Programming multicast forwarding entries in an overlay network

A non-transitory computer-readable storage medium storing instructions to:

• receive, by a first network device via a first tunnel in a first overlay network, a notification message indicating that a host reachable via a second network device joined a multicast group, wherein the first tunnel is between the first and second network devices;
• determine whether the first network device is a distributor of multicast traffic in the first overlay network;
• and
• in response to determining that the first network device is the distributor:
• program forwarding hardware of the first network device with a first multicast forwarding entry for the multicast group based on the notification message;
• receive, by the first network device, multicast traffic of the multicast group over a second tunnel from a third network device;
• and
• forward the multicast traffic over the first tunnel to the second network device based on the first multicast forwarding entry.

A computer system, comprising:

• at least one processing resource;
• forwarding hardware;
• and
• a non-transitory computer-readable storage medium storing instructions that when executed by the processing resource cause the computer system to:
• receive, via a first tunnel in a first overlay network, a notification message indicating that a host reachable via a first network device joined a multicast group, wherein the first tunnel is between the computer system and the first network device;
• determine whether the computer system is a distributor of multicast traffic in the first overlay network;
• and
• in response to determining that the computer system is the distributor:
• program the forwarding hardware with a first multicast forwarding entry for the multicast group based on the notification message;
• receive multicast traffic of the multicast group over a second tunnel from a second network device;
• and
• forward the multicast traffic over the first tunnel to the first network device based on the first multicast forwarding entry.