Subject: [Simple] Real Time Text Discussion

From: Ben Campbell <[email-masked]>
Date: Wed, 17 Nov 2010 14:50:49 -0600

(as chair)

While interesting in general, I think the discussion on real-time text has wandered off into areas best discussed in ETSI or other fora. Please try to constrain the discussion to technical arguments about whether the IETF should or should not change the liaison response. I don't mean to pick on anyone in particular, and I fully admit there has been some ueful technical content to the discussion. But the IETF can't really help on questions of product availability, whether the service should be limited to only the hearing impaired, etc.

For reference, the initial liaison response is available at https://datatracker.ietf.org/documents/LIAISON/file1119.txt , and the liaison itself at https://datatracker.ietf.org/documents/LIAISON/file1085.doc . Be advised that the second link points directly to a downloadable MS Word document.

Thanks!

Ben.

---

From: Gunnar Hellstrom <[email-masked]>
Date: Thu, 18 Nov 2010 07:58:01 +0100

Ben,
Thanks for the reminder to keep the topic relevant for IETF.

I have not seen any request to change the liaison response, but if that
thought would appear, I want the following to be remembered. We have before
just been talking about heavy load on SIP servers, but not put other than
bandwidth figures to the arguments. The arguments get even more clear when
dressed in figures.

1. An intensive SIP real-time text call based on RFC 4103 for the text
medium causes a load on the SIP server of about 2 SIP protocol messages per
minute, equal to a voice VoIP call. (Assuming a mean length of 7 minutes )

2. An intensive SIP real-time text call based on SIP Message sent at 300 ms
interval can cause a load on the SIP server of about 720 SIP protocol
messages per minute. In reality there are always some pauses, so, say 600
protocol messages per minute as a realistic figure.

3. Allowing one call to consume as much resources in SIP servers as 300
other calls is clearly not recommendable.

4. IETF makes a lot of efforts to move away load from the SIP servers.
-MSRP messaging during the dialog following the media path was created to
replace SIP Message loading the central SIP server.
-RTCP based media control that follows the media path is now strongly
recommended instead of SIP INFO based media control that loads the SIP
servers.
-DTMF transmission in the media path through RFC 4733 is strongly
recommended instead of SIP INFO based DTMF transmission that loads the SIP
servers..
Real-time text is already from the beginning defined to use the media path
in RFC 4103. It would be against all the efforts from IETF for reduced load
on SIP servers, if the liaison response was modified to recommend a variant
of real-time text transmission to load the SIP Servers as much as 300 other
calls.

/Gunnar
==========================================================================

2010/11/17 Ben Campbell <[email-masked]>

> (as chair)
>
> While interesting in general, I think the discussion on real-time text has
> wandered off into areas best discussed in ETSI or other fora. Please try to
> constrain the discussion to technical arguments about whether the IETF
> should or should not change the liaison response. I don't mean to pick on
> anyone in particular, and I fully admit there has been some ueful technical
> content to the discussion. But the IETF can't really help on questions of
> product availability, whether the service should be limited to only the
> hearing impaired, etc.
>
> For reference, the initial liaison response is available at
> https://datatracker.ietf.org/documents/LIAISON/file1119.txt , and the
> liaison itself at
> https://datatracker.ietf.org/documents/LIAISON/file1085.doc . Be advised
> that the second link points directly to a downloadable MS Word document.
>
> Thanks!
>
> Ben.
> _______________________________________________
> Simple mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/simple
>