said route;
• detecting that said second edge router has failed;
• and
• re-pointing said shared BMAC address to said third edge router in said cluster of edge routers by updating said first record to point said shared BMAC address to said second BMAC address associated with the third edge router, without modifying said route in said routing table, such that a time to recover connectivity is independent of a number of L3 routes in said routing table.