Alcatel Carrier Internetworking Solutions 6800 User Manual

Join/Prune

Troubleshooting PIM-SM

page 16-18

OmniSwitch Troubleshooting Guide

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.

IP: ----- IP Header -----

      IP: Protocol        = 103 (PIM)

      IP: Source address      = [192.168.12.2]

      IP: Destination address = [224.0.0.13]

      

192.168.13.1

192.168.11.1

192.168.11.2

192.168.12.2

192.168.12.1

192.168.15.2

IGMP

membership

report 225.1.1.1

192.168.13.101