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From: MRC@PANDA.COM (Mark Crispin)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: DDN X.25 mapping
Message-ID: <12334620403.6.MRC@PANDA.COM>
Date: Mon, 14-Sep-87 16:13:31 EDT
Article-I.D.: PANDA.12334620403.6.MRC
Posted: Mon Sep 14 16:13:31 1987
Date-Received: Tue, 15-Sep-87 07:07:57 EDT
References: <malis@CC5.BBN.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
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For the record, both BBN and PANDA TOPS-20 assume that any Class C
PSN-based network will have the host number in the high order 2 bits,
and the PSN in the low order 6 bits of the fourth octet.  This is the
format which we used in the good old days of NCP and 32-bit leaders,
for those of us old enough to remember that far back (am I betraying
my age????).

DEC TOPS-20 doesn't handle non-class A PSN's at all, nor does any
version of TOPS-20 I know of handle X.25 interfaces (the DEC IMPterface
is an 1822 device).  I think that DEC is adopting the PANDA algorithm
though.

I know of no controversy about the format a Class B PSN network address,
or, at least TOPS-20 and Unix agree on having the host number in the
third octet and the PSN number in the fourth octet.
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