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Re: [RFC/PATCH] "strict" ipv4 reassembly

To: netdev@xxxxxxxxxxx
Subject: Re: [RFC/PATCH] "strict" ipv4 reassembly
From: Rick Jones <rick.jones2@xxxxxx>
Date: Tue, 17 May 2005 14:25:19 -0700
Cc: netdev-bounce@xxxxxxxxxxx
In-reply-to: <20050517.140245.71090021.davem@xxxxxxxxxxxxx>
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this may be drifting tooo much, but it seems the issue of deciding when to give-up on reassembly of an IP datagram is similar to the issues that neterion are going to be going-through creating their "LRO" (Large Receive Offload) solution, albeit the potential consequences of a bad decision are rather different.

both seek to know when it is unlikely that no more frames/fragments will arrive.

just how much extra overhead would there be to track the interarrival time of ip datagram fragments and would that allow someone to make a guess as to how long to reasonably wait for all the fragments to arrive? (or did I miss that being shot-down already?)

or an added heuristic of "if have reassembled N datagrams for the same source/dest/protocol tuple with ID's "larger" than 'this one' since it has arrived, we are probably going to wrap so might as well drop 'this one'" for some judicious and magical selection of N that may be a decent predictor of wrap on top of some existing reassembly timout.

rick jones

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