Subject: Re: [[email-masked]: RE: Assert on outgoing interface]

From: Bill Fenner <[email-masked]>
Date: Tue, 17 Nov 1998 12:10:55 PST

I was engaging in a bit of hyperbole.  Forgive me.

No matter how large or small N might be, having the protocol specify that
the Assert winner sends 1 packet still seems to be better than having the
protocol specify that the Assert winner sends about N packets.

  Bill

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From: Liming Wei <[email-masked]>
Date: Tue, 17 Nov 1998 11:48:47 -0800 (PST)

------- Start of forwarded message -------
> From: Bill Fenner [SMTP:[email-masked]]
> 
> Except it's N-1 assert messages; in a pathological case, with
> 100 routers on the LAN, the Assert winner could be sending 99
> "I-won-the-Assert" messages.

I have repeatedly seen references to this example, and would like to
clarify it. On this LAN, you don't have 100 forwarders for each
source. "N" should be the number of forwarders on parallel paths to a
source, not the total number of routers on a LAN.

So you don't have 99 "I-won-the-Assert" messages.

When engineering a network, if "N" is greater than 2 or 3, there
is diminishing return on robustness, and less justifiable economically.
In the very unlikely case when people do have a large N,
they will not use dense mode even if they don't care about
control message overhead.

-Liming

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From: Liming Wei <[email-masked]>
Date: Tue, 17 Nov 1998 14:11:42 -0800 (PST)

> X-SMAP-Received-From: outside
> Sender: Bill Fenner <[email-masked]>
> 

No problem, Bill.

> protocol specify that the Assert winner sends about N packets.

A good thing to say in general. And I realize the word "SHOULD" is not
in the place I thought it were. Will try to fix it. The reason to not
*forbid* the sending of assert after a router wins is so that an
implementation can make tradeoffs (without affecting the correctness
of the protocol). This accommodates your suggestion of further
optimization, while leaving room for implementation choices, yes ?

-Liming