Method to setup protocol independent multicast trees in the presence of unidirectional tunnels

摘要

Embodiments of the invention are directed to establishing a PIM tree to a source that is reachable over a unicast tunnel in a packet switched network. Advantageously, a Reverse Path Forwarding (RPF) Vector TLV to establish a PIM tree may be used in cases where there is an absence of source reachability in the core of a network.

主权项

1. A method of establishing a protocol independent multicast tree in a packet switched network, the method comprising:
at a first node in the network,
receiving a join message that indicates a source node of a multicast group;looking up a route to the source node;determining if the first node has an adjacency with a first next hop node along the route;forwarding the join message to the first next hop node responsive to the first node having an adjacency with the first next hop node; responsive to the first node not having an adjacency with the first next hop node:
performing a recursive next hop resolution of the first next hop node to find a second next hop on an alternate route to the source node through the first next hop node;responsive to not finding the alternate route:
dropping the join message; andresponsive to finding the alternate route and having an adjacency with the second next hop:
forwarding the join message to the second next hop node.