HP MSR2003 Configuration Manual page 190

multicast packets on the local PE device, and transmitted along the default-MDT. When the VPN multicast
packets arrive at the remote PE device, they are decapsulated and transmitted in that VPN site.
VPN multicast data packets are forwarded across the public network differently in the following
circumstances:
If PIM-DM or PIM-SSM is running in the VPN, the multicast source forwards multicast data packets
•
to the receivers along the VPN SPT across the public network.
• When PIM-SM is running in the VPN:
Before the RPT-to-SPT switchover, if the multicast source and the VPN RP are in different sites, the
VPN multicast data packets travel to the VPN RP along the VPN SPT across the public network.
If the VPN RP and the receivers are in different sites, the VPN multicast data packets travel to the
receivers along the VPN RPT over the public network.
After the RPT-to-SPT switchover, if the multicast source and the receivers are in different sites, the
VPN multicast data packets travel to the receivers along the VPN SPT across the public network.
• When BIDIR-PIM is running in the VPN, if the multicast source and the VPN RP are in different sites,
the multicast data travels to the VPN RP across the public network along the source-side RPT. If the
VPN RP and the receivers are in different sites, the multicast data travels to the receivers across the
public network along the receiver-side RPT.
For more information about RPT-to-SPT switchover, see "Configuring PIM."
The following example explains how multicast data packets are delivered based on the default-MDT
when PIM-DM is running in both the public network and the VPN network.
As shown in Figure 63:
• PIM-DM is running in both the public network and the VPN sites.
Receiver of the VPN multicast group G (225.1.1.1) in Site 2 is attached to CE 2.
•
Source in Site 1 sends multicast data to multicast group (G).
•
The default-group address used to forward public network multicast data is 239.1.1.1.
•
Figure 63 Multicast data packet delivery
A VPN multicast data packet is delivered across the public network as follows:
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