Subject: [pim] Doubt abt Assert Message

From: "dsa main" <[email-masked]>
Date: Mon, 23 Feb 2004 22:23:08 +0000

Hi All,

I have a doubt regarding Assert message sending.

Assume a router became an "assert winner" on an interface and it starts 
sending assert messages. Later if the router dont see any "hello" messages 
on the interface whether it should stop sending
assert messages ?

Regards
dsa

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From: Pavlin Radoslavov <[email-masked]>
Date: Mon, 23 Feb 2004 15:09:11 -0800

[Response redirected to the new [email-masked] address instead
because the old address [email-masked] is not valid].

> on the interface whether it should stop sending

The answer is that the Assert winner will keep transmitting Assert
messages on an interface until the CouldAssert() macro is true, or
until it becomes an Assert loser.

Hence, it may look like that the Assert winner will keep
transmitting Assert messages even if there are no neighbors on an
interface. However, if there are no more Hello messages on an
interface, all the neighbors will eventually timeout. As a result of
this timeout the PIM join state on that interface will timeout as
well, and eventually CouldAssert() for that interface will become
false.

Indeed, if you look closely into the CouldAssert() definition you
can notice that if there are receivers on the LAN for that interface,
then CouldAssert() would still be true so the router will keep
transmitting the Assert messages even if there are no PIM neighbors.
Whether it is worth optimizing this corner case, I don't know.
But such optimization will make the Assert state machine look even
more complicated.
A strawman solution could be "If I am in Assert Winner state and if
Assert Timer Expires and if there are no more PIM neighbors, then
the assert state-machine should transitinto NoInfo state".
Such optimization could be left to the implementation itself.

Pavlin

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From: Pavlin Radoslavov <[email-masked]>
Date: Mon, 23 Feb 2004 15:09:11 -0800

Pavlin