Bidirectional Rpt Building - HP A6600 Configuration Manual

In the case of a tie, the router with the route with the lowest metric wins the DF election.
3.
In the case of a tie in the metric, the router with the highest IP address wins.
4.

Bidirectional RPT building

A bidirectional RPT comprises a receiver-side RPT and a source-side RPT. The receiver-side RPT is rooted
at the RP and takes the routers directly connected to the receivers as leaves. The source-side RPT is also
rooted at the RP but takes the routers directly connected to the sources as leaves. The processes for
building these two parts are different.
Figure 39 RPT building at the receiver side
Receiver
Host A
Source
Server A
Join message
Receiver-side RPT
Multicast packets
As shown in Figure
PIM-SM:
When a receiver joins multicast group G, it uses an IGMP message to inform the directly connected
1.
router.
After getting the receiver information, the router sends a join message, which is forwarded hop by
2.
hop to the RP of the multicast group.
The routers along the path from the receiver's directly connected router to the RP form an RPT
3.
branch, and each router on this branch adds a (*, G) entry to its forwarding table. The * means any
multicast source.
When a receiver is no longer interested in the multicast data addressed to multicast group G, the directly
connected router sends a prune message, which goes hop by hop along the reverse direction of the RPT
to the RP. After receiving the prune message, each upstream node deletes the interface connected to the
downstream node from the outgoing interface list and checks whether it has receivers in that multicast
group. If not, the router continues to forward the prune message to its upstream router.
RP
39, the process for building a receiver-side RPT is similar to that for building an RPT in
Source
Host C
102
Server B
Receiver
Host B
Receiver