All things related to multicast

[Leonard Giuliano <>]

Jose- somewhere between the Houston router and the other I2 router with 
the output, the SA from 233.73.103.142/138.237.xx.205 is getting dropped.  
Most likely it is being rejected bc it fails MSDP peer-RPF.  Go to the 
peers of Houston that you would expect to be sending Houston this SA, and 
do the same "show msdp sa" command.  You will most likely see one that has 
this SA, but it is rejected from all of it's peers (none of them will be 
accepted for this SA).  Repeat this process until you find that router 
which has received these SAs, but rejected them all.

Then you need to determine why it's being rejected (assuming it is being 
rejected).  Do a "show route extensive <Peer address>" and a "show route 
extensive <Originator address>".  Then you will be able to see why 
peer-RPF is failing- it will not be satisfying one of the MSDP RPF rules 
in sect 10.1.3 of RFC 3618.

If you send me those outputs, I can help determine the RPF problem.

-Lenny

On Tue, 6 Apr 2010, Feghali, Jose wrote:

-) We are trying to debug some multicasting problems here and have used the 
I2 router test page. One strange thing is happening and I wonder if it would 
be "normal" behavior:
-) 
-) Doing an mtrace on the Houston router shows only two clients on this mcast 
group (there are three):
-) 
-) .............> show msdp source-active group 233.73.103.142
-) Group address   Source address  Peer address    Originator      Flags
-) 233.73.103.142  138.237.xx.197  74.200.187.6    138.237.224.3   Accept
-)                                 200.23.60.121   138.237.224.3   Reject
-) 233.73.103.142  139.80.xxx.146  64.57.28.247    139.80.247.225  Accept
-)                                 200.23.60.121   139.80.247.225  Reject
-) 
-) Every other router on I2 gives all three:
-) 
-) 
-) .............> show msdp source-active group 233.73.103.142
-) 
-) Group address   Source address  Peer address    Originator      Flags
-) 
-) 233.73.103.142  138.237.xx.197  64.57.28.244    138.237.224.3   Accept
-) 
-)                                 138.18.9.253    138.237.224.3   Reject
-) 
-)                                 206.196.177.105 138.237.224.3   Reject
-) 
-) 233.73.103.142  138.237.xx.205  64.57.28.244    138.237.224.3   Accept
-) 
-)                                 138.18.9.253    138.237.224.3   Reject
-) 
-)                                 206.196.177.105 138.237.224.3   Reject
-) 
-) 233.73.103.142  139.80.xxx.146  64.57.28.247    139.80.247.225  Accept
-) 
-)                                 138.18.9.253    139.80.247.225  Reject
-) 
-)                                 206.196.177.105 139.80.247.225  Reject
-) 
-) Houston is the closest I2 router to us.
-) 
-) Any ideas if this is correct behavior or, if not, where should we look?
-) 
-) Thanks,
-) 
-) Jos? Feghali
-) TCU School of Music
-) 
-)