Optimizing IP multicast delivery with use of local source nodes and the propagation of advertisements therefor

A network node comprising:

• one or more processors;
• a plurality of interfaces configured to connect in a network fabric of a plurality of network nodes;
• the one or more processors being configured to:
• identify that the network node is established as part of a multicast distribution tree of nodes that forward Internet Protocol (IP) multicast traffic originating from a source node to one or more host receiver devices of a multicast group, the IP multicast traffic comprising multicast data packets originating from the source node;
• in response to the identifying, propagating to one or more adjacent network nodes a message for advertising the network node as a candidate local source node at which to join the multicast group to receive via the network node the IP multicast traffic originating from the source node;
• and
• after the propagating of the message, receive from an adjacent network node a join request for joining a host receiver device to the multicast group and, in response, join the host receiver device in the multicast group at the network node for the host receiver device to receive via the network node the IP multicast traffic originating from the source node.

A method comprising:

• at an edge router configured to connect in a network fabric of interconnected network nodes,
• receiving a message which advertises a network node as a candidate local source node at which to join a multicast group to receive, via the network node, Internet Protocol (IP) multicast traffic originating from a source node, the network node being established as part of a multicast distribution tree of nodes that forward the IP multicast traffic which comprises multicast data packets originating from the source node to one or more host receiver devices of the multicast group;
• storing data associated with the message for advertising the network node as the candidate local source node, the data including a reachability metric associated with the candidate local source node;
• receiving from a host receiver device a join request for joining a host receiver device to the multicast group;
• selecting one of the source node or the candidate local source node based at least on the reachability metric associated with the candidate local source node;
• and
• causing the host receiver device to be joined in the multicast group at the selected one of the source node or the candidate local source node for the host receiver device to receive the IP multicast traffic of the multicast group.