Foundry Networks Switch and Router User Manual

Foundry Switch and Router Installation and Configuration Guide
18 - 6 December 2000
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.
Console
NetIron
Console
NetIron
Console
NetIron
Console
NetIron
Console
NetIron
Console
NetIron
Group
Member
Group
Member
Leaf Node
(No Group Members)
R5
R3
R4
R6
R1
R2
Leaf Node
Leaf Node
Video Conferencing
Server
(207.95.5.1, 229.225.0.1)
(Source, Group)
...
Group
Member
Group
Member
Group
Member
...
Group
Member
Group
Member
Group
Member
...
Prune Message
sent to upstream router (R4)
Interrmediate Node
(No Group Members)
229.225.0.1
229.225.0.1 229.225.0.1

Foundry Networks Switch and Router Specifications

General

Brand	Foundry Networks
Model	Switch and Router
Category	Switch
Language	English