PIM-SM always sent unicast to RP

seekianherng · ‎12-10-2007

hi,

Mcast_src---cat4948---Firewall---(RP)cat6513-720---Mcast_client

I'm trying to pass multicast traffic through the firwall and was wondering if its possible to force PIM-SM to always sent unicast packets (Register message) to RP without switching to SPT on the source-tree.

I understand that the other option is to use GRE tunnel between the two switches.

Edison Ortiz · ‎12-10-2007

ip pim spt-threshold infinity should help on this requirement

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/himc_c/mcboptim.htm

seekianherng · ‎12-10-2007

hi EdisonOrtiz,

The infinity command seems to indicate that it only prevent SPT switching on the PIM leaf router (shared-tree path from RP) and not on the source-tree path between the multicast source and RP.

Mcast_src---source_tree--->RP---shared_tree--->Mcast_dest

I'm also wandering if constant encap-decap of multicast packets will cause dramatic increase in cpu load on both switches.

Is there a better way for sending multicast packets through the firewall ?

Edison Ortiz · ‎12-11-2007

I believe you hit it on the nail on the first post, your only valid option (IMHO) is GRE tunneled - per your requirements.