Protocol independent multicast (PIM) across transport network

A method comprising:

• receiving, by a first network device and from a multicast sender device connected to the first network device via a Layer-2 (L2) network, a multicast packet for a multicast group associated with a multicast service;
• generating, by the first network device and based at least in part on the multicast packet, a unicast Layer-3 (L3) packet comprising:
• a header that specifies a source address as an address of a virtual loopback interface of a second network device to which the unicast L3 packet is destined, wherein the virtual loopback interface identifies a PIM service for the multicast service, the PIM service being one of a plurality of PIM services between the first network device and the second network device, and the virtual loopback interface being one of a plurality of virtual lookback interfaces of the second network device, wherein each virtual loopback interface of the plurality of virtual loopback interfaces identifies a different PIM service of the plurality of PIM services;
• and
• a payload comprising a Protocol Independent Multicast (PIM) Register request destined to a Rendezvous Point (RP) device for the multicast service to register the first network device as a multicast source for the multicast group, wherein the multicast sender device, the first network device, the second network device, and the RP device are distinct from one another;
• and
• forwarding, by the first network device, the unicast L3 packet across an L3 transport network to the second network device.

Non-transitory, computer-readable media comprising instructions that, when executed, are configured to cause processing circuitry of a first network device to:

• receive, from a multicast sender device connected to the first network device via a Layer-2 (L2) network, a multicast packet for a multicast group associated with a multicast service;
• generate, based at least in part on the multicast packet, a unicast Layer-3 (L3) packet comprising:
• a header that specifies a source address as an address of a virtual loopback interface of a second network device to which the unicast L3 packet is destined, wherein the virtual loopback interface identifies a PIM service for the multicast service, the PIM service being one of a plurality of PIM services between the first network device and the second network device, and the virtual loopback interface being one of a plurality of virtual lookback interfaces of the second network device, wherein each virtual loopback interface of the plurality of virtual loopback interfaces identifies a different PIM service of the plurality of PIM services;
• and
• a payload comprising a Protocol Independent Multicast (PIM) Register request destined to a Rendezvous Point (RP) device for the multicast service to register the first network device as a multicast source for the multicast group, wherein the multicast sender device, the first network device, the second network device, and the RP device are distinct from one another;
• and
• forward the unicast L3 packet across an L3 transport network to the second network device.