Subject: Re: [Sip] [Enum] FW: I-D Action:draft-schwartz-sip-e164-ownership-00.txt

From: Paul Kyzivat <[email-masked]>
Date: Mon, 18 Feb 2008 17:26:44 -0500

Nice draft.

One thing this highlights is that even if we solve the identity problem 
for E.164 numbers in sip-sip cases, the identity problem will remain for 
the pstn-sip case.

The solutions for the sip-sip case will presumably require that somebody 
actually *know* the sender is the owner of the number. The GW in a 
pstn-sip call will in general not know that. In reality the callerid in 
pstn calls cannot be trusted, so a true assertion of it cannot be done 
with a pstn source. Yet from a practical perspective most will consider 
a pstn assertion of identity to be something they want to know about.

That suggests to me that a weaker form of assertion is needed in that 
case, and that for suitably smart phones different forms of callerid 
presentation be used in those cases, reflecting the degree of confidence 
in the value being presented.

	Thanks,
	Paul
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---

From: "Dan Wing" <[email-masked]>
Date: Tue, 19 Feb 2008 00:20:44 -0800

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On 
> Behalf Of Paul Kyzivat
> Sent: Monday, February 18, 2008 2:27 PM
> To: SIP IETF
> Subject: Re: [Sip] [Enum] FW: 
> I-DAction:draft-schwartz-sip-e164-ownership-00.txt
> 
> Nice draft.
> 

The PSTN's assertion of identity using CLID (which is the PSTN's
user-asserted identity) is as valuable as SIP's "From:" (which is 
SIP's user-asserted identity).

The PSTN's assertion of identity using ANI (which is the PSTN's
network-asserted identity) is as valuable as SIP's 
"P-Asserted-Identity:" (which is SIP's network-asserted 
identity).

A PSTN->SIP gateway would not want to, and MUST NOT, attempt to
provide a stronger assertion of identity because the PSTN itself
has very a weak identity model (transitive trust).

-d