4000 Router Series IP Multicast Configuration Guide

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PIM neighboring relationships in MD-VPN

Figure 59 PIM neighboring relationships in MD-VPN

PIM neighboring relationships are established between two or more directly interconnected devices on

the same subnet. As shown in Figure 59,

the following types of PIM neighboring relationships exist in

MD-VPN:

• PE-P PIM neighboring relationship—Established between the public network interface on a PE

device and the peer interface on the P device over the link.

• PE-PE PIM neighboring relationship—Established between PE devices that are in the same VPN

instance after they receive the PIM hello packets.

• PE-CE PIM neighboring relationship—Established between a PE interface that is bound with the

VPN instance and the peer interface on the CE device over the link.

Protocols and standards

RFC 6037, Cisco Systems' Solution for Multicast in BGP/MPLS IP VPNs

How MD-VPN works

This section describes how the MD-VPN technology is implemented, including the default-MDT

construction, multicast traffic delivery based on the default-MDT, and inter-AS MD-VPN implementation.

The VPN multicast data transmission on the public network is transparent to this VPN instance. The MTIs

at the local PE device and the remote PE device form a channel for the seamless transmission of VPN data

over the public network. All that is known to the VPN instance is that the VPN data is sent out of the MTI

and then the remote site can receive the data through the MTI. Actually, the multicast data transmission

over the public network, or transmission over MDT, is very complicated.