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From: brescia@BBNCCV.ARPA (Mike Brescia)
Newsgroups: mod.protocols.tcp-ip
Subject: Re: Space wars
Message-ID: <8512050021.AA17933@ucbvax.berkeley.edu>
Date: Wed, 4-Dec-85 16:35:32 EST
Article-I.D.: ucbvax.8512050021.AA17933
Posted: Wed Dec  4 16:35:32 1985
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The BBN gateways current version does not use memory mapping in the lsi11.
(There are even some of the machines which are 11/02 without mapping hardware.)
The tradeoff in memory is between packet buffers and routing table entries.
Currently, the buffer capacity at some sites is just enough to absorb a bunch
of packets from an ethernet (fast) sending out to an arpanet (slow) for a
single ftp connection.  In those cases, losing one buffer causes the
probability of packet dropping to increase dramatically.  Just ask the people
at ISI.

Memory mapping is included in a new version of software which is now running
on a machine between bbnnet and arpanet and a local ethernet (which is to say
that it is beyond debugging and into testing).  In a couple of weeks, it
should be released to some sites which have memory mapping hardware (11/23
processors).  The arpanet-milnet gateways are being placed under configuration
management, and should be ready for release with memory mapping in a couple of
months.

Memory mapping will allow extra memory to be used for buffering and allow more
networks to be listed.

	Mike Brescia