Interdomain Multicast Routing: Practical Juniper Networks and Cisco Systems Solutions

Appendix B. PIM Packet Formats

This appendix includes the packet formats from the specifications of the two versions of PIM.

PIM Version 2 Packet Formats

PIMv2 is the result of the collective work of Bill Fenner, Mark Handley, Hugh Holbrook, and Isidor Kouvelas. The packet formats are described in section 4.9 of the current specification, which is included here in its entirety (it has been reformatted for consistency).

PIM Packet Formats

This section describes the details of the packet formats for PIM control messages.

All PIM control messages have IP protocol number 103. PIM messages are either unicast (e.g., Registers and Register-Stop) or multicast with TTL 1 to the ALL-PIM-ROUTERS group (e.g., Join/Prune, Asserts, etc.). The source address used ...