Automation fallback to P2P LSPs for MLDP built multipoint-trees

A system comprising:

• first and second edge routers coupled to each other via a core router;
• and
• the core router configured to
• receive a stacked label multicast packet from the first edge router via a point-to-point label switched path (LSP), wherein
• the stacked label multicast packet comprises
• a multicast packet,
• a top label associated with the point-to-point LSP, and
• a bottom label associated with a point-to-multipoint LSP;
• select whether to pop or swap the top label from the stacked label multicast packet, wherein selecting whether to pop or swap comprises:
• popping the top label from the stacked label multicast packet to produce a labeled multicast packet, if the core router is the penultimate router of the point-to-point LSP from the first edge router to an ultimate router, or swapping the top label for a new top label to produce the labeled multicast packet, if the core router is not the penultimate router, and
• transmit the labeled multicast packet to the second edge router via the point-to-multipoint LSP.

An apparatus comprising:

• a core router comprising a first circuit, a second circuit, and a third circuit, wherein:
• the first circuit configured to receive a stacked label multicast packet from a first edge device via a point-to-point label switched path (LSP), wherein
• the stacked label multicast packet comprises
• a multicast packet,
• a top label associated with the point-to-point LSP, and
• a bottom label associated with a point-to-multipoint LSP;
• the second circuit configured to select whether to pop or swap the top label from the stacked label multicast packet, wherein selecting whether to pop or swap comprises:
• popping the top label from the stacked label multicast packet to produce a labeled multicast packet, if the core router is the penultimate router of the point-to-point LSP from the first edge router to an ultimate router, or swapping the top label for a new top label to produce the labeled multicast packet, if the core router is not the penultimate router;
• and
• the third circuit configured to transmit the labeled multicast packet to a second edge device via the point-to-multipoint LSP.