Trunk cuts off starting 00 at transfer

[mdn_united]

hi Alcatel Gurus!

We have a Alcatel OXE, Release 11.0.1 and a problem with transfering calls via the OXE to a AudioCodes SIP Gateway.
The route of a call is like this: PSTN ->(S2M)-> OXE ->(S2M)-> AudioCodes ->(SIP)-> Lync

Calls are coming through and are going out. This works perfectly!
The only problem is, that the caller ID is not displayed correctly.
For example: A call from Germany should be shown like this: 0049634634364627
But the AudioCodes only gets: 49634634364627
I assume that the trunk is cutting off the 00 at the beginning of the number.
But we didn't configure the trunk to cut off numbers. "No. of digits unused (ISDN)" is set to "0" and "Numbers to be Added" is empty.

Does someone have an idea why the 00 in the beginning are missing?

I appreciate your help!

[vad]

1) You have received from PSTN calling number - check with t3 trace
2) You have displayed number (after external callback translation) - may be OXE add 00 in external callback translation table.
3) OXE send SETUP to AudioCodes - check with t3 trace

May be you will have answer (or give us initial data).

[mdn_united]

Hi Vad,
thank you for your hints!!

Playing around with the external callback translation wasn't working at all.

Then I tried the t3 traces.
Here is what I got on the trunk from the OXE to AudioCodes: (number masked with xxxx)
(This was a call from a mobile phone in Germany to the PBX - also located in Germany)

Code: Select all

 ______________________________________________________________________________
| (782513:000002) 6739: Send_IO1 (link-nbr=1, sapi=0, tei=0) :
| long: 54  desti: 0  source: 15  cryst: 1  cpl: 0  us: 8  term: 0  type a5
| tei: 0  <<<<  message sent : SETUP [05]    Call ref :  01 da
|______________________________________________________________________________
|
| IE:[04] BEARER_CAPABILITY (l=3) 80 90 a3
| IE:[18] CHANNEL (l=3)  a9 83 97 -> T2 : B channel 23 exclusive
| IE:[6c] CALLING_NUMBER (l=12)  ->  21  81  Num : 160702xxxx
| IE:[70] CALLED_NUMBER (l=5)  ->  a1  Num : xxxx
| IE:[7d] HLC (l=2) 91 81
| [a1] Sending complete
|______________________________________________________________________________

Next I tried to catch the incoming call on the trunk from the PSTN to OXE. (number masked with xxxx)
(This was a call from a mobile phone in Germany to the PBX - also located in Germany)
It seems that the OXE is cutting off zeros at the beginning of the number.

Code: Select all

 ______________________________________________________________________________
| (784180:000002) Concatenated-Physical-Event :
| long: 59  desti: 0  source: 0  cryst: 1  cpl: 10  us: 0  term: 0  type a5
| tei: 0  >>>>  message received : SETUP [05]    Call ref :  46 18
|                               SENDING COMPLETE
|______________________________________________________________________________
|
| IE:[04] BEARER_CAPABILITY (l=3) 80 90 a3
| IE:[18] CHANNEL (l=3)  a9 83 9e -> T2 : B channel 30 exclusive
| IE:[6c] CALLING_NUMBER (l=12)  ->  21  83  Num : 160702xxxx
| IE:[70] CALLED_NUMBER (l=10)  ->  c1  Num : 91374xxxx
| IE:[7d] HLC (l=2) 91 81
|______________________________________________________________________________

My final trace was a call from France (contry code +33) to the OXE in Germany. (number masked with xxxx)
I made the trace on the trunk from PSTN to OXE.
Again, ALL zeros are removed from the calling number

Code: Select all

______________________________________________________________________________
| (786676:000002) Concatenated-Physical-Event :
| long: 75  desti: 0  source: 0  cryst: 1  cpl: 10  us: 0  term: 0  type a5
| tei: 0  >>>>  message received : SETUP [05]    Call ref :  46 1c
|                               SENDING COMPLETE
|______________________________________________________________________________
|
| IE:[04] BEARER_CAPABILITY (l=3) 90 90 a3
| IE:[18] CHANNEL (l=3)  a9 83 87 -> T2 : B channel 7 exclusive
| IE:[1e] PROGRESS_ID (l=2) 8a 81
| IE:[6c] CALLING_NUMBER (l=13)  ->  11  80  Num : 333885xxxxx
| IE:[6c] CALLING_NUMBER (l=13)  ->  11  83  Num : 333885xxxxx
| IE:[70] CALLED_NUMBER (l=10)  ->  c1  Num : 91374xxxx
|______________________________________________________________________________

Now I have 2 problems:
1. I can't tell from the number if it is a national or an international call. I would expect 0 for national and 00 for international calls at the beginning of the number. (If I could, I would manipulate the caller ID on the AudioCodes.)
2. I don't know why OXE seems to cut off ALL zeros, no mater how many they are or should be.


The strangest thing is, that the number is displayed correctly on any Alcatel device.
From what I tested and found out, the displayed number on Alcatel devices is manipulated via "external callback translation".
But it does not change the caller ID that is handed over to the next trunk - in my case the trunk to the AudioCodes.


Do you have any more ideas?

Greetings

[vad]

From your trace - OXE receive just calling number - 16xx...., 33x.... without 0 or 00 at the beginning.

If you see 016xx...., 0033xxx.... on OXE sets display - OXE add this digits 0 or 00. Usually via Translator/ ext. numbering plan/ ext. callback translation (for first digits or letter A,B,C - you delete some digits and/or add some TG seizure prefixes like 0 or 00).
From my point of view - better to send calling number without modification - PSTN, OXE, AudioCodes, Linc (f.e. 33xxxx....). And the last system - Linc - shall modify displayed number via dialing rules.

[alex]

First of all where you need "00" to be presented?

Second, "00" is not cut from CALLING PARTY NUMBER by any operator or OXE at all. It is not even transmitted to the trunk. E.g., in France, mainly preceeding 0 is a national call PREFIX and 00 is an international PREFIX, but PREFIX could be any digit or combination of digits in a PABX. "0" and "00" are not part of any number. OXE and PTT switches get numbering plan identifier (NPI) for call routing from CALLING PARTY NUMBER IE in SETUP message.

Code: Select all

CALLING_NUMBER (l=12)  ->  21  81  Num : 160702xxxx

Here it a national number calling(NPI=21), i.e. to call this number you must use national prefix, e.g. "0".

Code: Select all

 IE:[6c] CALLING_NUMBER (l=13)  ->  11  80  Num : 333885xxxxx

Here you see an international number is calling (NPI=11).

That means in your case there is no need to add anything in OXE as this information is always sent to AudioCodes in SETUP message.
As your AudioCodes is used as gateway it is better to use E.164 normalization for Lync users.

[mdn_united]

Hello Alex,

your post was also very helpful.

I found in the setup message (on AudioCodes) a difference between international and national calls:
... SrcNT=2 ... -> national caller
... SrcNT=1 ... -> international caller

BUT, I couldn't figure out a way to use this information to manipulate the caller ID.
I hope I'll find somewhere a forum for AudioCodes that is as good as this one here ...

[mdn_united]

Update:
I found the option "Add NPI and TON to Calling Number" in the config of the Mediant 1000. (Configuration -> VoIP -> GW an IP to IP -> Routing)
Then I configured "yes" to this option. Now an "11" (international) or "12" (national) is added in the beginning of the calling number and with that I can use number manipulation to give it the right format.

Thanks for your inspiring comments!