Subject: doubts regarding assert mechanism in PIM SM

From: sabarivel s <[email-masked]>
Date: Tue, 28 Mar 2000 12:33:30 +0530

hi ,
 i have some doubts regarding the assert mechanism (refer PIM -sm rfc 2362 
 section 3.5)

1) in the section 3.5.2.2 Receving asserts on an entry's incoming interface 
		
doubt :  if the assert does not match the entry exactly it is ignored.What 
do u mean by exact entry in this context ? 	
	is the RPT bit of the assert messages are taken care in this case?
             i.e if the RPT bit is cleared exact matching entry is (s,g)
	 and if RPT bit is exact matching entry is (*,G) . Is it so?

doubt :  When the RPF neighbour changes Assert timer has to be started .. 
and random delay join timer also need to be started.
	Which timer has to be started first?

2)  in the same section 3.5.2.2. point no 2 is
If the downstream routers have downstream members and if the assert caused 
the RPF neighbour to change the downstream routers must trigger a 
join/prune message to inform the upstream router that packets are to be 
forwarded on the multiaccess network.

doubt: whether a prune has to be sent to the old RPF neighbour? if prune is 
to be sent ,whether join/prune suppression timer
	 has to be started by other routers parallel to it?
          when the downstream routers don't have downstream members what to 
do?

thanks in advance
with regards
sabaris

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From: Renu Agarwal <[email-masked]>
Date: Wed, 29 Mar 2000 11:08:51 +0530

Hello sabarivel,
Please see my replies.  

Hope it helps,

Renu
>          and if RPT bit is exact matching entry is (*,G) . Is it so?

If RPT-bit is set then depending on the group address present match it
exactly with (*,G) or (*,*, RP).

else
	match with (S,G)entry

>         Which timer has to be started first?

The timers has to be started simultaneously. In my opinion, the sequence
is immaterial.
> has to be started by other routers parallel to it?
The RFC nowhere specifies the prune is to be sent. It assumes that the
old RPF shall automatically time-out the entry in absence of join-prune
message.

>           when the downstream routers don't have downstream members what to
This is totally different case. If a downstream router has no downstream
members or routers using that entry, this entry shall any way be
deleted/timed-out.