RE: multicast question.

From: Vincent Mashburn (vmashburn@fedex.com)
Date: Mon Oct 09 2006 - 10:33:35 ART


Since you are using sparse mode and you stated that sometimes it pings
and sometimes it doesn't, this sounds like a possible spt cutover issue.
The RPF check may pass for traffic routed to the RP, but when the SPT
kicks in, the RPF may fail. I would suggest trying BIDIR and see if
everything works fine there. If that works, then try using Sparse-mode
again, but with "spt-threshold infinity". If this also works, then you
know you have a RPF problem in your SPT. Hope this helps.

Vince Mashburn
Voice / Data Engineer
901-263-5072
CCVP, CCNP, CCDA,Network +
Cisco IP Telephony Support Specialist
Cisco IP Telephony Operations Specialist

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
riaz shams
Sent: Saturday, October 07, 2006 4:28 PM
To: ccielab@groupstudy.com
Subject: multicast question.

hi group ,

can anyone pls clear my doubt on this,

three routers, R1 R2 and R3 connected on frame -relay hub and spoke
style.
R2 is hub. OSPF is running as a routing protocol and R3's one interface
is
not part of ospf.

i have given igmp-join group on ethernet's interface of R3 and multicast
is
running on all three routers.

now if i ping from R1 to that multicast address , it sometime pings and
sometimes not.
i have also checked RPFs and RP mappings.

do i need to bring that interface's subnet in routing domain for
multicast
address to be pingable ?

Tia
riaz.



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