Re: modem training failures across long distance

Ron Parker (rparker@gator1.brazosport.cc.tx.us)
Fri, 23 May 1997 10:38:41 -0500 (CDT)

I see something similar when some of our inbound calls cross telcos. For
example, we have some lines in a rural town that go via a 100+ mile loop
through multiple COs before they actually get to us (we're actually about
30 miles from where they start). We have various problems with these
lines that have all been traced to interoffice trunking between
Southwestern Bell and Fort Bend Telephone. The symptoms we typically see
are significantly lower connect speeds depending on which line the caller
happens to grab. I'm not sure if this is your problem, but that's where
I'd start looking given the symptoms you've described.

I know there is someone on this list from USWest who seems to know telco
stuff far better than I (that doesn't take much, unfortunately). Perhaps
they can respond about how to handle these intertelco issues? I generally
just get the two telcos pointing fingers at each other.

--
Ron Parker, Brazosport College

On Mon, 19 May 1997, Tim Hodges, Triangle Telephone Cooperative wrote:

> Greetings.. > > Okay here is the set up. > > I have a PM-3, with 2 CT-1's feeding it. Running 3.5.1b8. Our company is both > the ISP and a local rural telco. > > I am going to be supplying service to a telephone exchange several hundred > miles from > here. The phone calls from that exchange are forwarded across our fiber optic > telephone network to our main CO/modem location. > > If I call the PM-3 from my main telephone exchange where the PMs are located: > works great. > > If I call the PM-3 from the remote telephone exchange: > works great. > > If I make a long distance call from my main location to the telephone number > at the remote exchange: the call goes through, but the modems fail to train. > > The failed phone calls leave my main phone switch, go across the US West > toll network, hit my remote exchange and then get forwarded back to my PM-3s. > > Some of the phone goes say it is the cumulative propagation delays that are > causing the failure. I disagree. I think it is some conditioning in the phone > network that is causing the problem. > > I would appreciate any input from users who have more telephone network > knowledge or experience in similiar situations. I will probably open a ticket > with livingston today, but thought I would start here. > > Thanks, > > Tim Hodges > Triangle Telephone Cooperative > 7thodges@3rivers.net >