Re: The future of ICP_OP_HIT_OBJ

From: Ingrid Melve <>
Date: Thu, 20 Nov 1997 09:14:13 +0100

> Duane Wessels:
> I'd like to get an idea of to what extent people think the ICP HIT_OBJ
> feature is a good idea to continue supporting.

The main reason to support ICP_HIT_OBJ is speed, and the limiting factor today is setting up the TCP connection instead of getting the (small) object via ICP. With persistent connections this slow-down is removed, and there is no reason to keep ICP_HIT_OBJ. My gut feeling is to slay ICP_HIT_OBJ the minute we have persistent connections.

Regarding the evils of ICP_HIT_OBJ:
 - fragmentation does occur (I'll try to dig up my measurement of this if needed) for ICP and is evil
 - congestion has not been a problem caused by ICP, mainly because HTTP/1.0 over TCP takes care of congesting links/networks
 - reading from disk takes much less time than sending over network in my experience (but then my caches are some thousand/hundred kilometers apart;)
 - traffic minimization is not a big issue for those with several parents/sibling, as ICP_HIT_OBJ generates extra traffic (only the ones use are logged by Squid, there is more traffic on the link)
 - <paranoid> it is possible to spoof ICP_HIT_OBJ replies with false documents, this is easier to do with multicast ICP</paranoid>


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Received on Thu Nov 20 1997 - 00:09:42 MST

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