Subject: RE: [Enum] Robert and Douglas' Protocols and Services draft...

From: Kevin McCandless <[email-masked]>
Date: Wed, 31 Oct 2001 11:27:03 -0800

Jonathan:

Help me here.  I thought that SDP was to be used for the multimedia session
and that the core part of SIP was making the initial Invite and setting up
the three way handshake.  Therefore, would I only need one SIP address ie
how to get a hold of me and then use SDP for the fun stuff ie IM?

Kevin

-----Original Message-----
From: Jonathan Rosenberg [mailto:[email-masked]]
Sent: Wednesday, October 31, 2001 12:15 PM
To: [email-masked]; [email-masked]
Cc: Michael Mealling
Subject: RE: [Enum] Robert and Douglas' Protocols and Services draft...

> -----Original Message-----
> From: Robert H. Walter [mailto:[email-masked]]
> Sent: Wednesday, October 31, 2001 12:46 PM
> To: [email-masked]
> Cc: Michael Mealling
> Subject: QRE: [Enum] Robert and Douglas' Protocols and 
> Services draft...
> 
> 
> Hi Michael,
> 
> Thank you for the feedback... Your suggestion of defining an IANA
> registry for both the protocols and services is excellent and we
> will incorporate this into the next revision of the draft.
> 
> You raise an interesting point regarding the use of SIP with IM.
> Will the SIP extension(s) proposed in the SIMPLE working group I-D
> "SIP Extensions for Instant Messaging" (draft-ietf-simple-im-01.txt)
> be absorbed into SIP or will a new extended SIP protocol (e.g. simple)
> be born?  If the latter is the case, I agree that it makes sense to
> specify SIMPLE as a resolution protocol.

First, let me answer the basic sip questions.

The cited IM draft will not be "absorbed" into SIP in the sense that it is
part of the new baseline specification, currently documented in
draft-ietf-sip-rfc2543bis-05.txt. It is an extension. However, just because
something is an extension to SIP doesn't mean that its a new service, per
se, in the enum sense of service. For example, the SIP extension for caller
preferences (draft-ietf-sip-caller-prefs) is an extension but surely not a
separate service as far as enum is concerned.

Note that there is a slippery slope here, as to what constitutes a new
service, and what does not. IM is a tricky thing. The SIMPLE group is
debating a session model, which would treat IM as a "media stream" alongside
voice and video. The draft you cite above describes the "paging" model,
where you simple send an IM out of the blue. The session model is very
interesting for ENUM. If I want to talk to someone, and I use a SIP INVITE
to set up that call, should there be a separate ENUM service tag for each
different type of media I want to use to communicate with? That is, do we
have E2VOICE and E2VIDEO in addition to E2IM? Interestinly, a call can start
with voice, and later add video. The ENUM resolution would only occur when
the call is initially setup with voice, and not when the video stream is
added. 

The same kind of things can happen for IM. If I set up a call with SIP,
using INVITE, and indicate an IM stream, does that mean that E2IM gets used?
What if the initial call setup has BOTH IM and voice streams? Which service
tag is used? If we don't look at the media streams to determine the service,
and always use E2TEL, say, that means that a page IM could go somewhere
different from a call that has an IM media stream. Is that what we want?

-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

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From: "Christian Huitema" <[email-masked]>
Date: Wed, 31 Oct 2001 14:04:51 -0800

Jonathan,

If you think about it, the main case for using enum is an IP based long
distance providers that receives a phone call because it is the
"selected provider" of the caller, and then looks for the appropriate
destination on the Internet. We are unlikely to get anything else than a
voice call in these situations.

-- Christian Huitema

> Sent: Wednesday, October 31, 2001 10:15 AM

---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 31 Oct 2001 19:50:34 -0500

> From: Christian Huitema [mailto:[email-masked]]
> Sent: Wednesday, October 31, 2001 5:05 PM
> To: Jonathan Rosenberg; [email-masked]; [email-masked]
> Cc: Michael Mealling

I agree this is the primary benefit of enum for voip. But, people appear to
want to use enum for other things. I just want to be sure that the lookup
procedure is well defined, deterministic, and repeatable. This means that I
need to have a clear and concise way of knowing which service tag to use,
and that is far from clear to me at this point.

-Jonathan R. 

---

---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 31 Oct 2001 19:50:34 -0500

> Sent: Wednesday, October 31, 2001 4:15 PM
> To: Jonathan Rosenberg; [email-masked]
> The proposed solution should be flexible enough to allow 
> multiple services
> to be associated with a single SIP address, as well as, 
> multiple services
> to be associated with multiple SIP addresses.  Consider the following
> examples:
> 
> 1.  A integrated SIP-based IM and voice system on a PC would 
> be specified
>     via a single address:
>  
>     sip+E2IM+E2TEL --> sip:[email-masked]
> 
> 2.  An IM service is associated with a desktop PC and the 
> voice service
>     is associated with an IP-Phone that is managed by a 
> service provider.
> 
>     sip+E2IM  --> sip:[email-masked]
>     sip+E2TEL --> sip:[email-masked]
> 
> How else could the service discovery be accomplished?

Bob, my point is that it is far from clear how an automata would determine
which service tag its looking for. That needs to be clearly specified, and
its not obvious to me that IM and presence, for example, should have a
separate service tag from "regular SIP".

-Jonathan R.

---

---

From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 31 Oct 2001 19:50:35 -0500

> From: Kevin McCandless [mailto:[email-masked]]
> Sent: Wednesday, October 31, 2001 2:27 PM
> To: 'Jonathan Rosenberg'
> Cc: Michael Mealling; [email-masked]; [email-masked]

This is the session model, yes. My point is that Robert has defined a E2IM
URI, and I was arguing that if IM is a stream, described by SDP, then its
not clear whether or not I would use this resolution service tag or the
E2TEL tag.

-Jonathan R.

---

---

From: Nathan Nelson <[email-masked]>
Date: Wed, 31 Oct 2001 20:45:19 -0500

The primary application for ENUM should be to allow carriers providing voice
services for small business and residential users to interact with medium to
large corporations.  ENUM should translate 800 or other customer service or
main corporate access numbers into ENUM addresses then transport call setup
and voice over ip.  This allows the corporations to save money and the
carriers to save money therefore passing saving on to the end consumer.

Long Distance should and most likely will go away, i.e. wireless LD.  ENUM
should not be looked upon to translate numbers to intermediary carriers like
LD companies.  ENUM should allow consumers to speak directly with providers
with as few middle men as possible.  This should be the goal.  

Translate a number to and IP addressable destination and allow the call to
complete.

Thx,
Nate Nelson
Senior Architect 
Cbeyond Communications    

-----Original Message-----
From: Jonathan Rosenberg [mailto:[email-masked]]
Sent: Wednesday, October 31, 2001 7:51 PM
To: Christian Huitema; Jonathan Rosenberg; [email-masked];
[email-masked]
Cc: Michael Mealling

-Jonathan R. 

---