Path: utzoo!utgpu!water!watmath!clyde!bellcore!faline!thumper!ulysses!andante!mit-eddie!bbn!uwmcsd1!ig!agate!ucbvax!PANDA.PANDA.COM!MRC
From: MRC@PANDA.PANDA.COM.UUCP
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Linking LAN's via Public X.25
Message-ID: <12403803889.8.MRC@PANDA.PANDA.COM>
Date: 4 Jun 88 18:09:46 GMT
References: <12403549643.58.LYNCH@A.ISI.EDU>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 27

Dan -

     I'm responsible for one of the TCP/IP implementations used on a
9600 baud link in Canada.  The system is a DEC-2065 running a TOPS-20
with a heavily modified TCP.  It has two IP interfaces; a NIA20 to the
local Ethernet and an AN20 to a C/30 PSN using 1822.

     This TCP lacks RFNM counting which is a serious deficiency, but
in the case of this link it doesn't really matter all that much since
(at least the last I read) there is only one place for the 1822-grams
to go to.  If you're RFNM blocked to the friendly not-so-local gateway,
you can't do anything anyway.

     What makes the burden worse, this machine is the only path between
the local Ethernet (which talks TCP/IP and DECnet) and the rest of the
world.  It has a rudimentary EGP-speaker that babbles updates to Friend
Gateway.

     I've seen no indication of a bottleneck at the DEC-20.  Instead,
it seems to be more that the DEC-20 (and the Symbolics Lisp machines
behind it on the Ethernet) are communicating almost exclusively with
the Internet in the US, across two gateways over a long long wire.
There isn't all that much traffic to begin with, so any latency in a
connection can easily stop the line...because there is no other traffic!

-- Mark --
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