After exploring Internet Multicast over MPLS, let’s see Multicast VPN (MVPN) over MPLS. The three implemented models in growing scalability order, are:
VRF In-Band mLDP, only implemented in IOS XR. In the terms of Table 4-1, this model is S2, A2, C2, E3, T2, Y3. It is nearly identical to the one discussed for Internet Multicast in Chapter 4, but it also encodes VPN-specific information (the RD of the S unicast route) in the LDP opaque value.
BGP Multicast VPN, formerly known as Next-Generation MVPN or NG-MVPN. It is implemented by both Junos and IOS XR. In the terms of Table 4-1, this model is S2, A3, C3, [E1, E2, E3], [T0, T1, T2, T3, T4], [Y1, Y2, Y3, Y4]. Not all the combinations make sense and/or are supported, though.
As of this writing, the only interoperable solution is BGP MVPN. Fortunately, it is the most flexible and scalable flavor of them all. Table 4-1 lists the different C-Multicast Architectures: Out-of-band (A3) is more scalable than Hop-by-Hop Inter-PE (A2), which in turn is more scalable than Direct Inter-PE (A1). The only implemented solution that is compatible with the A3 model is precisely BGP MVPN.
MVPN is a multidimensional universe, whose richest galaxy is BGP MVPN. Its Out-of-Band signaling approach, which decouples service from transport, makes BGP MVPN flavors and use cases quite extensive. ...