SV8100 SIP re-invite gets "488 Not Acceptable Here", call is dropped

[bigdave1980]

Hello all,

We have deployed many NEC SV8100 systems and have had very few issues with them but we have one particular customer who has reported to us that they are seemingly unable to call certain numbers outside of the hotel. They are using SIP. They can call these numbers from a mobile just fine, and I can call the same numbers from here in our office just fine, but if they try calling from their premises they hear one ring and then drops back to a busy tone. We've had the SIP provider investigate this and they have run a trace for me and came back with the following:

"Hi, Please see attached trace. Just after the call is answered, the B-party sends a re-INVITE which the customer's PBX rejects with a '488 - Not Acceptable Here'. They'll need to investigate why their phone system did this. Regards".

A screenshot of the trace is attached:

I've seen that this can be due to some kind of codec mismatch, but is there some workaround for this or something I can adjust within the SV8100 to rectify the problem, please? If there is more info that I need to provide, please let me know.

Any help is much appreciated,

Dave

 

[Ragnorak]

There is a difference between g711a and g711u (think uLaw and aLaw.) North America would typically expect g711u and you can see that the SDP offer right before the "488 Not Acceptable" is for g711a. 84-13-03 should allow you to change the g711 type the SV8100 uses but depending on where you are that might cause issues. You may simply be swapping which calls work and which calls fail. But that does seem to be the problem.

 

[sto933]

Looks like codecs have nothing to do with this problem. G711A in all SDP's.
Why B-party send INVITE after 200 OK? Looks like it's copied from the original call. At least "From" header is the same. Flow chart is not enough to identify the problem.