Subject: [MMUSIC] I-D ACTION:draft-ietf-mmusic-media-loopback-02.txt

From: [email-masked]
Date: Tue, 08 Nov 2005 18:50:01 -0500

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Multiparty Multimedia Session Control Working Group of the IETF.

	Title		: An Extension to the Session Description 
                          Protocol (SDP) for Media Loopback
	Author(s)	: K. Hedayat, et al.
	Filename	: draft-ietf-mmusic-media-loopback-02.txt
	Pages		: 17
	Date		: 2005-11-8
	
The wide deployment of VoIP and Video over IP services has 
    introduced new challenges in managing and maintaining voice/video 
    quality, reliability, and overall performance.  In particular, 
    media delivery is an area that needs attention.  One method of 
    meeting these challenges is monitoring the media delivery 
    performance by looping media back to the transmitter.  This is 
    typically referred to as "active monitoring" of services.   Media 
    loopback is especially popular in ensuring the quality of transport 
    to the edge of a given VoIP or Video over IP service.  Today in 
    networks that deliver real-time media, short of running 'ping' and 
    'traceroute' to the edge, service providers are left without the 
    necessary tools to actively monitor, manage, and diagnose quality 
    issues with their service.  The extension defined herein adds new 
    SDP media attributes which enables establishment of media sessions 
    where the media is looped back to the transmitter. Such media 
    sessions will serve as monitoring and troubleshooting tools by 
    providing the means for measurement of more advanced VoIP and Video 
    Over IP performance metrics.

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From: Colin Perkins <[email-masked]>
Date: Thu, 24 Nov 2005 13:22:53 +0000

> http://www.ietf.org/internet-drafts/draft-ietf-mmusic-media- 

Some comments on this draft:

1) The description of how rtp-pkt-loopback interacts with normal RTP  
header processing should be expanded. The data is supposed to be re- 
encapsulated for transmission back to the source, but how that is  
done is not well-specified. Should the answering entity use the same  
payload format as the original, or should the data be transcoded or  
somehow encapsulated in a new stream of RTP packets? If the original  
format is used, how is packet loss handled (what if the payload  
format is aware of sequence numbers)? If encapsulating, what is the  
encapsulation format? How are path-MTU limitations handled?

2) How is congestion on the reverse path handled?

3) The security considerations should discuss how to avoid packet  
bombing an unsuspecting third party. The draft states that  
authentication is needed, but I think it needs to provide more  
details (e.g. give an example of what sort of authentication can be  
used; how it prevent the problem).

Colin

---

From: "Gunnar Hellstrom" <[email-masked]>
Date: Mon, 28 Nov 2005 09:26:45 +0100

This draft looks very useful.

At the moment I just have one comment: Please do not forget the real-time
text medium. The three media of conversational communication are real-time
video, real-time text and real-time audio.
Real-time text has lagged behind but is getting momentum now, after
publication of RFC 4103, the new RTP payload for text conversation.

I think the mmusic group has accepted to keep in mind to include real-time
text
in the documents when appropriate. Here it is appropriate.

The method described in this draft is in fact media agnostic, so you only
need to adjust the abstract and the introduction to get the real-time text
medium included.

This is the abstract and Introduction after addition of ", Real-time-text"
in front of all occurrences of "and Video".
Also one case of "voice/video" is changed to "voice/real-time-text/video"

Note that the term text is not used without real-time.  This is because
other types of text that are not real-time are also increasingly being
transmitted in accompaniment with voice and video (e.g. IM and text
documents ), but
the loopback tests may not at all be relevant for such kinds of text
communication, while it definitely is for real-time text according to RFC
4103.

========Proposed modified Abstract====================================
Abstract

    The wide deployment of VoIP, Text and Video over IP services has
    introduced new challenges in managing and maintaining
    voice/real-time-text/video quality, reliability, and overall
    performance. In particular, media delivery is an area that needs
    attention. One method of meeting these challenges is monitoring the
    media delivery performance by looping media back to the transmitter.
    This is typically referred to as "active monitoring" of services.
    Media loopback is especially popular in ensuring the quality of
    transport to the edge of a given VoIP, Real-time-text or Video over IP
    service. Today in networks that deliver real-time media, short of
    running 'ping' and 'traceroute' to the edge, service providers are left
    without the necessary tools to actively monitor, manage, and diagnose
    quality issues with their service.  The extension defined herein adds
    new SDP media attributes which enables establishment of media sessions
    where the media is looped back to the transmitter. Such media
    sessions will serve as monitoring and troubleshooting tools by
    providing the means for measurement of more advanced VoIP, Real-time-
    text and Video over IP performance metrics.

 - - -Proposed modified introduction- - - - - - - - - - - -

 1. Introduction

    The overall quality, reliability, and performance of VoIP,
    Real-time-text and Video over IP services relies on the performance
    and quality of the media path. In order to assure the quality of
    the delivered media there is a need to monitor the performance of
    the media transport. One method of monitoring and managing the overall
    quality of VoIP, Real-time-text and Video over IP Services is through
    monitoring the quality of the media in an active session.  This type
    of "active monitoring" of services is a method of pro-actively managing
    the performance and quality of VoIP based services.

    The goal of active monitoring is to measure the media quality of a
    VoIP, Real-time-Text or Video over IP session.

===========================================

Regards
Gunnar
----------------------------------------------------------------------------
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Gunnar Hellstrom, Omnitor
[email-masked] <mailto:[email-masked]>
Mob: +46 708 204 288
Phone: +46 8 556 002 03
www.omnitor.se <http://www.omnitor.se>

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Sent: Wednesday, November 09, 2005 12:50 AM
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Subject: [MMUSIC] I-D ACTION:draft-ietf-mmusic-media-loopback-02.txt

A New Internet-Draft is available from the on-line Internet-Drafts
directories.
This draft is a work item of the Multiparty Multimedia Session Control
Working Group of the IETF.