Subject: [AVT] Re: draft-ietf-avt-rtcphr-00.txt

From: "Fardid, Reza" <[email-masked]>
Date: Fri, 16 Mar 2007 17:52:44 -0700

Authors of RTCP HR Draft:

I appreciate it if you clarify the following points?

1.	What is the definition of "resolution" in the context of this
document?

            The one used in the context of IPPM is clock resolution, per
2330.

            A rough ITU-T equivalent is sampling period.

            Is it generation of more granular reports than RTCP XR?

2.	Is there any way to distinguish the reports for fax sent in
pass-through mode from those for voice calls?

3.	Is the Correlation Tag affected for SIP calls that go through
SBC's?

Regards,

Reza Fardid

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: "Alan Clark" <[email-masked]>
Date: Fri, 16 Mar 2007 21:21:32 -0500

Hi Reza
 
When we use the term "High Resolution" we are generally referring to some of
the counters and proportions being expressed to twice the resolution (in
binary) to allow low packet loss rates and small changes in metrics to be
more easily detected.  Hence HR does not imply measurement to a higher
resolution but reporting to a higher resolution.
 
The issue of fax vs voice is an interesting one.  We could easily add
modem/fax to the list of media types in secion 3.8.5.  Modem/fax performance
is more sensitive to packet loss distribution than voice (see
http://www.telchemy.com/reference/ITUSG12_COM12_D96.pdf).
 
I think the correlation tag should not be affected by SBC's as the aim of
this is to provide a consistent way to track calls despite IP address/ port
changes.
 
Regards
 
Alan

  _____  

From: Fardid, Reza [mailto:[email-masked]] 
Sent: Friday, March 16, 2007 7:53 PM
To: [email-masked]
Subject: [AVT] Re: draft-ietf-avt-rtcphr-00.txt

3.	Is the Correlation Tag affected for SIP calls that go through SBC's?

Regards,

Reza Fardid