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?   

Cheers,
bob


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