NG-MVPN: MVPN Type 5 to MSDP source active (SA) conversion/route propagation

Junos supports MVPN-Type-5 route to MSDP-SA conversion as defined in RFC draft-ietf-bess-mvpn-sa-to-msdp-00.txt. Previously, Junos only translation in the other direction, MSDP SA to MVPN Type 5. The ability to convert next-generation multicast virtual private network (MVPN) Type 5 routes to Multicast Source Discovery Protocol (MSDP) source active (SA) makes it possible to reduce the number of MSDP sessions running between VPN customer rendezvous points (C-RPs). For example, instead of having MSDP running among all C-RPs in a deployment, the C-RPs could instead run their MSDP sessions with a single PE router configured for multiple MSDP peers. The PE router, now acting as a C-RP device, would receive MVPN SA Type 5 routes from the RP-PE or source PE router, convert those routes to MSDP, and then advertise the MSDP routes to its MSDP peers. MVPN Type 5 SA routes are added to MVPN table and include a new Extended Community (EC), with the IPv4 address of the RP where the MVPN SA was generated. The Type 5 routes source and EC are additionally added to the MSDP table. Stale routes, including the EC, are removed via MSDP once the MVPN type 5 SA route is gone from the MVPN table. Enable MVPN to MSDP conversion at the [edit routing-instance name protocols mvpn mvpn-mode spt-only convert-sa-to-msdp] hierarchy level. You can verify whether MVPN type 5 routes are being correctly converted to MSDP SA by running the [show msdp source-active instance name] command.