Foundry Networks Switch and Router Installation And Configuration Manual page 667

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 18.6 Pruning leaf nodes from a multicast tree
Grafts to a Multicast Tree
A DVMRP 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 had been pruned previously,
a graft will be 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, it along with R6 will once again receive multicast packets.
You do not need to perform any configuration to maintain the multicast delivery tree. The prune and graft
messages automatically maintain the tree.
December 2000
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
Configuring IP Multicast Protocols
229.225.0.1
Group Group Group
Member Member Member
...
NetIron
R3
NetIron
R6
Leaf Node
...
Group Group
Member Member
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