Ascend Archive
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Re: (ASCEND) ISDN dial out problem/q.931 tracing

On Wed, 28 Jan 1998, Kevin A. Smith wrote:

> At 09:39 PM 1/27/98 -1000, Brian Uechi wrote:
> >We were running bi-directional isdn with no problems for at least a
> >year but suddenly dial out stopped working. 
> 
> And NOTHING changed?
> 
> >Dialing in continues to
> >work normally. We've tried 5.0Ap16 (this worked fine) and 5.0Ap36.
> 
> You say p16 worked fine...is that past tense, i.e. it doesn't any longer?

The unit was running p16 w/ v.34 modem cards. We replaced the modem
cards with k56 cards and upgraded to p36. Since then isdn dial out
has not worked. We removed the k56 modem cards (v.34 cards sent back
to ascend) and reverted to p16 but this has not helped.

> >The disconnect cause code is 44. Any idea what could cause this? GTE
> >sent a technician out with a pri tester and was able to make a call
> >on the same pri after disconnecting the max. Also testing of the pri
> >facility shows no problems.
> 
> What are your PRIs setup for? Do you have them configured for NFAS, or
> regular PRI? Have you changed that configuration at all recently?

ESF, B8ZS, NTI, FAS, 23 circuit switched data channels, D channel on
24.  No config changes we know of. Dial in has continued to work
without problems.

> Has GTE changed anything their end? (Like upgrading to NI-2?)

They say no changes on their end. The CO switch is a DMS100 (not GTD5
which I think will only do NI-2).

> I've seen one recently, but I don't recall where it was! There must also
> be Q.931 docs available for free somewhere?

I found what looked like OCR'ed ccitt/itu manuals but they are minus
diagrams. I broke down and bought them online from the ITU. You can
down load in postscript or MS word formats. www.itu.ch

I used a combination of Andre Beck's (beck@ibh-dd.de) very useful
dtrace program and my own manual annotations based on the q.931 doc
to produce the following. I've also sent this to GTE for their
analysis. I ignored all the layer 2 stuff.

PRI-XMIT-2/2: 25 octets @ B05B00E4      ;layer 3
  [0000]: 08 02 04 5C 05 04 02 88 90 18 04 E1 80 83 17 70
    08          <proto DSS1>
    02 04 5C    <callref caller 045c>
    05          <msgtype SETUP>
    04          <Bearer Capability,
    02          length 2,
    88          ccitt, cap Unrestricted digital,
    90          mode circuit, rate 64 kbps>
    18          <Channel ident,
    04          length 4,
    E1          int identified, PRI/other, preferred, not D chan, chan follows
    80          int id 00,
    83          ccitt, chan follows, B channel units,
    17          channel 0x17 = 23>
    70          <Called party number,
  [0010]: 08 A1 3x 3x 3x 3x 3x 3x 3x

    08          length 8,
    A1          type National, plan ISDN (E.164),
    3x 3x 3x 3x 3x 3x 3x        # xxxxxxx

PRI-RCV-2: 4 octets @ B05AFB00          ;layer 2
  [0000]: 00 01 01 56
PRI-RCV-2: 13 octets @ B05AFCA0         ;layer 2 + layer 3
  [0000]: 02 01 F8 56 08 02 84 5C 5A 08 02 82 AC
    08          <proto DSS1>
    02 84 5C    <callref callee 045c>
    5A          <msgtype RELEASE COMPLETE>
    08          <Cause,
    02          length 2,
    82          loc LN,
    AC          code 2c (44)>

The call setup looks fine to me but I haven't looked at one before we
started having problems so I have no baseline. Any advice would be
greatly appreciated!

---
Brian K. Uechi                 Email: brianu@lava.net
Technical Support Engineer     Phone: 808-545-5282
LavaNet, Inc.                  FAX  : 808-545-7020

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