Alcatel Carrier Internetworking Solutions 6648 - Manual (Page 280)

Join/Prune Troubleshooting PIM-SM
page 16-18 OmniSwitch Troubleshooting Guide September 2005
Join/Prune
Join/Prune messages are sent by the DR to join or prune a branch off the multicast distribution tree in
order to receive multicast group on a specific LAN segment that has active group members. Registration
of the members is achieved with IGMP host membership report. Upon reception of such message each
upstream router between the receiver and the RP creates or updates its multicast route entry for specific
multicast group(s) adding interface where join/prune request have been received. When the RP receives
the join/prune message it sends join request toward the sender(s). Refer to user manual under section-
shared tree for drawing and additional protocol details.
A JOIN/PRUNE message contains, the upstream neighbor message, the multicast group address a router
wishes to join, number of joins and pruned source and the RP address.
Simplified Join Packet
IP: ----- IP Header -----
IP: Protocol = 103 (PIM)
IP: Source address = [192.168.12.2]
IP: Destination address = [224.0.0.13]
Com 3 Com 3 Com 3
Com 3
192.168.13.1
192.168.11.1
192.168.11.2
192.168.12.2
192.168.12.1
BSR
RP for 225.1.1.1
192.168.15.2
IGMP
membership
report 225.1.1.1
DR
DR
JOIN for 225.1.1.1
JOIN for 225.1.1.1
192.168.13.101
SENDER
225.1.1.1
RECEIVER
225.1.1.1