Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!yale!mintaka!spdcc!dyer
From: dyer@spdcc.COM (Steve Dyer)
Newsgroups: comp.dcom.sys.cisco
Subject: Re: help needed debugging DDS 56kb prob
Message-ID: <3961@ursa-major.SPDCC.COM>
Date: 9 Sep 90 03:20:52 GMT
References: <3951@ursa-major.SPDCC.COM>
Reply-To: dyer@ursa-major.spdcc.COM (Steve Dyer)
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 28

In article <3951@ursa-major.SPDCC.COM> dyer@ursa-major.spdcc.COM (Steve Dyer) writes:
>[problems of hundreds of carrier transitions and serial line resets]

The problem has disappeared, and the superficial solution was simple
(if that was in fact the source of the problem.)  I'd specified the
high-speed serial interface on my CGS/2 even though I was planning to
run at 56kb so that I could upgrade simply to fractional T1 speeds if my
downstream link ever upgraded also.  During the initial configuration
of the serial interface, we neglected to specify the line bandwidth as 56kb
(since that was what had been assumed for other CGS/2 models, and was
the default for the Cisco on the other end of the DDS line.  Apparently
though, the default for the high-speed serial interface is T1 rate.
Once I reset this to 56kb, things settled down within minutes, and
I've had only a few carrier transitions and no interface resets since.

I suppose that the "bandwidth" field is used for the initial values
of the HDLC timers, and having such a mismatch between the two sides
(not to mention the actual bandwidth) could cause problems, no? 

By the way, I really have to say that I'm impressed how easily it
is to install one of these gateways and have it all work--it's
practically a "turnkey" operation.  Things have come a long way
since the original LSI-11 gateways when I was at BBN... :-)

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
dyer@arktouros.mit.edu, dyer@hstbme.mit.edu