Foundry Networks FESX User Manual

Foundry Configuration Guide for the FESX, FSX, and FWSX
19 - 8 © Foundry Networks, Inc. December 2005
Figure 19.2 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.
PIM DM Versions
Foundry 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:
• PIM DM V1 – uses the Internet Group Management Protocol (IGMP) to send messages
• PIM DM V2 – sends messages to the multicast address 224.0.0.13 (ALL-PIM-ROUTERS) with protocol
number 103
The CLI commands for configuring and managing PIM DM are the same for V1 and V2. The only difference is the
command you use to enable the protocol on an interface.
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 FESX Specifications

General

Brand	Foundry Networks
Model	FESX
Category	Switch
Language	English