Vadim Antonov <avg@titan.sprintlink.net> Wed, 12 January 1994 23:49 UTC

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Date: Wed, 12 Jan 1994 17:13:22 -0500
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From: Vadim Antonov <avg@titan.sprintlink.net>
Message-Id: <199401122213.RAA17983@titan.sprintlink.net>
To: catnip@world.std.com

TTL:

>We still want a nominal time associated with it, for when a router
>hangs onto a datagram for a longer than usual time (typically waiting
>for some kind of subnetwork setup). Probably 1/10 second is good; it
>must be less than IP's (1 sec) and less than CLNP (500 msec)

>It also seems that 8 bits is really sufficient.

Not at 1/10 seconds!  The problem is that there are links which
can delay a packet for up to a minute while establishing a connection.
We'll see more and more of them with the proliferation of dial-up IP
and the real cheap 19.2Kbps modems.

[Discarding a packet which initiated the connection is also not a good
idea because it's most likely a TCP init packet which will be retransmitted
with large delays and user is already irritated :-)]

I would propose "logarithmic" time -> TTL translation; i.e.

	1/16 sec delay equals 1 hop
	1/8 sec == 2 hops
	1/4 sec == 3 hops

etc.  I'm not sure what the implications of that scheme are.

--vadim

Vadim Antonov
tracym
Re: (it must be lost) Matt Crawford