251
Share-MDT establishment in a PIM-DM network
Figure 75 Share-MDT establishment in a PIM-DM network
As shown in
, PIM-DM is enabled in the network and all the PE devices support VPN
instance A. The process of establishing a share-MDT is as follows:
The public network on PE 1 initiates a flood-prune process in the entire public network, with the BGP
interface address (the interface address used to establish the BGP peer) as the multicast source
address and the share-group address as the multicast group address. All the other PE devices that
are running VPN instance A are group members, so that a (11.1.1.1, 239.1.1.1) state entry is created
on each device along the path in the public network. This forms an SPT with PE 1 as the root, and PE
2 and PE 3 as leaves.
At the same time, PE 2 and PE 3 separately initiate a similar flood-prune process. Finally, three
independent SPTs are established in the MD. In the PIM-DM network, these independent SPTs
constitute a share-MDT.
Share-MDT establishment in a PIM-SM network
Figure 76 Share-MDT establishment in a PIM-SM network
Public network BGP peers
MD
P
PE 3
PE 2
PE 1
BGP: 11.1.2.1/24
BGP: 11.1.1.1/24
SPT (11.1.1.1, 239.1.1.1)
SPT (11.1.2.1, 239.1.1.1)
SPT (11.1.3.1, 239.1.1.1)
BGP: 11.1.3.1/24
Share-Group: 239.1.1.1
Public instance BGP peers
RPT (*, 239.1.1.1)
MD
P
RP
PE 3
PE 2
PE 1
BGP: 11.1.2.1/24
BGP: 11.1.1.1/24
SPT (11.1.1.1, 239.1.1.1)
SPT (11.1.2.1, 239.1.1.1)
SPT (11.1.3.1, 239.1.1.1)
BGP: 11.1.3.1/24
Share-Group: 239.1.1.1