Grafts To A Multicast Tree; Pim Dm Versions - Dell PowerConnect B-RX Configuration Manual

23
PIM dense
FIGURE 91

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.

PIM DM versions

The BigIron RX supports PIM DM V1 and V2. The default is V2. You can specify the version on an
individual interface basis.
592
Pruning leaf nodes from a multicast tree
229.225.0.1
Group Group
Member
Member
R2
Prune Message
sent to upstream router (R4)
R5
Leaf Node
(No Group Members)
(No Group Members)
Video Conferencing
Server
(207.95.5.1, 229.225.0.1)
(Source, Group)
R1
R4
...
Intermediate Node
229.225.0.1
Group Group Group
Member Member
Member
...
R3
R6
...
Group Group Group
Member Member Member
229.225.0.1
BigIron RX Series Configuration Guide
53-1001986-01