Subject: [Sipping] I-D Action:draft-ietf-sipping-service-examples-15.txt

From: [email-masked]
Date: Fri, 11 Jul 2008 11:30:01 -0700 (PDT)

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           : Session Initiation Protocol Service Examples
	Author(s)       : A. Johnston, et al.
	Filename        : draft-ietf-sipping-service-examples-15.txt
	Pages           : 167
	Date            : 2008-07-11

This document gives examples of Session Initiation Protocol (SIP)
services.  This covers most features offered in so-called IP Centrex
offerings from local exchange carriers and PBX (Private Branch
Exchange) features.  Most of the services shown in this document are
implemented in the SIP User Agents, although some require the
assistance of a SIP Proxy.  Some require some extensions to SIP
including the REFER, SUBSCRIBE, and NOTIFY methods and the Replaces
and Join header fields.  These features are not intended to be an
exhaustive set, but rather show implementations of common features
likely to be implemented on SIP IP telephones in a business
environment.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-sipping-service-examples-15.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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Internet-Draft.
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---

From: "Hutton, Andrew" <[email-masked]>
Date: Tue, 15 Jul 2008 09:24:05 +0100

This new draft still includes the following text in section 2.1 (Call
Hold).

"However, a UA that places the other party on hold will generally also
stop sending media, resulting in no media exchange between the UAs.
Older UAs may set the connection address to 0.0.0.0 when initiating
hold.  However, this behavior has been deprecated in favor of using the
a=sendonly SDP attribute."

The problem with this statement it indicates that a UA that stops
sending media when placing a call on hold should use the a=sendonly SDP
attribute which is incorrect. If a UA does not wish to send or receive
media then it should use the a=inactive attribute. A UA can use
a=sendonly for call hold but not in the case when it stops sending
media. I would really like to see the draft updated to fix this and
state that a=inactive is the attribute to use when the UA stops sending
media.

Regards
Andy

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of [email-masked]
Sent: 11 July 2008 19:30
To: [email-masked]
Cc: [email-masked]
Subject: [Sipping] I-D Action:draft-ietf-sipping-service-examples-15.txt

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.

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

---

From: Paul Kyzivat <[email-masked]>
Date: Tue, 15 Jul 2008 11:40:08 -0400

I agree with Andy here. A lot of people seem to think that you must use 
sendonly for hold - that inactive is inappropriate. But that is silly. 
Of course if you really want to you can negotiate sendonly and then not 
send anything. But IMO that shouldn't be held out as best practice. 
Doing so encourages people to build UAs that don't work when offered 
a=inactive.

	Thanks,
	Paul

---

From: Alan Johnston <[email-masked]>
Date: Tue, 15 Jul 2008 10:44:36 -0500

I can fix in Author's 48 hours as this should be the last version before 
protocol action.

Thanks,
Alan

Paul Kyzivat wrote:
> I agree with Andy here. A lot of people seem to think that you must 
> use sendonly for hold - that inactive is inappropriate. But that is 
> silly. Of course if you really want to you can negotiate sendonly and 
> then not send anything. But IMO that shouldn't be held out as best 
> practice. Doing so encourages people to build UAs that don't work when 
> offered a=inactive.
>
>     Thanks,
>     Paul
>
> Hutton, Andrew wrote:
>>

---

From: Paul Kyzivat <[email-masked]>
Date: Tue, 15 Jul 2008 11:56:35 -0400

sounds good!

	Thanks,
	Paul