Re: (PM) disconnect reasons

Matthew Walker (mwalker@lidcam.com.au)
Wed, 3 Mar 1999 15:18:30 +1100

mike@sentex.net (Mike Tancsa) writes:
>On 2 Mar 1999 20:37:27 -0500, in sentex.lists.livingston you wrote:
>
>>Hi,
>>
>>Can someone interpret what a 'call circuit closed' means? What causes it?
>
>Have a look at http://www.livingston.com/tech/docs/trb/termin.fm.html,
>specifically,
>-----------------
>The telephone company dropped the digital signal level 0 (DS0) circuit that
>user was on for one of the following reasons:
>
>Remote modem in an on-hook condition
>
>Three invalid login attempts
>
>Sudden line termination
>
>Remote modem turned off
>------------------
>Although this would imply that its the other end that caused the problem,
>if you do a "reset M0" on the portmaster, the termination will be CCC. I
>interpret the CCC as being x+y=total CCCs, x=fault of the pm3, y%=fault of
>the remote modem. As to what ratio x is to y, is hard to say, but the Call
>Circut Closed corelates VERY highly to my customers having random
>disconnect problems.
>
>Someone once on the list analyzed the ISDN chatter through this process and
>said it was indeed the remote end hanging up. However, you could also
>interpret this as being the PM modem code sent 'something bad' to the
>remote end which then hangs up. It would be real nice if Livingston could
>give a more complete explanation, but I have yet to see one :-(

Call Circuit Closed is logged as the disconnect cause when the PM receives
a disconnect message from the switch while the modem in the PM believes it
is still connected.

Lost Carrier occurs when the modem in the PM decides it has lost the
connection and it then disconnects the line.

It's all about timing. If the PM modem decides it's disconnected it's a
Lost Carrier, if the remote modem decides it's disconnected it hangs up and
causes a Call Circuit Closed.

In the instance where you issue the reset mX command the serial code in the
PM does not seem to recognise this and keeps the connection up, eventually
the other modem decides it has lost the connection and hangs up the line.
The PM then receives a disconnect from the switch and logs a calll circuit
closed.

Of course not all CCC's are the fault of the PM, some will be people
turning off or unplugging modems, some may be call waiting, some may just
be due to some transient fault on the line. Some also are, the PM modem
loses connection with the remote modem and can't bring it back up for
instance.

Lost Carriers are also strange. In my experience the PortMaster logs all
calls that are never connected as Lost Carrier (which I see as correct,
although a separate cause like Failed Connect would be good IMHO). However
once the modems actually connect the PM modem seems to have a much greater
timeout value than most client modems resulting in a very low percentage of
Lost Carriers in LE-Terminate-Detail compared to CCC as the remote modem is
timing out first and dropping the line.

I hope this helps.

Regards

Matthew Walker

Matthew Walker <mailto:mwalker@lidcam.com.au> Lidcam Technology
Ph: +61 3 9865 9077 Level 5 499 St Kilda Rd
Fax: +61 3 9866 1245 Melbourne VIC 3004
<http://www.lidcam.com.au/users/matthew/> AUSTRALIA
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