Subject: [Enum] SIP as SRS questions

From: Lawrence Conroy <[email-masked]>
Date: Thu, 7 Nov 2002 15:32:19 +0000

Hi folks,
   I've been trying to understand how SIP works as a Service Resolution Service.
As a core feature, SIP allows a user to register a number of different kinds of
URIs "behind" a single Address of Record. This is neat, as it looks like SIP is
the core of an ENUM SRS. BUT...I have some questions on the detailed 
mechanisms.

(i) The callee can decide what URIs they register. However, how does this SIP
subscriber specify the features/teleservices with which each of these URIs is
associated?

(ii) How does the caller specify the features/teleservices in which 
they are willing
to engage? (This is what we have in the past called their "services 
of interest").
I *think* that this involves SIP callerprefs (specifically feature-lists),
but am not sure.
Can anyone confirm that this is how the SIP feature/teleservice 
negotiation is done?

As a final plea, could we have a quick run-through of this at the ATL 
ENUM meeting -
it doesn't seem to be obvious from the drafts, and is a key issue, IMHO.

all the best,
   Lawrence
-- 
-----------------------------------------------------------------------
Roke Manor Research    : This information is provided "as is" and is not
<mailto:[email-masked]>: intended to create any contractual or legal
<tel:+441794833666>    : relationship.

_______________________________________________
enum mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/enum

---

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 07 Nov 2002 12:16:45 -0500

inline.

> subscriber specify the features/teleservices with which each of these 

Through the caller preferences specification:

http://www.ietf.org/internet-drafts/draft-ietf-sip-callerprefs-06.txt

which allows a UA to include capabilities and other information as part 
of its registration. For example, a UA can say "this UA does audio, 
video and supports these SIP methods".

> 
> (ii) How does the caller specify the features/teleservices in which they 
> are willing
> to engage? (This is what we have in the past called their "services of 
> interest").

Yes, but not just with caller prefs.

The caller can include explicit preferences, such as "route this request 
to the UA that supports audio and video and is a voicemail server". 
Caller prefs provides headers for doing that (Accept-Contact, 
Reject-Contact).

However, connecting a caller to a callee is a two party problem. Both 
participants have preferences. The caller might want an audio call, but 
the callee has preferences too - that they want audio calls to go to 
their cell phone. This is handled genreally through routing applications 
that run in the domain of the callee. THose can be supported through 
things like CPL, servlets, CGI and even more tradtitional APIs like JCC 
and Parlay, which would run ontop of SIP proxies. How the caller 
preferences and callee logic are combined is a matter of local policy.

hth,
Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com