[Freeswitch-users] [SOLVED] Re: UK ISDN outgoing CLI

[John]

This has been solved.  BT Openreach identified an issue with the 
exchange configuration that was forcing the lead number to be used as 
the outgoing caller id irrespective of the number from our FS box.  Many 
thanks to those who have offered helpful suggestions; it has allowed me 
to eliminate all alternatives and, ultimately, to articulate the fault 
in terms of non-compliance with Q951.3.

Summary of solution:

    Outgoing NPI: ISDN
    Outgoing TON: national
    Outgoing number format: 10 digit (ie strip leading 0)


Fault report that finally got results (real numbers have been substituted):

    For outgoing calls, SNDDI numbers (654321 or 654322) presented in
    the Calling Number Information Element of the Q931 SETUP packet with
    the screening indicator set to 'user-provided, verified and passed'
    are being overwritten by the BT exchange to the default number
    (654320) with the screening indicator set to 'network provided'. 
    This is contrary to Q951.3 which requires properly constituted
    Calling Numbers to be passed [irrespective of the CLIP supplementary
    service being provided].  The fault can be replicated by dialling
    654320 or 654322 from 654321.  The Caller ID passed should be
    1234654321 but instead is 1234654320.

Helpful diagnosis tools/hints:

    * Anecdotes from former BT engineers suggest that testing CLI with
      mobile phones is bad practice; mobile phone companies pick up some
      strange signalling.  I am not sure that this isn't just folklore
      or due to number-matching algorithms in the handset, but I chose
      to use my home analogue landline for testing.
    * Making calls back to the same set of lines means that you can see
      the full signalling for both outgoing and terminating legs, and
      the only thing in the way is the local exchange.
    * wanpipemon allows Sangoma board users to capture the D-channel
      signalling and then view/process using wireshark/tshark.  This is
      a game-changer.  Syntax is:

      wanpipemon -i w1g1 -pcap -pcap_file isdn.pcap -prot ISDN -full-systime -c  trd

      Replace w1g1 with the wanpipe device name, and the output will go
      to isdn.pcap.  You will need to run one capture for each BRI line
      you have (eg w2g1, w3g1 etc and to isdn1.pcap, isdn2.pcap, etc).

I hope to put something somewhere on the Wiki with this information when 
I get a spare moment (currently scheduled for Jan 2034).

Thanks again to all those who have helped resolve this.

John

On 13/07/11 21:16, John wrote:
> Thanks, Gavin. That would be really useful.
>
> John
>
> On 08/07/11 19:51, Gavin Henry wrote:
>> Hi John,
>>
>> We set this up for a customer using a Sangoma card and FusionPBX not
>> long ago. I can dig out the config next week when back in the office.
>> It's for ISDN30e but should help.
>>
>> Thanks.
>>
>> On 7/7/11, John<freeswitch at earthspike.net>   wrote:
>>> Jan,
>>>
>>> I have tried every combination of unknown, national and international
>>> with every combination of number length.  I have also confirmed that by
>>> using wanpipemon to capture the D-channel messages.  When I went through
>>> them with Wireshark and compared them with Q.931, everything was being
>>> set correctly by the Sangoma card/drivers.  I am at the point now where
>>> I need someone who has worked with BT ISDN switches to tell me what they
>>> can accept.  It seems that this is a national secret over here, or
>>> instead that they can accept almost anything and my lines have been
>>> configured to override the outgoing calling number with the base
>>> number.  Either way, the only way in which I think I am now going to get
>>> a result is by booking a fault.  Your helpful comment about modern
>>> switches being able to work this out also confirms that I am probably
>>> not looking at a Q.931 formatting error on my part, but on a blockage in
>>> the exchange.  I don't have a problem with the called number, for example.
>>>
>>> John
>>>
>>> On 07/07/11 23:09, Jan Berger wrote:
>>>> I must admit I don't remember what CLIP and CLOP is -- and my Q.931
>>>> experience is getting a bit rusty...
>>>>
>>>> Can you get a snoop of L3 out and in so I can see what you send and
>>>> what the switch responds back?
>>>>
>>>> I prefer to use Called and Calling -- The numbers contain a few bits
>>>> that tell what number this is. The most common are unknown, national
>>>> and international. These bits must match the actual number you send.
>>>> The 10 digit number is a unknown, the 11 digit is a national.
>>>> International start with 00 nn
>>>>
>>>> On top of that you will face that modern switches are quite capable
>>>> and able to configure whatever behaviour they want per line with
>>>> regards to called/calling -- so you need to find out exactly what the
>>>> switch expect on both called and caller for outgoing to behave as you
>>>> want.
>>>>
>>>> /Jan
>>>>
>>>>>> On our PRI systems we are sending 10 digits (2071231234), and on the
>>>>>> BRI system we are sending 11 digits (02071231234).
>>>>>>
>
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