C-RP Advertisements Troubleshooting PIM-SM
page 16-10 OmniSwitch Troubleshooting Guide September 2005
C-RP Advertisements
Candidate-RPs advertisements are periodically unicast from the C-RP to the BSR. These advertisements
contain group multicast address the router can be responsible for and the priority for the corresponding
group address. C-RP could be configured to participate as RP for specific multicast groups or for all multi-
cast groups. Highest priority will be 0. Other parameters present in the packet are:
• Holdtime timer, which is the amount of time the advertisement, is valid.
• The prefix count, which tells the number of group addresses contained in the advertisement.
• The unicast RP address which is the interface to advertise as RP.
• The mask length.
Simplified RP-Advertisement Packet Format
IP: ----- IP Header -----
IP: Protocol = 103 (PIM)
IP: Header checksum = DF9E (correct)
IP: Source address = [192.168.10.3]
IP: Destination address = [192.168.11.1]
IP: No options
IP:
Com3 Com3
Com3
Com3
192.168.11.1 192.168.11.2
192.168.10.2
192.168.10.3
192.168.9.4
192.168.9.2
BSR
C-RP-Adv
RP address 192.168.10.3
Mluticast Group 225.1.1.1
