HP A6600 Configuration Manual page 235

share-MDT, and then decapsulated on the remote PE device to go into the normal protocol procedure.
Finally a distribution tree is established across the public network.
The following lists how multicast protocol packets are forwarded in the following circumstances:
• If the VPN network runs PIM-DM or PIM-SSM:
Hello packets are forwarded among MTI interfaces to establish PIM neighboring relationships.
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 among 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.
All interfaces that belong to the same VPN, including those interfaces with VPN instance bindings and the
MTI on PE devices, must run the same PIM mode.
The following example explains how multicast protocol packets are delivered based on the share-MDT
when PIM-SM is running in both the public network and the VPN network, with receivers and the VPN RP
located in different sites.
As shown in Figure 69, 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, and CE 1 of Site 1 acts as the RP for
group G (225.1.1.1); the share-group address used to forward public network data is 239.1.1.1.
Figure 69 Transmission of multicast protocol packets
Source
RP
CE 1
Site 1
S: 192.1.1.1/24
G: 225.1.1.1
Share-Group: 239.1.1.1
The work process of multicast protocol packets is as follows:
Receiver sends an IGMP membership report for multicast group G to CE 2. CE 2 creates a local (*,
•
225.1.1.1) state entry and sends a join message to the VPN RP (CE 1).
After receiving the join message from CE 2, the VPN instance on PE 2 creates a (*, 225.1.1.1) state
•
entry with the upstream interface being the MTI, and then PE 2 processes the join message. Now,
the VPN instance on PE 2 considers that the join message has been sent out the MTI.
BGP: 11.1.3.1/24
PE 3
P
PE 1
MD
BGP: 11.1.1.1/24
224
CE 2
PE 2
BGP: 11.1.2.1/24
Public instance BGP peers
VPN instance join (*, 225.1.1.1)
Public instance join (11.1.2.1, 239.1.1.1)
Receiver
Site 2