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

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PIM Dense
FIGURE 121
sent to upstream router (R4)

Grafts to a multicast Tree

A PIM switch restores pruned branches to a multicast tree by sending graft messages towards the
upstream switch. Graft messages start at the leaf node and travel up the tree, first sending the
message to its neighbor upstream switch.
In the example above, if a new 229.255.0.1 group member joins on switch S6, which was
previously pruned, a graft is sent upstream to S4. Since the forwarding state for this entry is in a
prune state, S4 sends a graft to S1. Once S4 has joined the tree, S4 and S6 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

Dell PowerConnect devices support PIM DM V1 and V2. The default is V2. You can specify the
version on an individual interface basis.
The primary difference between PIM DM V1 and V2 is the methods the protocols use for
messaging:
•
736
Pruning leaf nodes from a multicast tree
229.225.0.1
Group Group
Member Member
R2
Prune Message
R5
Leaf Node
(No Group Members)
Intermediate Node
(No Group Members)
PIM DM V1 – uses the Internet Group Management Protocol (IGMP) to send messages
Video Conferencing
Server
(207.95.5.1, 229.225.0.1)
(Source, Group)
229.225.0.1
Group
Member
R1
R3
R4
R6
...
Group Group
Member Member
229.225.0.1
PowerConnect B-Series FCX Configuration Guide
Group Group
Member
Member
...
...
Group
Member
53-1002266-01