Re: packet reordering at exchange points

["E.B. Dreger" <eddy+public+spam () noc everquick net>]

> Date: Tue, 9 Apr 2002 00:32:50 +0200 (CEST)
> From: Iljitsch van Beijnum <iljitsch () muada com>


> Obviously some applications care. In addition to the examples mentioned
> earlier: out of order packets aren't really good for TCP header
> compression, so they will slow down data transfers over slow links.

How about ACK?  I think that's the point that Richard was
making... even with SACK, out-of-order packets can be an issue.


> But how is packet reordering on two parallell gigabit interfaces ever
> going to translate into reordered packets for individual streams? Packets

Queue depths.  Varying paths.  IIRC, 802.3ad DOES NOT allow round
robin distribution; it uses hashes.  Sure, hashed distribution
isn't perfect.  But it's better than "perfect" distribution with
added latency and/or retransmits out the wazoo.


> for streams that are subject to header compression or for voice over IP or
> even Mbone are nearly always transmitted at relatively large intervals, so
> they can't travel down parallell paths simultaneously.

What MTU?  Compare to jitter multiplied by line rate.


--
Eddy

Brotsman & Dreger, Inc. - EverQuick Internet Division
Phone: +1 (316) 794-8922 Wichita/(Inter)national
Phone: +1 (785) 865-5885 Lawrence

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