Post-meeting status of draft-RFC
hplabs!sytek!kzm (Keith Mc Cloghrie) Fri, 16 February 1990 03:13 UTC
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From: hplabs!sytek!kzm
Message-Id: <9002160239.AA04735@sytek.hls.hac.com>
Subject: Post-meeting status of draft-RFC
To: mogul
Date: Thu, 15 Feb 1990 18:39:46 -0700
Cc: hplabs!mtudwg
In-Reply-To: <9002142051.AA01873@acetes.pa.dec.com>; from "Jeffrey Mogul" at Feb 14, 90 1251
X-Mailer: ELM [version 2.2 PL0]
Jeff, In talking to others since the PMTU-Discovery Working Group meeting last week, I've discovered that not everybody was left with the same impressions. The whole question of which method is best seems to me a matter of choosing the right trade-off: how much fragmentation is avoided v. the amount of processing/state information in various places. I certainly like the fact that using the RF bit avoids having to keep state at the destination. But none of its variants that I've heard so far are as good at avoiding fragmentation as the proposal in the draft RFC handed out at the meeting. If the bit is made available for PMTU-discovery, then I look forward to seeing how good a proposal that Van/Steve/Mike can come up with. (Note that there are a number of issues that they still need to resolve; for example, to decide on a method of determining whether the destination is prepared to send Frag-Report ICMP messages; the discussion at the meeting didn't resolve this and didn't address UDP either. It occurs to me that they could send an IP option to ask the destination explicitly, but I'm sure they'll find something more creative, which will also cover the possibility of packet loss/etc.). On the other hand, if the bit is still not available (or if Van, Steve & Mike can't find the time to write up their proposal), then as I said at the beginning of the meeting last week, I see the draft-RFC as the combination which produces the least fragmentation. I believe it's worthwhile to evaluate the removal of capabilities from this combination, to determine whether such removal results in a gain in simplification which outweighs the corresponding increase in fragmentation. Keith.
- Post-meeting status of draft-RFC Keith Mc Cloghrie