Re: PM2e-30
Gary McKinney (gmckinney@megabits.net)
Thu, 10 Apr 1997 21:35:43 -0400
----------
> From: Stephen Fisher <lithium@cia-g.com>
> To: Jake (the flake) Messinger <jake@ams.com>
> Cc: John E. Kozitzki <johnk@rural-net.com>; Portmaster-users List
<portmaster-users@livingston.com>
> Subject: Re: PM2e-30
> Date: Thursday, April 10, 1997 6:54 PM
>
>
> How could that be? The PM2 can only tell two different things: The
> carrier was lost in the middle of a connection or the PPP user told the
> PPP stack on the PM that it wanted to log off at which point it would log
> "User-Requested."
>
> That's the way I see it. If the modems told eachother they wanted to
hang
> up (never know what modems do these days) the PM couldn't tell.
>
> On Thu, 10 Apr 1997, Jake (the flake) Messinger wrote:
>
> > Its probably being caused BY the modem itself. It detects line noise
and
> > believes that the line quality is no longer any good so it disconnects.
> >
> > I dont think its really a PPP request. The portmonster just THINKS it
> > is.
>
Yep ... If the modems told each other (or surmise by loss of carrier) they
will hang up with a "loss of carrier" as the signal (dropped DTR, I think)
whereas the PPP protocol would be the source of the "User-Requested"
indication - this could also be caused by many things - of which could be
CRC errors or framing errors. These types of errors could also be caused
by quick transit noise which had a smaller window than the carrier loss
detection circuitry in the modem(s).
Just my $0.02 (and has been the cause of most of our observed disconnects -
the telco was working on the lines between us and the CO)... This is a HARD
thing to determine (we had to put a dual-trace triggered storage
oscilloscope on the lines to "catch" the culprits!).
gm...