On Fri, Sep 12, 2008 at 9:03 AM, Scott Lawrence
<[EMAIL PROTECTED]> wrote:
>
> On Thu, 2008-09-11 at 18:05 -0400, M. Ranganathan wrote:
>
>> 1. Gateway  specifies a caller ID and an outbound call is routed
>> through the gateway. In this case, I expect that the proxy will place
>> a P-Asserted-Identity with the caller-Id as the address for the PAI as
>> well as a From header with the same information in it. That is, I
>> expect to see
>>
>> From: caller-id
>> P-Asserted-Identity: caller-id
>>
>> It would also be acceptable to just leave out the PAI header in this case.
>
>
>> 2. Gateway specifies anonymous calling and user makes a call routed
>> through the gateway. In this when the user places a trunk call through
>> the gateway, I want to see the following headers in the INVITE
>> received by sipxbridge
>>
>>  From: [EMAIL PROTECTED]
>>  P-Asserted-Identity: caller-Id
>
>
> I'd like to suggest some terminology for the purposes of this
> discussion, so that we are all sure that we are not agreeing
> without realizing it:
>
> real-caller-address
>   The actual AOR as configured by sipXconfig for the user
>   ([EMAIL PROTECTED]).  This is what normally appears in a From header
>   when a request is sent from a phone.
>
> caller-alias-address
>   This is what is configured, either for a specific user or for
>   a wildcard match, when a call is to be routed to a particular
>   gateway.  It is placed in the From header by the sipXproxy as
>   the request is being sent to the gateway (and the original
>   From header value is placed in the Route state information so
>   that it can be restored in messages bound for the original
>   caller).
>
> Note that neither of the above is 'caller-Id', so using the term
> 'caller-Id' is now out of bounds.
>
> Note also that sipXecs does not now have a feature that allows
> for an 'anonymous' call other than if you configure the address
> '[EMAIL PROTECTED]' (the standard for an 'anonymous' call in SIP)
> as a caller-alias-address.
>
> Phones may or may not ever put '[EMAIL PROTECTED]' in the From
> address, but at present if they do, the proxy will neither
> challenge the call to get a real identity for PAI nor do any
> caller-alias substitution of the caller address no matter where
> it is sent.
>
> Given the above, I can think of 4 cases.  For theses examples,
> treat '[EMAIL PROTECTED]' as a real-caller-address and '[EMAIL PROTECTED]'
> as a caller-alias-address:
>
>  1. Normal Call with No Alias
>
>     Phone sends '[EMAIL PROTECTED]' in From, proxy challenges and adds
>     '[EMAIL PROTECTED]' in PAI.  sipXbridge sees:
>
>       From: [EMAIL PROTECTED]
>       P-Asserted-Identity: [EMAIL PROTECTED]
>
>  2. Normal Call with Normal Alias
>
>     Phone sends '[EMAIL PROTECTED]' in From, proxy challenges and adds
>     '[EMAIL PROTECTED]' in PAI, then proxy replaces From with
>     '[EMAIL PROTECTED]', so sipXbridge sees:
>
>       From: [EMAIL PROTECTED]
>       P-Asserted-Identity: [EMAIL PROTECTED]
>
>  3. Normal Call with "anonymous" Alias
>
>     Phone sends '[EMAIL PROTECTED]' in From, proxy challenges and adds
>     '[EMAIL PROTECTED]' in PAI, then replaces From with
>     '[EMAIL PROTECTED]' (same as above, but the with the special
>     "anonymous" address), so sipXbridge sees:
>
>       From: [EMAIL PROTECTED]
>       P-Asserted-Identity: [EMAIL PROTECTED]


This is a problem. The problem is that [EMAIL PROTECTED] is not relevant to
the ITSP.  It is a user that is only relevant to sipx. Not to the
ITSP.

 Let  [EMAIL PROTECTED] be the actual "caller ID"  for
which we want an anonymous alias. What I want to see is :

From: [EMAIL PROTECTED]
P-Asserted-Identity: [EMAIL PROTECTED]


Note that I will not have any record of the actual PBX user when I see
a request like this. Therefore, if you prefer, I can handle this case
in Sipxbridge as I currently do. Which is to say, I will add the
P-Asserted-Identity in sipxbridge when I see From:[EMAIL PROTECTED] if
that makes life less complicated for the proxy server.


>
>  4. Anonymous Call from the phone:
>
>     Phone sends '[EMAIL PROTECTED]' in From, proxy will _not_
>     challenge, and will _not_ add PAI, so sipXbridge sees:
>
>       From: [EMAIL PROTECTED]
>
> So the questions are:
>
>  Which of the above cases do you believe is a problem?
>
>  Is there some capability that we need?

Not sure. If this effect can be achieved at present through a
configuration option, we add nothing. I know the effect I want to see.
 I am still learning how to configure sipx.

>
> Incidentally, in putting this together, one other issues suggests
> itself with respect to the existing caller alias feature.  At
> present, the caller alias feature only substitutes when the From
> address is in the domain of the proxy; any foriegn address is
> left unmodified.
>
>  A. In the existing implementation, there is already a note that
>     we should use an authenticated identity to decide whether or
>     not to do the substitution if we have one.  Now we do for
>     cases 1, 2, and 3 above, so we could change that.  This
>     would not change any of this discussion yet, but would be
>     more robust and secure than the current behavior.
>
>
>



-- 
M. Ranganathan
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