PMSI

NG-MVPN extends the per-VRF tree with Provider Multicast Service Interfaces (PMSIs). A PMSI is a conceptual overlay on a provider network that enables a PE within a specific MVPN to multicast traffic to other PEs in that MVPN. These PMSIs are created by P-tunnels and signaled using mLDP.

SR Linux supports two PMSI types:

• Inclusive PMSI (I-PMSI / IPMSI): provides a broadcast domain for all PEs in the MVPN instance and serves as the default provider tunnel for all <S, G> traffic.
• Selective PMSI (S-PMSI / SPMSI): targets PEs that are interested in a specific <S, G>.

Each MVPN can use multiple mLDP P2MP trees, with one serving as the default for the Inclusive PMSI and one or more used for Selective PMSI. While the I-PMSI aggregates multiple flows, each P2MP mLDP S-PMSI LSP carries only one unique customer multicast flow, defined by the specific (C-S, C-G) pair (where C-S is customer source/sender and C-G is the customer multicast group/stream). Flows that cannot switch to S-PMSI remain on the I-PMSI.

P2MP LDP must be configured as an inclusive or selective provider tunnel per MVPN to dynamically initiate P2MP LSP to leaf PE nodes learned through NG-MVPN auto-discovery signaling.

P2MP LSP S-PMSI cannot be used for more than one (S,G) stream because the S-PMSI per MVPN limit is reached. P2MP LDP LSPs as inclusive or selective provider tunnels are available only with BGP NG-MVPN. P2MP LDP LSP is dynamically set up from leaf nodes after auto-discovery of leaf PE nodes participating in MVPN. Each LDP I-PMSI or S-PMSI LSP can be used with only one MVPN instance.