Overlay multicast orchestration in software-defined wide area network

A first overlay network node of a software-defined network, comprising:

• a processing resource comprising one or more processors;
• and
• a non-transitory machine-readable medium storing instructions executable by the processing resource to:
• identify a host seeking to join a multicast stream;
• send state information of the first overlay network node to a multicast orchestrator;
• receive, at the first overlay network node from the multicast orchestrator, a partially populated multicast table comprising state information of overlay network nodes allowed to forward the multicast stream, wherein the partially populated multicast table comprises:
• a first entry identifying respective interfaces of a second overlay network node connected to a multicast source of the multicast stream and the first overlay network node, and
• a partially populated second entry for the first overlay network node, the partially populated second entry comprising a populated first interface field containing information of a first interface of the first overlay network node, and an empty second interface field that is without information of a second interface of the first overlay network node, the first interface connected to the second overlay network node, and the second interface connected to the host;
• update, at the first overlay network node, the partially populated second entry of the partially populated multicast table to form an updated multicast table by adding, to the empty second interface field, the information of the second interface of the first overlay network node;
• forward the multicast stream according to the updated multicast table.

A non-transitory machine-readable medium comprising instructions executable by a processing resource in a system for a software-defined wide area network (SD-WAN) to:

• receive, at a multicast orchestrator, state information from overlay network nodes of the SD-WAN;
• based on the state information, identify, from the overlay network nodes, a first overlay network node connected to a multicast source of a multicast stream and a second overlay network node connected to a host, wherein the second overlay network node comprises a first interface connected to the first overlay network node and a second interface connected to the host;
• based on the identifying, compute a partially populated multicast table representing a multicast tree comprising a path connecting the first overlay network node and the second overlay network node, the partially populated multicast table comprising:
• a first entry identifying respective interfaces of the first overlay network node connected to the multicast source and the second overlay network node, and
• a partially populated second entry comprising a populated first interface field identifying the first interface connected to the first overlay network node, and an empty second interface field that is without information identifying the second interface connected to the host;
• and
• distribute the partially populated multicast table to the first and second overlay network nodes to allow transmission of the multicast stream to the host;
• and
• update, at the second overlay network node, the partially populated second entry of the partially populated multicast table received at the second overlay network node by adding, to the empty second interface field, the information identifying the second interface connected to the host.