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From: AI.CLIVE@MCC.COM (Clive Dawson)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: problems with IMP connection hanging
Message-ID: <12345615539.23.AI.CLIVE@MCC.COM>
Date: Mon, 26-Oct-87 13:51:36 EST
Article-I.D.: MCC.12345615539.23.AI.CLIVE
Posted: Mon Oct 26 13:51:36 1987
Date-Received: Fri, 30-Oct-87 06:26:16 EST
References: <8710250154.AA11004@topaz.rutgers.edu>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 33

Our DEC-2065 host (MCC.COM) also uses ECU's to connect to the UTexas
PSN.  We've had a trouble-free connection for almost 3 years now.
We've had to deal with a hand-shaking problem, because apparently
the ECU will not raise the IMP ready signal until it sees host ready,
and the TOPS-20 operating system will not raise host ready until it
sees IMP ready.  So we run a small program called AN20-HACK at system
startup time, which uses a DATAO to force host ready on, and all
goes well from then on.  If the PSN happens to go down, however,
then TOPS-20 drops host ready, and AN20-HACK must be run again
when the PSN comes back up.  Otherwise the connection will stay
down for hours until somebody notices.

To solve this problem, I created a small batch job that runs
every 30 minutes to check the status of the net.  If "INFO ARPA"
shows that the net is down, then AN20-HACK is run to try and
get things started again.

All of the above is background info to get around to the real
point of this message.  Last Friday I noticed that the H/I RFNB
light on our ECU was out.  I ran AN20-HACK, which is the normal
way to cure this, but noticed that the light stayed out.  Then
I noticed that "INFO ARPA" reported that the network was UP!
(Perhaps it simply checks "host ready"?)  This is the first time
I had ever noticed that the system reported that the net was
up when in fact it was down.  I pushed RESET on the ECU, ran
AN20-HACK once more, and all was back to normal.

The problem has not recurred since.  I don't know if this is
in any way related to the problem you reported, but I suspect
it might be.  In any case, I hope this is of some help.

CLive
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