186
A flood-prune process (in PIM-DM) or a join process (in PIM-SSM) is initiated across the
public network to establish an SPT across the public network.
•
If the VPN network runs PIM-SM:
Hello packets are forwarded through MTI interfaces to establish PIM neighboring
relationships.
If the receivers and the VPN RP are in different sites, a join process is initiated across the
public network to establish an RPT.
If the multicast source and the VPN RP are in different sites, a registration process is
initiated across the public network to establish an SPT.
•
If the VPN network runs BIDIR-PIM:
Hello packets are forwarded through MTI interfaces to establish PIM neighboring
relationships.
If the receivers and the VPN RP are in different sites, a join process is initiated across the
public network to establish a receiver-side RPT.
If the multicast sources and the VPN RP are in different sites, join processes are initiated
across the public network to establish source-side RPTs.
NOTE:
PIM mode must be the same for all interfaces that belong to the same VPN, including those
interfaces that are bound with the VPN instance and the MTI interfaces on PE devices.
As shown in
•
PIM-SM is running in both the public network and the VPN network.
•
Receiver for the VPN multicast group G (225.1.1.1) in Site 2 is attached to CE 2.
•
CE 1 of Site 1 acts as the RP for group G (225.1.1.1).
•
The default-group address used to forward public network data is 239.1.1.1.
Figure 65 Transmission of multicast protocol packets
The multicast protocol packet is delivered as follows:
1.
Receiver sends an IGMP report to CE 2 to join the multicast group G. CE 2 creates a local state
entry (*, 225.1.1.1) and sends a join message to the VPN RP (CE 1).
Public instance BGP peers
MD
P
PE 1
PE 2
PE 3
BGP: 11.1.2.1/24
BGP: 11.1.3.1/24
Public instance join (11.1.2.1, 239.1.1.1)
BGP: 11.1.1.1/24
Default-group: 239.1.1.1
RP
CE 1
CE 2
Source
Receiver
G: 225.1.1.1
S: 192.1.1.1/24
VPN instance join (*, 225.1.1.1)
Site 1
Site 2
