Grafts To A Multicast Tree - Foundry Networks Switch and Router Installation And Configuration Manual

Foundry Switch and Router Installation and Configuration Guide
229.225.0.1
Group
Member
NetIron
Console
Leaf Node
Prune Message
sent to upstream router (R4)
NetIron
Console
Leaf Node
(No Group Members)
Figure 18.2 Pruning leaf nodes from a multicast tree

Grafts to a Multicast Tree

A PIM router restores pruned branches to a multicast tree by sending graft messages towards the upstream
router. Graft messages start at the leaf node and travel up the tree, first sending the message to its neighbor
upstream router.
In the example above, if a new 229.255.0.1 group member joins on router R6, which was previously pruned, a
graft is sent upstream to R4. Since the forwarding state for this entry is in a prune state, R4 sends a graft to R1.
Once R4 has joined the tree, R4 along with R6 once again receive multicast packets.
Prune and graft messages are continuously used to maintain the multicast delivery tree. No configuration is
required on your part.
18 - 6
Group
Member
NetIron
Console
R2
NetIron
Console
R5
Interrmediate Node
(No Group Members)
Video Conferencing
Server
(207.95.5.1, 229.225.0.1)
(Source, Group)
R1
Console
R4
...
Console
Group
Member
229.225.0.1
229.225.0.1
Group Group Group
Member Member Member
...
NetIron
R3
NetIron
R6
Leaf Node
...
Group Group
Member Member
December 2000