> On Mon, 2009-03-02 at 13:37 -0500, Robert Joly wrote:
> > Hi,
> > I'm looking at ways to address the problem raised in
> > http://track.sipfoundry.org/browse/XECS-2233 whereby the unexpected 
> > caller ID is being presented by the gateway.
> > 
> > I had a look at that issue and I see that the sipXproxy correctly 
> > modifies the From: header to show the user-supplied Caller ID 
> > information however the message carries a 
> P-Asserted-Identity that is 
> > left untouched.  So for example, assuming that user 900 is 
> configured 
> > with [first|last name]= "V H" and caller ID "QANTOM", the following 
> > invite will be sent to the gateway:
> > 
> > INVITE sip:[email protected];user=phone SIP/2.0 [...]
> > From: "V H"<sip:[email protected]>;tag=735D31D1-2A20A4E8
> > [...]
> > P-Asserted-Identity:
> > "VH"<sip:[email protected];signature=499563DE0bc2e77a>
> > [...]
> > 
> > The gateway used for the test will show a caller Id of 900 
> when QANTOM 
> > was expected.
> > 
> > My guess is that the gateway used prefers 
> P-Asserted-Identity over the
> > >From header for the purposes of obtaining the caller ID 
> information.  
> > 
> > To get around this problem there are two potential 
> solutions but they 
> > each have their drawbacks.
> > 
> > Solution #1:  Change the Caller-Alias plug-in to apply the 
> caller ID 
> > to both the From the P-Asserted-Identity headers.  IMO, this option 
> > has 2 significant drawbacks:
> >    drawback a- as the request spirals inside the proxy, some 
> > redirectors may rely on P-Asserted-Identity to make some 
> decisions. If 
> > the sipXproxy changes the content of the P-Asserted-Identity when 
> > running the auth plug-in chain at the end of the first spiral, this 
> > may confuse some redirectors as they will see changing PAI between 
> > different passes in the spiral.
> >    drawback b- The identity being asserted in the 
> P-Asserted-Identity 
> > is the user's real identity - not its caller ID so changing 
> the PAI's 
> > user part to be the caller ID is likely not a good idea.
> > 
> > Solution #2: strip off the P-Asserted-Identity as the 
> request leaves 
> > sipXproxy after is has completed its spiraling.  While all the 
> > redirectors that rely on PAI as the request spirals will 
> continue to 
> > see it, any SIP endpoint that was expecting to get a request with a 
> > PAI from the sipXproxy will not find a PAI.  The only SIP endpoint 
> > that I know is like that is the sipXpage with the pending patch in 
> > XECS-2232 which I'm about to modify so that it stops relying on PAI.
> > 
> > 
> > Any comments? Does anybody know of other endpoints that rely on the
> > presence of PAI?   
> 
> What about alternative 3:
> 
> - Configure the gateway to use From and ignore PAI?
>
> What do we know about how this is done and how configurable it is?

I could not find a way to do this with the AudioCodes gateways that I
have to.  I also did a bit of googling - this does not appear to be a
typical configuration knob of gateways.

> We've got this doing the correct thing with our SIP Trunks 
> through sipXbridge...
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