Subject: [Sipping] I-D Action:draft-ietf-sipping-service-identification-01.txt

From: [email-masked]
Date: Sun, 24 Feb 2008 21:00:01 -0800 (PST)

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Session Initiation Proposal Investigation Working Group of the IETF.

	Title           : Identification of Communications Services in the Session Initiation Protocol (SIP)
	Author(s)       : J. Rosenberg
	Filename        : draft-ietf-sipping-service-identification-01.txt
	Pages           : 19
	Date            : 2008-02-24

This document considers the problem of service identification in the
Session Initiation Protocol (SIP).  Service identification is the
process of determining the user-level use case that is driving the
signaling being utilized by the user agent.  This document discusses
the uses of service identification, and outlines several
architectural principles behind the process.  It identifies several
perils associated with service identification, including fraud,
interoperability failures and stifling of innovation.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-sipping-service-identification-01.txt

To remove yourself from the I-D Announcement list, send a message to
[email-masked] with the word unsubscribe in the body of 
the message.
You can also visit https://www1.ietf.org/mailman/listinfo/I-D-announce
to change your subscription settings.

Internet-Drafts are also available by anonymous FTP. Login with the 
username "anonymous" and a password of your e-mail address. After 
logging in, type "cd internet-drafts" and then
	"get draft-ietf-sipping-service-identification-01.txt".

A list of Internet-Drafts directories can be found in
http://www.ietf.org/shadow.html
or ftp://ftp.ietf.org/ietf/1shadow-sites.txt

Internet-Drafts can also be obtained by e-mail.

Send a message to:
	[email-masked].
In the body type:
	"FILE /internet-drafts/draft-ietf-sipping-service-identification-01.txt".

NOTE:   The mail server at ietf.org can return the document in
	MIME-encoded form by using the "mpack" utility.  To use this
	feature, insert the command "ENCODING mime" before the "FILE"
	command.  To decode the response(s), you will need "munpack" or
	a MIME-compliant mail reader.  Different MIME-compliant mail readers
	exhibit different behavior, especially when dealing with
	"multipart" MIME messages (i.e. documents which have been split
	up into multiple messages), so check your local documentation on
	how to manipulate these messages.

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the
Internet-Draft.
_______________________________________________
Sipping mailing list  http://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: "Christer Holmberg" <[email-masked]>
Date: Tue, 26 Feb 2008 15:36:59 +0100

Hi,

To progress the work in a constructive way I have some comments on
things which I still think are missing from the draft.

Q1:
---

About dispatching to the approriate application, it is assumed that the
MSRP content etc is going to indicate e.g. what game you want to use
etc.

But, one use-case I've mentioned earlier, is how to distinguish between
a plain VoIP call and a VoIP call with specific application logic.

Another use-case is when you have multiple games which are controlled
using simple DTMF, ie there is no MSRP etc.

Q2:
---

Related to the previous comment, the draft says "look at the SDP and
you'll find the correct application". But, the draft does not cover the
case where the SDP you are looking at does not contain all the
information I may want to use during the session. For example, I may
start with voice, but I want to reach an application which allows me to
later add e.g. video, messaging - and certain application logic
associated to those.

Q3:
---

The draft focuses very much on how the receiving terminal is able to
dispatch an incoming message to the approriate application, but one
thing which the service id is used for is for finding an appropriate
terminal in the first place, ie forking. In this case it is not about
finding the correct application inside the terminal, or to figure out
what the calling party wants to do, but to find a terminal which
supports a number of capabilities in the first place. Some of these
capabilites can be registered using feature tags, e.g. whether the
terminal supports audio, video. But, a service "profile" can contain
much more than that: supported codecs, supported transport mechanisms,
supported security mechanisms, supported application logic (games,
supplementary services etc etc etc) etc etc etc. So, instead of
registering all those things separately, a profile service
identification is used instead. That does NOT prevent requests from
users that do not upport it to reach those terminals - it's all about
how the Accept-Contact header in such requests look like.

Regards,

Christer

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of 
> [email-masked]
> Sent: 25. helmikuuta 2008 7:00
> To: [email-masked]
> Cc: [email-masked]
> Subject: [Sipping] 
> I-DAction:draft-ietf-sipping-service-identification-01.txt
> 
> 	Title           : Identification of Communications 
> Services in the Session Initiation Protocol (SIP)
> 	Author(s)       : J. Rosenberg
> 	Filename        : 
> draft-ietf-sipping-service-identification-01.txt
> 	Pages           : 19
> 	Date            : 2008-02-24
> 
> This document considers the problem of service identification 
> in the Session Initiation Protocol (SIP).  Service 
> identification is the process of determining the user-level 
> use case that is driving the signaling being utilized by the 
> user agent.  This document discusses the uses of service 
> identification, and outlines several architectural principles 
> behind the process.  It identifies several perils associated 
> with service identification, including fraud, 
> To remove yourself from the I-D Announcement list, send a 
> message to [email-masked] with the word 
> unsubscribe in the body of the message.
> Internet-Drafts are also available by anonymous FTP. Login 
> with the username "anonymous" and a password of your e-mail 
> address. After logging in, type "cd internet-drafts" and then
> http://www.ietf.org/shadow.html or 
> ftp://ftp.ietf.org/ietf/1shadow-sites.txt
> 
> 	"FILE 
> /internet-drafts/draft-ietf-sipping-service-identification-01.txt".
> 
> Below is the data which will enable a MIME compliant mail 
> reader implementation to automatically retrieve the ASCII 
> version of the Internet-Draft.
>