Segment Routing MPLS Point To Multipoint Path

A method implemented by a transit node in a network on a segment routing point to multipoint (SR P2MP) path, the method comprising:

• receiving a packet in Multiprotocol Label Switching (MPLS) format, the packet comprising an upstream segment list describing one or more sub-trees of the SR P2MP path;
• determining, based on the upstream segment list, a downstream segment list describing a sub-tree for a downstream interface of the transit node included in the SR P2MP path, the downstream segment list comprising a list of multicast segment identifiers (SIDs) each comprising a multicast adjacency label;
• replacing the upstream segment list associated with the packet with the downstream segment list;
• and
• transmitting the packet from the downstream interface along the SR P2MP path.

A non-transitory computer readable medium comprising a computer program product for use by a first node in a network, the computer program product comprising computer executable instructions stored on the non-transitory computer readable medium such that when executed by a processor cause the first node to:

• receive a packet;
• push onto the packet a segment list describing a segment routing point to multipoint (SR P2MP) path as a list of multicast segment identifiers (SIDs) each comprising a multicast adjacency label;
• and
• transmit the packet from a downstream interface along the SR P2MP path.