Subject: RE: [Sipping] Use of media-feature tag "text" indraft-hellstrom-txtgwy-00.txt

From: Gunnar Hellström <[email-masked]>
Date: Fri, 30 Nov 2007 22:28:23 +0100

Stuart,
Thanks for your view.

Then, I suggest that a media feature tag "real-time-text" is included in the
draft 
http://www.ietf.org/internet-drafts/draft-hellstrom-text-turntaking-00.txt

With a definition that tells about the good flow of text.

The whole draft needs to change name also.

I hope the inclusion in the same draft does not mislead people to think that
real-time text has any eternal connection with the functionally limited
variants of text communication discussed in that draft. 

The new parameter can be combined with the turntaking ones into one
parameter with a value.
This is an idea for discussion about how it can be defined. Do you think
this would be suitable or shall we have two separate tags, one for
real-time-text and one for turntaking-requirements?

Possible change for discussion:
----------------------------------------------------------------------
   This specification defines a Media Feature tag 'real-time-text'.
   Its formatting in SIP headers is described in the following:

   Media Feature Tag name: sip.real-time-text

   ASN.1 Identifier: y.y.

   Summary of the media feature indicated by this tag: The
sip.real-time-text
   media feature tag indicates whether a communications
   device can handle the real-time text medium and if it
   can handle the text and audio media simultaneously
   in its user interface or towards attached devices, or if limitations
   must be applied by users who communicate with the device.

   Values appropriate for use with this feature tag: Token with an
   equality relationship.

   Defined values are:

   full-simultaneity:  The device can handle real-time text simultaneously
in both
      directions and if it supports audio, it can also be handled
      simultaneously. (default)

   unspecified-turntaking:  The device requires some ordered turn-taking to
take
      place.  It is not specified how strict this turntaking must be,
      and it is left to the users to figure out what level of turntaking
      signaling is needed.

   soft-turntaking:  The device can handle simultaneous transmission of text
in
      both directions, but there is a risk that the display is made in
      one window so that it requires "soft" turntaking indications in
      order to get a readable display.  Simultaneous transmission can be
      used for interruptions and alerting.  If audio is supported, it is
      handled alternating with text.

   strict-turntaking:  The device cannot handle real-time text transmission
in both
      directions in its user interface or towards attached devices.
      Strict turntaking must be applied by the users and is usually
      signalled by agreed turntaking indicators in the text medium.  If
      audio is supported, it shall only be used alternating with text.

   The feature tag is intended primarily for use in the following
   applications, protocols, services, or negotiation mechanisms: This
   feature tag is most useful in a communications application for
   describing the capabilities of a SIP device with some real-time-text
capability,
   with the values indicating limited simutaneity are intended for a PSTN
textphone gateway,
   connecting SIP devices with legacy textphones. The intention is both to
   support routing of the call and give an indication to the SIP device user
if
   turntaking must be applied.

   Examples of typical use: Choosing to communicate with a native, real-
   time text capable device rather than a legacy textphone behind a
   gateway, when a selection is possible.  Instruct the user of the SIP
   device about the need to apply turntaking habits as used with legacy
   textphones when the call is made through a gateway with that kind of
   device.

-------------------------------------------------------------------
Gunnar Hellström
Omnitor
[email-masked]
Tel: +46708204288
www.omnitor.se

-----Original Message-----
From: GOLDMAN, STUART O (STUART) [mailto:[email-masked]] 
Sent: Friday, November 30, 2007 7:01 PM
To: Gunnar Hellström; Sipping@Ietf. Org
Subject: RE: [Sipping] Use of media-feature tag "text"
indraft-hellstrom-txtgwy-00.txt 

Gunnar,

Since many people may not be knowledgeable about real time text, I agree
that just seeing "text" may lead them to believe that it is just text, so
having a separate and distinct tag for Real Time Text seems to be prudent.

Stuart Goldman
Alcatel-Lucent
[email-masked]
+1 602 493 8438
P please save a tree by not printing this e-mail.

-----Original Message-----
From: Gunnar Hellström [mailto:[email-masked]]
Sent: Friday, November 30, 2007 2:11 AM
To: 'Sipping@Ietf. Org'
Subject: [Sipping] Use of media-feature tag "text"
indraft-hellstrom-txtgwy-00.txt 

There is a draft about gateway procedures between SIP devices and PSTN in
www.ietf.org/internet-drafts/draft-hellstrom-txtgwy-00.txt

The draft recommends to use the Sip media-feature tag "text" ar an indicator
of capability for real-time text in order to facilitate routing and device
selection.

I have realized that the media-feature tag "text" may be not enough
specified to indicate the real-time variant of text communication. It could
probably be used to indicate general text capability for real-time, for
Messaging, and information provision.

Can we reserve the media-feature tag "text" to mean real-time text, or do we
need to register a new media-feature tag "real-time-text" to be explicit
enough for the routing and preference handling?

I would like to hear the thoughts of the sipping group on this. 
The draft will be very briefly announced in the coming sipping meeting. I
hope it will create enough interest to be regarded a WG item.

This relates also to another new draft at a similar state:
http://www.ietf.org/internet-drafts/draft-hellstrom-text-turntaking-00.txt

Gunnar   

-------------------------------------------------------------------
Gunnar Hellström
Omnitor
[email-masked]
Tel: +46708204288
www.omnitor.se

-----Original Message-----
From: Gunnar Hellström [mailto:[email-masked]]
Sent: Thursday, November 15, 2007 8:23 AM
To: 'Sipping@Ietf. Org'; Gonzalo. Camarillo@ericsson. com
Cc: Arnoud van Wijk
Subject: [Sipping] Agenda request for new draftdraft-hellstrom-txtgwy-00.txt

A draft has recently been submitted that relates to the Sipping group.

It is a proposed BCP for procedures for interworking between SIP UAs and
PSTN Textphones.
I would appreciate if it could get a short agenda point in the Sipping
Agenda. Arnoud van Wijk is prepared to present it.

And we look of course also forward to discussions in the list.

Gunnar
-------------------------------------------------------------------
Gunnar Hellström
Omnitor
[email-masked]
Tel: +46708204288
www.omnitor.se

Subject: I-D Action:draft-hellstrom-txtgwy-00.txt 

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title           : Real-time text interworking between PSTN and IP
networks
	Author(s)       : G. Hellstrom, et al.
	Filename        : draft-hellstrom-txtgwy-00.txt
	Pages           : 16
	Date            : 2007-11-10

IP networks can support real-time text communication.  SIP-based
real- time text is called Text-over-IP or ToIP.  PSTN networks support
real-time text using textphones (or TTYs).  When real-time text is supported
by different networks, gateways are needed to provide interoperability.
Real-time text capable gateways may also support real-time voice.

This specification describes procedures for interworking between ToIP and
PSTN textphones using a real-time text capable gateway (RTT gateway).  It
also describes ways to route calls to RTT gateways for several call
scenarios.

Procedures that support the phased introduction of RTT gateways and
procedures that support the invocation of text channels at any time during
the call are included.  Interworking of PSTN textphones that do not support
simultaneity of voice and text with IP User Agents that support simultaneous
voice and text is also described.

A URL for this Internet-Draft is:

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_______________________________________________
Sipping mailing list  https://www1.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