Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!husc6!cmcl2!sbcs!root
From: root@sbcs.sunysb.edu (SBCS System Staff)
Newsgroups: comp.protocols.tcp-ip
Subject: Discarding fragment assembly queues in low mem situation
Message-ID: <5564@sbcs.sunysb.edu>
Date: 19 Feb 90 04:45:20 GMT
Sender: root@sbcs.sunysb.edu
Organization: State University of New York at Stony Brook
Lines: 14

I have a port of Berkeley TCP-IP that I am interested in tuning.  One
area that is causing some trouble is the management of the fragment assembly
queue in a low/no memory situation.  The current Berkeley code simply
flushes all the fragment queues when the system is out of network
buffers.  One possible solution would be to LRU the queues out, but the
claim I heard was this will unduly penalize long delay networks.  Another
solution recommended was to just randomly discard queues when out of memory.
Does anyone have a better algorithm than the two discussed here?  It would
seem that something along the lines of LRU modified with information about 
average packet arrival rate would be more appropriate (but is it worth the
extra work).

					Rick Spanbauer
					State U of NY/Stony Brook