[c-nsp] seeking an advice about PIM DM riddle

[Roman A. Nozdrin]

Hi all.

I have several 7604+RSP720+6704card(12.2SRC) installed in a ring 
topology as a core part of our network. There is a multicast source 
attached with one of that 7600 routers. The routers successfuly use PIM 
DM to distribute multicast streams over the  ring.
Here comes the riddle. There is a situation when an intermediate router 
don't graft several streams, that are pruned in that moment. The streams 
are always random. I noticed, there are no Graft messages in a log on 
the intermediate 7600. The reciver can get such streams at the end of 
prune interval only.
I steered multicast to another arc of the ring to observe the situation. 
The problem shifted to another router.
Here is the question, is there any hardware limit or a caveate I have 
missed concerned with the behavior I described?

I will appreciate any suggestions on the situation.

WBR
Roman A. Nozdrin