Subject: [Sip] Remote-Party-Id extensibility

From: Flemming Andreasen <[email-masked]>
Date: Wed, 27 Feb 2002 21:41:37 -0500

Please read and comment quickly:

As you may know, the privacy-04 draft will contain an applicability
statement that points out the environments in which the draft may be
usable. Suffice it to say, that these environments do not include the
general Internet at large, but rather resemble service provider like
models with transitive trust relationships.

Presently, the Remote-Party-Id header field consists of a bunch of
parameters, each of which is extensible. The concern that has been
raised is, that by allowing for all this extensibility, we are opening
ourselves up to duplicating existing (and perhaps future and more
general) headers and also to go beyond the applicability statement. It
has therefore been suggested, that we remove all this extensibility from
Remote-Party-ID, except for the rpi-privacy parameter. In essence, we
would prevent the Remote-Party-Id header from containing any kind of
identity (or other) information not currently defined in the draft. As a
consequence of that, the Nature of Party indication provided in Appendix
A would be removed from the draft as well. Instead, the idea would be to
provide these as part of a tel-url.

Your prompt feedback on this would be appreciated.

Thanks

        Flemming

--
Flemming Andreasen
Cisco Systems

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---

From: "Mark Watson"<[email-masked]>
Date: Thu, 28 Feb 2002 13:11:20 -0000

Flemming, all,

My opinion is that 95% of the value of the Remote-Party-ID header is in this
extensibility.

The extensibility provides a general purpose platform for handling of
identity information which is subject to privacy restrictions (in the
applicable environment), because we can add new types of identity and be
sure that the privacy handling will be applied to these even if the actual
identity type is not recognised by downstream systems.

If you remove this extensibility, you might as well define separate headers
for each identity ('Private-Calling-Party:' etc.), with separate Require:
tags, and then any SLAs between Service Providers with respect to privacy
would have to list the headers that were guaranteed to be respected. Such
SLAs would need extension every time new identities were added.

As it stands, we need only include support of the 'privacy' tag in the SLAs.

I can promise you that the lack of such extensibility in the PSTN has be a
nightmare. It was predicated on the assumption that we know a priori that a
given set of identity parameters are sufficient for present and future
purposes - an assumption which has proved wrong time and time again.

I would also hope that the envisioned future privacy support for the pure
Internet environment could be as backwards-compatible with Remote-Party-ID
as possible cf Dean's ideas about signing the RPID etc. If we rule out
extensibility now, we tie our hands somewhat with regards to this future
solution.

I would prefer to have the extensibiity left as in privacy-02.

Regards,

Mark

> -----Original Message-----
> From: Flemming Andreasen [mailto:[email-masked]]
> Sent: 28 February 2002 02:42
> To: [email-masked]
> Subject: Remote-Party-Id extensibility 
> 
>