3Com MSR 50 Series Configuration Manual page 1281

Introduction to Multicast Figure 369 shows an example of multicast over an MPLS VPNs network, which
VPN carries three independent multicast services - VPN instance A, VPN instance B, and
the public instance. A PE multicast device at the edge of the public network
supports multiple instances, equivalent to multiple independent multicast devices.
Each instance corresponds to a plane, and all these planes are isolated from one
another.
Figure 369 Multicast in multiple VPN instances
Site 1
VPN instance A
Public instance
Site 2
VPN instance B
With multicast VPN, as shown in
for example, sends a multicast stream to a multicast group, of all possible receivers
on the network for that group, only those belong to VPN A, namely in Site 1, Site
2 or Site 3, can receive the multicast stream. The stream is multicast in these sites
and in the public network.
The prerequisites for implementing multicast VPN are as follows:
1 The support for VPN instance based multicast within each site,
2 The support for public instance based multicast within the public network, and
3 PE devices that support multi-instance multicast:
Interfacing with sites and supporting VPN instance based multicast,
■
Interfacing with the public network and supporting public instance based
■
multicast, and
Supporting information exchange and data conversion between the public
■
instance and the VPN instances.
PE 1
MD A
PE 3
P
PE 1
PE 3
PE 1 MD B
PE 3
Figure 369, when a multicast source in VPN A,
Multicast VPN Overview
PE 2
Site 3
Site 5
PE 2
PIM
Site 4
PE 2
Site 6
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