This feature provides a flexible multicast signaling solution to connect native IP multicast source and receivers that are running PIM multicast protocol via an intermediate MPLS (P2MP LDP LSP) network. It allows each native IP multicast flow to be connected via an intermediate P2MP LSP by dynamically mapping each PIM multicast flow to a P2MP LDP LSP.
It is not required to manually configure a mapping of (S,G) to a P2MP LSP on the edge node of MPLS network. A signaling method is defined that allows dynamic mapping of PIM signaling to P2MP LDP tree setup on the leaf node of P2MP LSP and also P2MP LDP signaling to be handed back to PIM on root node of P2MP LSP. Because of dynamic mapping of multicast IP flow to P2MP LSP, provisioning and maintenance overhead is eliminated as multicast distribution services are added and removed from the network.
P2MP LDP LSP signaling is initiated from node that receives PIM JOIN from a downstream node. The p2mp-ldp-tree-join command must be configured on PIM outgoing interface that received PIM JOIN to enable handover of multicast tree signaling from PIM to P2MP LDP LSP.
Leaf node of P2MP LDP LSP selects the upstream-hop as the root node of LDP FEC based on route table lookup. On the root node of P2MP LDP LSP, multicast tree signaling is handed back to PIM and propagated upstream as native-IP PIM JOIN.
Only PIM-SSM is supported with this feature. A single instance of P2MP LDP LSP is supported between the root and leaf nodes per multicast flow, that is, no stitching of dynamic trees.
If multiple criteria exist to set up a multicast flow, the following priorities are:
Multicast (statically provisioned) over P2MP LSP (RSVP-TE or LDP)
Dynamic multicast signaling over P2MP LDP
PIM native-IP multicast