Efficient multicast source roaming in an overlay network

A method, comprising:

• receiving, from a client device coupled to a port of a first network device in a distributed tunnel fabric comprising a plurality of network devices, a client join request to receive multicast traffic of a multicast group, wherein a respective pair of network devices of the distributed tunnel fabric are coupled to each other via a tunnel;
• sending, by the first network device, a network join request for the multicast group to a respective other network device of the distributed tunnel fabric;
• receiving, from a second network device of the distributed tunnel fabric, the multicast traffic of the multicast group via a first overlay tunnel between the first network device and the second network device, wherein a source of the multicast group is coupled to the second network device;
• and
• in response to the source roaming to a third network device of the distributed tunnel fabric, receiving, by the first network device from the third network device, the multicast traffic of the multicast group via a second overlay tunnel between the first network device and the third network device.

A non-transitory computer-readable storage medium storing instructions that when executed by at least one processing resource of a first network device in a distributed tunnel fabric cause the at least one processing resource to perform a method, the method comprising:

• receiving, by a first network device in a distributed tunnel fabric, a network join request to receive multicast traffic of a multicast group from a second network device in the distributed tunnel fabric, wherein a respective pair of network devices of the distributed tunnel fabric are coupled to each other via a tunnel;
• storing a multicast state for the multicast group in a data structure associated with a control plane of the first network device, wherein the multicast state indicates that the network join request is received via a first overlay tunnel between the first network device and the second network device;
• determining, by the first network device, whether a media access control (MAC) address of a source of the multicast group is learned from a local port of the first network device;
• and
• in response to learning the MAC address from the local port of the first network device:
• programming a multicast forwarding entry in forwarding hardware of the first network device based on the multicast state stored in the data structure;
• and
• forwarding, to the second network device, the multicast traffic received from the local port based on the multicast forwarding entry.