Re: [Dart] I-D Action: draft-york-dart-dscp-rtp-00.txt

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Hi David,

thanks, your team created a well written draft. 

If a MediaStream is carried in a RTP session, the text may also explicitely say that 
(it says MediaStreamTrack == media flow, which is carried in an individual RTP 
packet stream)

Is the following correct:

UDP_5-tuple-+--transport protocol 1-----
            +--RTP session 1-----
            +--RTP session 2-----+---RTP_stream_2.1

This is impressive on first sight for a non-application expert. If the number of RTP (and other
transport) streams is high, I doubt that DiffServ is able to support more than rough 
differentiation. DiffServ is designed to aggregate traffic of similar requirements. Fine grained 
differentiation should be part of the application.

The question coming to my mind is, whether your team can add a statement how many AF classes are 
useful to carry different RTP sessions within one UDP flow. I'd be happier to live without a hen 
and egg problem (meaning app developers to wait for the transport guys to provide a set of 
defined classes and transport guys waiting for app developers to demand a number of defined 



-----Ursprüngliche Nachricht-----
Von: Dart [] Im Auftrag von Black, David
Gesendet: Samstag, 7. Juni 2014 03:05
Betreff: [Dart] FW: I-D Action: draft-york-dart-dscp-rtp-00.txt

On behalf of the author team, here's an initial -00 draft for consideration by the dart WG.  Please keep in mind that this is a -00 draft, so it really is a "draft".

I should be embarrassed that it appeared to take a public nudge from a past IETF Chair (Harald) to get this draft to appear, (Aside: if you'd like that ability, send your name to the NomCom this year - they're always looking for interested candidates for all positions), but the fact of the matter is that more than one of us had the experience of life being what happens while one is busy making other plans.

Comments and feedback are welcome and encouraged.

David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786        Mobile: +1 (978) 394-7754

-----Original Message-----
From: I-D-Announce [] On Behalf Of
Sent: Friday, June 06, 2014 8:49 PM
Subject: I-D Action: draft-york-dart-dscp-rtp-00.txt

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

        Title           : Differentiated Services (DiffServ) and Real-time Communication
        Authors         : Dan York
                          David Black
                          Cullen Jennings
                          Paul Jones
	Filename        : draft-york-dart-dscp-rtp-00.txt
	Pages           : 13
	Date            : 2014-06-06

   This document describes the interaction between Differentiated
   Services (DiffServ) network quality of service (QoS) functionality
   and real-time network communication, including communication based on
   the Real-time Transport Protocol (RTP).  DiffServ is based on network
   nodes applying different forwarding treatments to packets whose IP
   headers are marked with different DiffServ Code Points (DSCPs).  As a
   result, use of different DSCPs within a single traffic flow may cause
   transport protocol interactions (e.g., due to reordering).  In
   addition, DSCP markings may be changed or removed between the traffic
   source and destination.  This document covers the implications of
   these DiffServ aspects for real-time network communication, including

The IETF datatracker status page for this draft is:

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