User Extension In Sip Invite From Field

[andyw]

I was just wondering whether anyone had any input on a SIP header issue.

 

We are using a Gamma SIP trunk on a SwyxWare 2015 R1 system, and struggling with some issues around number presentation.

 

The Swyx appears to send the users' four digit extension number as part of the SIP header on an outbound call.  This is listed both in the "Contact" and "From" fields, e.g. 1234@xxx.xxx.xxx.xxx.  This happens whether the user has a public number allocated to them or not.

 

Gamma are looking for a valid number to be in that field and therefore just present the CLI as the first public number associated with the trunk.  Any attempts to suppress the CLI in the "Number Signalling" field are ignored.  Using "Special Number Replacement" you can override the extension number by using 1234 -> 201234567 but that is not a practical solution.

 

We have used the same set up with Gamma under SwyxWare 2013, using the same provider profile, and in that case the user's public number appears in the header, as long as they have one allocated.

 

Does anyone have any suggestions as to why in this case the user's extension number is always presented?  Is this a 2015 vs 2013 issue?

 

Thanks

[andyw]

I have managed to work out what is causing this issue, so I thought I should post the information here in case someone comes across this thread.

 

The problem seems to occur only if and when you use a trunk selection prefix to make an outbound call on the trunk, which is how we were originally doing our testing.

 

- If the SIP trunk is configured with the highest routing priority, i.e. it the default trunk if 9 is the dial prefix, and a call is made to 9020xxxxx the Origination Number is correctly set to the public number allocated against the user in Swyx.

- If we allocate a trunk selection prefix of 8 to the trunk and then make a call to 8020xxxxxx the Origination Number is set to the extension number of the user in Swyx.  Swyx will then pass this extn@realm to the SIP trunk header, causing Gamma to ignore it entirely and use the provider specified, primary number which is allocated to the trunk instead; at which point Swyx has no control over the number presentation any more.

 

This is reproducible and has been tested on two different systems, both with SwyxWare 2015 and 2015 R2.

 

I can only assume it is a bug of some kind, because I don't see why it would be designed behaviour.  Does anyone know different?

[Virikas]

Did you already try

Trunk properties --> Number Signaling --> Always use originator's number

?

[andyw]

Virikas

 

Apologies, I did not see any notification for your reply to my original post.

 

Yes I have tried "Trunk properties --> Number Signaling --> Always use originator's number" and it seems to make no difference.  The trunk is currently set to "Use Originator's number if assigned to this trunk, otherwise suppress number"

 

I have just added new SIP trunks to a system that has never had SIP set up before and it behaves in exactly the same way again.  If you make a call over the trunk using 9, with the trunk set to highest priority, the SIP header shows <public number>@rxxx.xxx.xxx.xxx.  If you make the call over the same trunk, using a trunk selection prefix, the SIP header the from field shows <extn>@xxx.xxx.xxx.xxx instead of the public number.

 

Thanks