How many types of Auto-Discovery routes are defined for MCAST-VPN NLRI?

The BGP MCAST-VPN NLRI (Network Layer Reachability Information), as specified in the foundational standard RFC 6514, defines seven distinct route types. These routes are essential for the auto-discovery of PE routers participating in a specific Multicast VPN and for signaling customer multicast (C-multicast) routing information across the service provider's backbone.

The seven defined route types are:

1. Intra-AS I-PMSI A-D route

2. Inter-AS I-PMSI A-D route

3. S-PMSI A-D route

4. Leaf A-D route

5. Source Active A-D route

6. Shared Tree Join route

7. Source Tree Join route

Nokia's Service Router Operating System (SR OS) implements these seven route types for MVPN service delivery.

A. 3: This number is too low and does not align with the number of route types specified in the foundational RFC for MCAST-VPN.

B. 5: This count incorrectly omits the C-multicast join routes (Type 6 and 7), which are integral parts of the MCAST-VPN NLRI specification.

D. 9: This count includes route types from later standards (e.g., for BIER) that extend the original specification. The core MCAST-VPN standard defines seven types.

1. Rosen, E., et al. (February 2012). RFC 6514: BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs. IETF. Section 4, "BGP MCAST-VPN NLRI", and its subsections 4.1 through 4.7, which detail each of the seven route types.

2. Nokia. (October 2022). 7450 ESS, 7750 SR, 7950 XRS, and VSR Layer 3 Services Guide, Release 22.10.R1. Document Part Number: 3HE 18101 AAAC TQZZA, Edition 01. In the "MVPN" chapter, the section "MVPN Route Types" explicitly lists and describes the seven route types defined in RFC 6514.