H3C Technologies H3C S10500 Series Switches - Manual (Page 28)

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and an instance can reside on different PE devices. On a PE device, the instance for the public
network is called the public network instance, and those for VPNs are called VPN instances.
Multi-instance application in multicast
With multi-instance multicast enabled, a PE device can do the following operations:
• Maintain a set of independent multicast forwarding mechanisms for each instance, including the
multicast protocols, PIM neighbor list, and multicast routing table. Each instance forwards multicast
data based on its own forwarding table or routing table.
• Guarantee the isolation between different VPN instances.
• Implement information exchange and data conversion between the public network and VPN
instances.
Multicast VPN implements multicast on MPLS L3VPN networks. As shown in Figure 10 , when a multicast
source in VPN A sends a multicast stream to a multicast group, of all possible receivers on the network
for that group, only those that belong to VPN A can receive the multicast stream. The multicast data is
multicast both in VPN A and in the public network.