Re: (PM) Disconnect status?

Matthew Walker (mwalker@lidcam.com.au)
Wed, 12 May 1999 11:08:29 +1000

"Michael Bryan" <pmu@ursine.com> writes:
>On 5/11/99 at 1:23 PM Craig Baird wrote:
>
>>Yup, I've come to the same conclusion. I've actually tested it. I'll
>>connect to a modem showing CIRCUIT DISCONNECT, then I'll disconnect
>>normally (hitting the Disconnect button in Win95). I check the modem I
>>was connected to, and it still shows CIRCUIT DISCONNECT, althought the
>>number of calls has gone up by one. If I go and check the RADIUS
>>detail, it shows that my disconnect reason was "User Request - PPP Term
>>Req"--A normal disconnect.
>
>Has anybody actually opened a ticket with support over this issue?
>Especially anyone who has taken the time to document and verify this
>behaviour?

Below I've reposted a message I sent to the list back in January explaining
what happens and why the disconnect causes you see with a show modems are
basically impossible to interpret.

Matthew

email@rcip.com writes:
>What is the difference between:
>
>LAPM DISCONNECT
>CIRCUIT DISCONNECT
>LAPM RETRY LIMIT
>(Are there is others that I did not list?)
>
>Is one of them worse than another? We have had a lot of users telling us
>they are constantly being disconnected (a couple employees are complaining
>of the same problem) and we are unaware of a solution. We are trying to
>explore all possibilities.

These are disconnect causes listed when you do a show modems and due to the
real upper layer causes being both good and bad are basically irrelevant.
You really need to be looking at the termination causes that are syslogged
if termination syslog is enabled or ideally be using a Radius server (such
as Lucent RABU's 2.1b6) that supports Vendor Specific Attributes,
specifically LE-Terminste Detail. These give a much clearer idea of the
state of the connection when it was terminated (although they to could do
with a lot of improvement IMHO).

The causes you list above boil down to:

LAPM DISCONNECT:

The remote modem asked to disconnect and this was negotiated at the LAPM
level. Good.

CIRCUIT DISCONNECT:

The PortMaster sent or received an ISDN message resulting in the hangup of
the line. This can be good or bad.

Good: The PortMaster received a PPP Termination Request packet from the
client asking to disconnect. The ISDN part of the PortMaster manages to
hangup the phone line before the modem part disconnects, resulting in a
CIRCUIT DISCONNECT being logged for the modem (the LE-Terminate-Detail and
syslog log User Request - PPP Term Req)

Bad: The PortMaster received an ISDN message from the telephone switch
saying the other end had hung up. This is logged by LE-Terminate-Detail as
User Request - Call Circuit Closed.

LAPM RETRY LIMIT:

The two modems had too many errors in a certain period of time and reached
the limit of the number of retries so they disconnected. Bad.

Matthew Walker, Technical Support Lidcam Technology
Ph: 61 3 9820 9077 Level 5 499 St Kilda Rd
Fax: 61 3 9866 1245 Melbourne VIC 3004
<http://www.lidcam.com.au/users/matthew/> AUSTRALIA
<mailto:mwalker@lidcam.com.au>
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