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Subject: Re: [AVTCORE] I-D Action: draft-ietf-avtcore-srtp-vbr-audio-04.txt
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AVTCORE participants:

I'll be issuing a 2nd IETF LC for this soon calling out that the 
recommendations have been strengthened and
that the intended status is changed to Proposed Standard. Please verify 
that you are ok with these changes as
part of that LC.

RjS

On 12/30/11 5:16 PM, Colin Perkins wrote:
> On 30 Dec 2011, at 23:09, Internet-Drafts@ietf.org wrote:
>> A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Audio/Video Transport Core Maintenance Working Group of the IETF.
>>
>> 	Title           : Guidelines for the use of Variable Bit Rate Audio with Secure RTP
>> 	Author(s)       : Colin Perkins
>>                           Jean-Marc Valin
>> 	Filename        : draft-ietf-avtcore-srtp-vbr-audio-04.txt
>> 	Pages           : 7
>> 	Date            : 2011-12-30
>>
>>    This memo discusses potential security issues that arise when using
>>    variable bit rate audio with the secure RTP profile.  Guidelines to
>>    mitigate these issues are suggested.
>
> This version strengthens the recommendations in the light of review by the security area, and discussion in SAAG at IETF 82. This was heavily influenced by http://www.cs.unc.edu/~fabian/papers/foniks-oak11.pdf
>
> In the light of the changes, a new WG last call is likely required.
>
> Colin
>
>

From iesg-secretary@ietf.org  Mon Jan  9 09:17:36 2012
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Subject: [AVTCORE] 2nd Last Call: <draft-ietf-avtcore-srtp-vbr-audio-04.txt> (Guidelines	for the use of Variable Bit Rate Audio with Secure RTP) to	Proposed Standard
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The IESG has received a request from the Audio/Video Transport Core
Maintenance WG (avtcore) to consider the following document:
- 'Guidelines for the use of Variable Bit Rate Audio with Secure RTP'
  <draft-ietf-avtcore-srtp-vbr-audio-04.txt> as a Proposed Standard

This is a second IETF Last Call to verify the strengthening of recommendations as a result of
security area review during IESG evaluation, and a change of intended status from BCP to
Proposed Standard.

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2012-01-23. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


   This memo discusses potential security issues that arise when using
   variable bit rate audio with the secure RTP profile.  Guidelines to
   mitigate these issues are suggested.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-avtcore-srtp-vbr-audio/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-avtcore-srtp-vbr-audio/


No IPR declarations have been submitted directly on this I-D.



From jsaldana@unizar.es  Tue Jan 10 03:34:19 2012
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Subject: [AVTCORE] Proposal for updating TCRTP (RFC 4170)
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Hello all.

My name is Jose Saldana, from the University of Zaragoza, in Spain. I am =
new
here.

I would like to share with AVTCORE Work Group a proposal, in case it =
could
be considered interesting. The main idea is to update TCRTP. This is a =
"Best
current practice" RFC (http://datatracker.ietf.org/doc/rfc4170/) which =
was
developed in Audio/Video Transport working group in 2005-11. It =
"describes a
method to improve the bandwidth utilization of RTP streams over network
paths that carry multiple Real-time Transport Protocol (RTP) streams in
parallel between two endpoints, as in voice trunking. The method =
combines
standard protocols that provide compression, multiplexing, and tunneling
over a network path for the purpose of reducing the bandwidth used when
multiple RTP streams are carried over that path." (from the introduction =
of
RFC4170).


The scheme of TCRTP is:

  RTP/UDP/IP
     |
     |
   ECRTP (compressing layer). Compresses RTP/UDP/IP headers
     |
     |                   =20
    PPPMux (multiplexing layer). Includes a number of compressed packets
into a bigger one
     |
     |
   L2TP     (tunneling layer). Permits its use end-to-end
     |
     |
     IP


However, there exist many real-time flows that do not use RTP:

- Online "First Person Shooter" (FPS) games use UDP datagrams, and they =
are
one of the most "real-time" applications nowadays. Some examples: =
Counter
Strike, Halo, Quake, etc.[1].

- Online "Massively Multiplayer Online Role Playing Games" (MMORPG): =
They
use TCP, but can be considered "real-time", since the actions of the =
players
have to be transmitted very quickly to the server. It should be taken =
into
account that player vs player fights are one of the possible activities =
of
the game. Some examples: World of Warcraft (more than 10 million
subscribers) [2].

- TCP is also getting used for media delivery. For many reasons, such as
avoiding firewalls, the standard IP/ UDP/ RTP protocol stack is =
substituted
in many cases by IP/ TCP/ HTTP/ FLV [3].

- Another interesting scenario is satellite communication links.
Multiplexing small packets into one packet for transmission would =
improve
the efficiency. Satellite links would also find it useful to multiplex =
small
TCP packets into one packet =96 this could be especially interesting for
compressing TCP ACKs.


In our recent research activities, we have adapted TCRTP scheme for its =
use
when the traffic is not RTP. The idea is to substitute ECRTP by other
compression scheme which can be used for UDP or TCP headers. In 2006, =
the
IETF formed the Robust Header Compression (ROHC) working group which =
created
specifications for header compression over links for RTP, UDP and TCP.
These specifications were extended to compress headers over other =
networks.
For most RTP flows, ROHC is more bandwidth efficient than ECRTP, at the =
cost
of implementation complexity. It has a special care of context
synchronization, defining some states at the compressor and =
decompressor.
Once the effort for designing ROHC has been conducted, it is worth =
including
it in the compressing and multiplexing standard.


In a recent paper in Nov. issue of IEEE Communications Magazine, it was
shown that 30% of bandwidth saving can be achieved for 8 FPS different =
games
using IPv4. If IPv6 is used, savings can be up to 54% [4]. Another =
recent
study, which is still under review, has estimated 45% bandwidth saving =
for
World of Warcraft.


After talking to other researchers, including some of the authors of
RFC4170, the possible scheme of the proposal could be this one:


G.711.0 payload compression        TCP     UDP   UDP/RTP
                 |                    |      |      |
                 |                     \     |     /
                 |                       \   |   /
                 |               nothing or ROHC or ECRTP
                 |                           |
                  \                         /
                    \                     /
                multiplexing layer (other or PPPMUX)
                           |
                           |
               tunneling layer (other or GRE or L2TP)
                           |
                           |
                          IP


It should be more "open" than TCRTP. I mean, it could be "orthogonal" to
different protocols: different header compression algorithms could be =
used,
depending on the application and the scenario; also different =
multiplexing
and tunneling protocols could be included. Finally, we have also =
included
the G.711.0 "branch": it could be interesting to convert G.711 to =
G.711.0 (a
lossless encoding of G.711) and back, using a similar tunneling =
mechanism.
In a similar way to TCRTP, the G.711 to G.711.0 and vice versa =
conversion
does not involve SIP/SDP/RTSP signaling with the endpoints, since G.711 =
has
a fixed RTP payload number.

We have not written a draft. This is only the first idea, so we look =
forward
to hearing the opinion of the Working Group,


Thank you very much, and sorry for writing such a long message,

Jose Saldana
University of Zaragoza

______________

[1] Ratti, S.; Hariri, B.; Shirmohammadi, S., "A Survey of First-Person
Shooter Gaming Traffic on the Internet," Internet Computing, IEEE , =
vol.14,
no.5, pp.60-69, Sept.-Oct. 2010. URL:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5445069&isnum=
ber=3D556
2482

[2] P. Svoboda, W Karner and M. Rupp, =93Traffic Analysis and Modeling =
for
World of Warcraft,=94 ICC '07. IEEE International Conference on
Communications, pp.1612-1617, 24-28, Jun. 2007. URL:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D4288941&isnum=
ber=3D428
8671

[3] G. Marfia and M. Roccetti, =93TCP At Last: Reconsidering TCP=92s =
Role for
Wireless Entertainment Centers at Home,=94 IEEE Transactions on Consumer
Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. URL:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5681095&isnum=
ber=3D568
1060

[4] J. Saldana, J. Fern=E1ndez-Navajas, J. Ruiz-Mas, J. I. Aznar, E. =
Viruete
and  L. Casadesus, =93First Person Shooters: Can a Smarter Network Save
Bandwidth without Annoying the Players?,=94 IEEE Communications =
Magazine,
Consumer Communications and Networking Series, vol. 49, no. 11, pp. =
190-198,
Nov. 2011. URL:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D6069728&isnum=
ber=3D606
9696

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charset=3Diso-8859-1">
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14.02.5004.000">
<TITLE>Proposal for updating TCRTP (RFC 4170)</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/rtf format -->

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">Hello all.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">My name is Jose =
Saldana, from the University of Zaragoza, in Spain. I am new =
here.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">I would like to =
share with AVTCORE Work Group a proposal, in case it could be considered =
interesting. The main idea is to update TCRTP. This is a &quot;Best =
current practice&quot; RFC (<A =
HREF=3D"http://datatracker.ietf.org/doc/rfc4170/">http://datatracker.ietf=
.org/doc/rfc4170/</A>) which was developed in Audio/Video Transport =
working group in 2005-11. It &quot;describes a method to improve the =
bandwidth utilization of RTP streams over network paths that carry =
multiple Real-time Transport Protocol (RTP) streams in parallel between =
two endpoints, as in voice trunking. The method combines standard =
protocols that provide compression, multiplexing, and tunneling over a =
network path for the purpose of reducing the bandwidth used when =
multiple RTP streams are carried over that path.&quot; (from the =
introduction of RFC4170).</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">The scheme of =
TCRTP is:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Courier New">&nbsp; =
RTP/UDP/IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp; ECRTP (compressing layer). Compresses RTP/UDP/IP =
headers</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp; PPPMux (multiplexing layer). Includes a number =
of compressed packets into a bigger one</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp; L2TP&nbsp;&nbsp;&nbsp;&nbsp; (tunneling layer). =
Permits its use end-to-end</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp; IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">However, there =
exist many real-time flows that do not use RTP:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">- Online =
&quot;First Person Shooter&quot; (FPS) games use UDP datagrams, and they =
are one of the most &quot;real-time&quot; applications nowadays. Some =
examples: Counter Strike, Halo, Quake, etc.[1].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">- Online =
&quot;Massively Multiplayer Online Role Playing Games&quot; (MMORPG): =
They use TCP, but can be considered &quot;real-time&quot;, since the =
actions of the players have to be transmitted very quickly to the =
server. It should be taken into account that player vs player fights are =
one of the possible activities of the game. Some examples: World of =
Warcraft (more than 10 million subscribers) [2].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">- TCP is also =
getting used for media delivery. For many reasons, such as avoiding =
firewalls, the standard IP/ UDP/ RTP protocol stack is substituted in =
many cases by IP/ TCP/ HTTP/ FLV [3].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">- Another =
interesting scenario is satellite communication links. Multiplexing =
small packets into one packet for transmission would improve the =
efficiency. Satellite links would also find it useful to multiplex small =
TCP packets into one packet &#8211; this could be especially interesting =
for compressing TCP ACKs.</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">In our recent =
research activities, we have adapted TCRTP scheme for its use when the =
traffic is not RTP. The idea is to substitute ECRTP by other compression =
scheme which can be used for UDP or TCP headers. In 2006, the IETF =
formed the Robust Header Compression (ROHC) working group which created =
specifications for header compression over links for RTP, UDP and =
TCP.&nbsp; These specifications were extended to compress headers over =
other networks. For most RTP flows, ROHC is more bandwidth efficient =
than ECRTP, at the cost of implementation complexity. It has a special =
care of context synchronization, defining some states at the compressor =
and decompressor. Once the effort for designing ROHC has been conducted, =
it is worth including it in the compressing and multiplexing =
standard.</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">In a recent =
paper in Nov. issue of IEEE Communications Magazine, it was shown that =
30% of bandwidth saving can be achieved for 8 FPS different games using =
IPv4. If IPv6 is used, savings can be up to 54% [4]. Another recent =
study, which is still under review, has estimated 45% bandwidth saving =
for World of Warcraft.</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">After talking =
to other researchers, including some of the authors of RFC4170, the =
possible scheme of the proposal could be this one:</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Courier New">G.711.0 payload =
compression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
TCP&nbsp;&nbsp;&nbsp;&nbsp; UDP&nbsp;&nbsp; UDP/RTP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp; |&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp; nothing or ROHC or ECRTP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
/</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp; multiplexing layer (other or =
PPPMUX)</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp; tunneling layer (other or GRE or =
L2TP)</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Courier =
New">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n=
bsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp; IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">It should be =
more &quot;open&quot; than TCRTP. I mean, it could be =
&quot;orthogonal&quot; to different protocols: different header =
compression algorithms could be used, depending on the application and =
the scenario; also different multiplexing and tunneling protocols could =
be included. Finally, we have also included the G.711.0 =
&quot;branch&quot;: it could be interesting to convert G.711 to G.711.0 =
(a lossless encoding of G.711) and back, using a similar tunneling =
mechanism. In a similar way to TCRTP, the G.711 to G.711.0 and vice =
versa conversion does not involve SIP/SDP/RTSP signaling with the =
endpoints, since G.711 has a fixed RTP payload number.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">We have not =
written a draft. This is only the first idea, so we look forward to =
hearing the opinion of the Working Group,</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Thank you very =
much, and sorry for writing such a long message,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Jose =
Saldana</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">University of =
Zaragoza</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">______________</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">[1] Ratti, S.; =
Hariri, B.; Shirmohammadi, S., &quot;A Survey of First-Person Shooter =
Gaming Traffic on the Internet,&quot; Internet Computing, IEEE , vol.14, =
no.5, pp.60-69, Sept.-Oct. 2010. URL: <A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D54450=
69&isnumber=3D5562482">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&a=
rnumber=3D5445069&isnumber=3D5562482</A></FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">[2] P. Svoboda, =
W Karner and M. Rupp, &#8220;Traffic Analysis and Modeling for World of =
Warcraft,&#8221; ICC '07. IEEE International Conference on =
Communications, pp.1612-1617, 24-28, Jun. 2007. URL: <A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D42889=
41&isnumber=3D4288671">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&a=
rnumber=3D4288941&isnumber=3D4288671</A></FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">[3] G. Marfia =
and M. Roccetti, &#8220;TCP At Last: Reconsidering TCP&#8217;s Role for =
Wireless Entertainment Centers at Home,&#8221; IEEE Transactions on =
Consumer Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. URL: <A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D56810=
95&isnumber=3D5681060">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&a=
rnumber=3D5681095&isnumber=3D5681060</A></FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">[4] J. Saldana, =
J. Fern=E1ndez-Navajas, J. Ruiz-Mas, J. I. Aznar, E. Viruete and&nbsp; =
L. Casadesus, &#8220;First Person Shooters: Can a Smarter Network Save =
Bandwidth without Annoying the Players?,&#8221; IEEE Communications =
Magazine, Consumer Communications and Networking Series, vol. 49, no. =
11, pp. 190-198, Nov. 2011. URL: <A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D60697=
28&isnumber=3D6069696">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&a=
rnumber=3D6069728&isnumber=3D6069696</A></FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

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Hi,

Attached are draft minutes for the AVTCORE WG session. Sorry for them 
being very late, this is due to me being ill. In the end Roni made most 
of the work to prepare these minutes.

Please review them.

We will see if we can get them added to the proceedings after the WG 
have had some time to look at them.

Cheers

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
Färögatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
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--------------020502010106010704060502
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From internet-drafts@ietf.org  Thu Jan 12 16:39:18 2012
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Subject: [AVTCORE] I-D Action: draft-ietf-avtcore-monarch-09.txt
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A New Internet-Draft is available from the on-line Internet-Drafts director=
ies. This draft is a work item of the Audio/Video Transport Core Maintenanc=
e Working Group of the IETF.

	Title           : Monitoring Architectures for RTP
	Author(s)       : Qin Wu
                          Geoff Hunt
                          Philip Arden
	Filename        : draft-ietf-avtcore-monarch-09.txt
	Pages           : 26
	Date            : 2012-01-12

   This memo proposes an architecture for extending RTCP with a new RTCP
   XR (RFC3611) block type to report new metrics regarding media
   transmission or reception quality, following RTCP guideline
   established in RFC5968.  This memo suggests that a new block should
   contain a single metric or a small number of metrics relevant to a
   single parameter of interest or concern, rather than containing a
   number of metrics which attempt to provide full coverage of all those
   parameters of concern to a specific application.  Applications may
   then "mix and match" to create a set of blocks which covers their set
   of concerns.  Where possible, a specific block should be designed to
   be re-usable across more than one application, for example, for all
   of voice, streaming audio and video.


A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-avtcore-monarch-09.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

This Internet-Draft can be retrieved at:
ftp://ftp.ietf.org/internet-drafts/draft-ietf-avtcore-monarch-09.txt


From bill.wu@huawei.com  Thu Jan 12 16:53:02 2012
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Date: Fri, 13 Jan 2012 08:52:38 +0800
From: Qin Wu <bill.wu@huawei.com>
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Subject: [AVTCORE] Fw: New Version Notification for draft-ietf-avtcore-monarch-09.txt
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Hi,
This version addresses a few comments on the list from Colin, Albrecht and Charles.

Regards!
-Qin

On 13 January 2012, at 8:39 AM, Internet-Drafts@ietf.org wrote:

>A new version of I-D, draft-ietf-avtcore-monarch-09.txt has been successfully submitted by Qin Wu and posted to the IETF repository.

>Title           : Monitoring Architectures for RTP
>Author(s)       : Qin Wu
>                          Geoff Hunt
>                          Philip Arden
>Filename        : draft-ietf-avtcore-monarch-09.txt
>Pages           : 26
>Date            : 2012-01-12

>Abstract:
 >  This memo proposes an architecture for extending RTCP with a new RTCP
>   XR (RFC3611) block type to report new metrics regarding media
>   transmission or reception quality, following RTCP guideline
>   established in RFC5968.  This memo suggests that a new block should
>   contain a single metric or a small number of metrics relevant to a
>   single parameter of interest or concern, rather than containing a
>   number of metrics which attempt to provide full coverage of all those
>   parameters of concern to a specific application.  Applications may
>   then &quot;mix and match&quot; to create a set of blocks which covers their set
>   of concerns.  Where possible, a specific block should be designed to
>   be re-usable across more than one application, for example, for all
>   of voice, streaming audio and video.

                                                                                  

From magnus.westerlund@ericsson.com  Tue Jan 17 01:55:06 2012
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WG,

Unless we still have outstanding issues on Friday, I will submit these
minutes then.

Best regards

Magnus

On 2012-01-12 17:08, Magnus Westerlund wrote:
> Hi,
> 
> Attached are draft minutes for the AVTCORE WG session. Sorry for them 
> being very late, this is due to me being ill. In the end Roni made most 
> of the work to prepare these minutes.
> 
> Please review them.
> 
> We will see if we can get them added to the proceedings after the WG 
> have had some time to look at them.
> 
> Cheers
> 
> Magnus Westerlund
> 
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVM
> ----------------------------------------------------------------------
> Ericsson AB                | Phone  +46 10 7148287
> Färögatan 6                | Mobile +46 73 0949079
> SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
> ----------------------------------------------------------------------


-- 

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
Färögatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
----------------------------------------------------------------------


From magnus.westerlund@ericsson.com  Tue Jan 17 06:00:52 2012
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Subject: Re: [AVTCORE] Proposal for updating TCRTP (RFC 4170)
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Hi,

As you are proposing to go towards a more generic scheme I don't think
this proposal really belongs in the WG, most likely not this area even.

I think this is a topic that primarily are related to Intarea and
Transport. Intarea as the owner of the tunneling work in IETF and
Transport as the actual aggregation and header compression is primarily
transport topics.

A question I would have is where this type of mechanism would make
sense. Where do you have scarce bandwidth capacity and are willing to
pay the downsides of the ingress egress complexities and the impact on
the traffic in regards to additional delay.

Cheers

Magnus


On 2012-01-10 12:34, jsaldana@unizar.es wrote:
> Hello all.
> 
> My name is Jose Saldana, from the University of Zaragoza, in Spain. I am
> new here.
> 
> I would like to share with AVTCORE Work Group a proposal, in case it
> could be considered interesting. The main idea is to update TCRTP. This
> is a "Best current practice" RFC
> (http://datatracker.ietf.org/doc/rfc4170/) which was developed in
> Audio/Video Transport working group in 2005-11. It "describes a method
> to improve the bandwidth utilization of RTP streams over network paths
> that carry multiple Real-time Transport Protocol (RTP) streams in
> parallel between two endpoints, as in voice trunking. The method
> combines standard protocols that provide compression, multiplexing, and
> tunneling over a network path for the purpose of reducing the bandwidth
> used when multiple RTP streams are carried over that path." (from the
> introduction of RFC4170).
> 
> 
> The scheme of TCRTP is:
> 
>   RTP/UDP/IP
> 
>      |
> 
>      |
> 
>    ECRTP (compressing layer). Compresses RTP/UDP/IP headers
> 
>      |
> 
>      |                   
> 
>     PPPMux (multiplexing layer). Includes a number of compressed packets
> into a bigger one
> 
>      |
> 
>      |
> 
>    L2TP     (tunneling layer). Permits its use end-to-end
> 
>      |
> 
>      |
> 
>      IP
> 
> However, there exist many real-time flows that do not use RTP:
> 
> - Online "First Person Shooter" (FPS) games use UDP datagrams, and they
> are one of the most "real-time" applications nowadays. Some examples:
> Counter Strike, Halo, Quake, etc.[1].
> 
> - Online "Massively Multiplayer Online Role Playing Games" (MMORPG):
> They use TCP, but can be considered "real-time", since the actions of
> the players have to be transmitted very quickly to the server. It should
> be taken into account that player vs player fights are one of the
> possible activities of the game. Some examples: World of Warcraft (more
> than 10 million subscribers) [2].
> 
> - TCP is also getting used for media delivery. For many reasons, such as
> avoiding firewalls, the standard IP/ UDP/ RTP protocol stack is
> substituted in many cases by IP/ TCP/ HTTP/ FLV [3].
> 
> - Another interesting scenario is satellite communication links.
> Multiplexing small packets into one packet for transmission would
> improve the efficiency. Satellite links would also find it useful to
> multiplex small TCP packets into one packet – this could be especially
> interesting for compressing TCP ACKs.
> 
> 
> In our recent research activities, we have adapted TCRTP scheme for its
> use when the traffic is not RTP. The idea is to substitute ECRTP by
> other compression scheme which can be used for UDP or TCP headers. In
> 2006, the IETF formed the Robust Header Compression (ROHC) working group
> which created specifications for header compression over links for RTP,
> UDP and TCP.  These specifications were extended to compress headers
> over other networks. For most RTP flows, ROHC is more bandwidth
> efficient than ECRTP, at the cost of implementation complexity. It has a
> special care of context synchronization, defining some states at the
> compressor and decompressor. Once the effort for designing ROHC has been
> conducted, it is worth including it in the compressing and multiplexing
> standard.
> 
> 
> In a recent paper in Nov. issue of IEEE Communications Magazine, it was
> shown that 30% of bandwidth saving can be achieved for 8 FPS different
> games using IPv4. If IPv6 is used, savings can be up to 54% [4]. Another
> recent study, which is still under review, has estimated 45% bandwidth
> saving for World of Warcraft.
> 
> 
> After talking to other researchers, including some of the authors of
> RFC4170, the possible scheme of the proposal could be this one:
> 
> 
> G.711.0 payload compression        TCP     UDP   UDP/RTP
> 
>                  |                    |      |      |
> 
>                  |                     \     |     /
> 
>                  |                       \   |   /
> 
>                  |               nothing or ROHC or ECRTP
> 
>                  |                           |
> 
>                   \                         /
> 
>                     \                     /
> 
>                 multiplexing layer (other or PPPMUX)
> 
>                            |
> 
>                            |
> 
>                tunneling layer (other or GRE or L2TP)
> 
>                            |
> 
>                            |
> 
>                           IP
> 
> It should be more "open" than TCRTP. I mean, it could be "orthogonal" to
> different protocols: different header compression algorithms could be
> used, depending on the application and the scenario; also different
> multiplexing and tunneling protocols could be included. Finally, we have
> also included the G.711.0 "branch": it could be interesting to convert
> G.711 to G.711.0 (a lossless encoding of G.711) and back, using a
> similar tunneling mechanism. In a similar way to TCRTP, the G.711 to
> G.711.0 and vice versa conversion does not involve SIP/SDP/RTSP
> signaling with the endpoints, since G.711 has a fixed RTP payload number.
> 
> We have not written a draft. This is only the first idea, so we look
> forward to hearing the opinion of the Working Group,
> 
> 
> Thank you very much, and sorry for writing such a long message,
> 
> Jose Saldana
> 
> University of Zaragoza
> 
> ______________
> 
> [1] Ratti, S.; Hariri, B.; Shirmohammadi, S., "A Survey of First-Person
> Shooter Gaming Traffic on the Internet," Internet Computing, IEEE ,
> vol.14, no.5, pp.60-69, Sept.-Oct. 2010. URL:
> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5445069&isnumber=5562482
> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5445069&isnumber=5562482>
> 
> [2] P. Svoboda, W Karner and M. Rupp, “Traffic Analysis and Modeling for
> World of Warcraft,” ICC '07. IEEE International Conference on
> Communications, pp.1612-1617, 24-28, Jun. 2007. URL:
> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4288941&isnumber=4288671
> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4288941&isnumber=4288671>
> 
> [3] G. Marfia and M. Roccetti, “TCP At Last: Reconsidering TCP’s Role
> for Wireless Entertainment Centers at Home,” IEEE Transactions on
> Consumer Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. URL:
> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5681095&isnumber=5681060
> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5681095&isnumber=5681060>
> 
> [4] J. Saldana, J. Fernández-Navajas, J. Ruiz-Mas, J. I. Aznar, E.
> Viruete and  L. Casadesus, “First Person Shooters: Can a Smarter Network
> Save Bandwidth without Annoying the Players?,” IEEE Communications
> Magazine, Consumer Communications and Networking Series, vol. 49, no.
> 11, pp. 190-198, Nov. 2011. URL:
> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6069728&isnumber=6069696
> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6069728&isnumber=6069696>
> 


-- 

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
Färögatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
----------------------------------------------------------------------


From jsaldana@unizar.es  Tue Jan 17 10:01:32 2012
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Subject: Re: [AVTCORE] Proposal for updating TCRTP (RFC 4170)
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Magnus,

Thank you very much for your message. I'm going to send the proposal =20
to Internet Area and to Transport Area too. We are merging different =20
ideas and I think one problem of this proposal is in which area and =20
group can it fit.

Regarding the scenarios, we have considered some of them:

- A provider of a real-time service (e.g. game or voip) can have an =20
infrastructure with a number of proxies that can group traffic from =20
different users and send it to the server.

- An Internet caf=E9, where a number (sometimes big) of players share =20
the same access link. Bandwidth is scarce in that scenario.

- A satellite link, where the bandwidth and the pps have to be saved.

Some of the publications I cited in my first message have studied the =20
impact of multiplexing on network parameters, and even in subjective =20
quality. In fact, two days ago I presented in CCNC (Las Vegas) a paper =20
about that:

http://diec.unizar.es/~jsaldana/personal/ccnc_2012_july.pdf

Other related papers are:
http://diec.unizar.es/~jsaldana/personal/gamma_CCNC_2011_in_proc.pdf
http://diec.unizar.es/~jsaldana/personal/ciber_SPECTS_2011_in_proc.pdf


We sent the proposal to avt group because the first version was =20
developed for real-time services, but perhaps the current proposal has =20
become too generic. Nevertheless, the main idea is to use it for =20
real-time services.

Thank you very much,

Jose

> Hi,
>
> As you are proposing to go towards a more generic scheme I don't think
> this proposal really belongs in the WG, most likely not this area even.
>
> I think this is a topic that primarily are related to Intarea and
> Transport. Intarea as the owner of the tunneling work in IETF and
> Transport as the actual aggregation and header compression is primarily
> transport topics.
>
> A question I would have is where this type of mechanism would make
> sense. Where do you have scarce bandwidth capacity and are willing to
> pay the downsides of the ingress egress complexities and the impact on
> the traffic in regards to additional delay.
>
> Cheers
>
> Magnus
>
>
> On 2012-01-10 12:34, jsaldana@unizar.es wrote:
>> Hello all.
>>
>> My name is Jose Saldana, from the University of Zaragoza, in Spain. I am
>> new here.
>>
>> I would like to share with AVTCORE Work Group a proposal, in case it
>> could be considered interesting. The main idea is to update TCRTP. This
>> is a "Best current practice" RFC
>> (http://datatracker.ietf.org/doc/rfc4170/) which was developed in
>> Audio/Video Transport working group in 2005-11. It "describes a method
>> to improve the bandwidth utilization of RTP streams over network paths
>> that carry multiple Real-time Transport Protocol (RTP) streams in
>> parallel between two endpoints, as in voice trunking. The method
>> combines standard protocols that provide compression, multiplexing, and
>> tunneling over a network path for the purpose of reducing the bandwidth
>> used when multiple RTP streams are carried over that path." (from the
>> introduction of RFC4170).
>>
>>
>> The scheme of TCRTP is:
>>
>>   RTP/UDP/IP
>>
>>      |
>>
>>      |
>>
>>    ECRTP (compressing layer). Compresses RTP/UDP/IP headers
>>
>>      |
>>
>>      |
>>
>>     PPPMux (multiplexing layer). Includes a number of compressed packets
>> into a bigger one
>>
>>      |
>>
>>      |
>>
>>    L2TP     (tunneling layer). Permits its use end-to-end
>>
>>      |
>>
>>      |
>>
>>      IP
>>
>> However, there exist many real-time flows that do not use RTP:
>>
>> - Online "First Person Shooter" (FPS) games use UDP datagrams, and they
>> are one of the most "real-time" applications nowadays. Some examples:
>> Counter Strike, Halo, Quake, etc.[1].
>>
>> - Online "Massively Multiplayer Online Role Playing Games" (MMORPG):
>> They use TCP, but can be considered "real-time", since the actions of
>> the players have to be transmitted very quickly to the server. It should
>> be taken into account that player vs player fights are one of the
>> possible activities of the game. Some examples: World of Warcraft (more
>> than 10 million subscribers) [2].
>>
>> - TCP is also getting used for media delivery. For many reasons, such as
>> avoiding firewalls, the standard IP/ UDP/ RTP protocol stack is
>> substituted in many cases by IP/ TCP/ HTTP/ FLV [3].
>>
>> - Another interesting scenario is satellite communication links.
>> Multiplexing small packets into one packet for transmission would
>> improve the efficiency. Satellite links would also find it useful to
>> multiplex small TCP packets into one packet - this could be especially
>> interesting for compressing TCP ACKs.
>>
>>
>> In our recent research activities, we have adapted TCRTP scheme for its
>> use when the traffic is not RTP. The idea is to substitute ECRTP by
>> other compression scheme which can be used for UDP or TCP headers. In
>> 2006, the IETF formed the Robust Header Compression (ROHC) working group
>> which created specifications for header compression over links for RTP,
>> UDP and TCP.  These specifications were extended to compress headers
>> over other networks. For most RTP flows, ROHC is more bandwidth
>> efficient than ECRTP, at the cost of implementation complexity. It has a
>> special care of context synchronization, defining some states at the
>> compressor and decompressor. Once the effort for designing ROHC has been
>> conducted, it is worth including it in the compressing and multiplexing
>> standard.
>>
>>
>> In a recent paper in Nov. issue of IEEE Communications Magazine, it was
>> shown that 30% of bandwidth saving can be achieved for 8 FPS different
>> games using IPv4. If IPv6 is used, savings can be up to 54% [4]. Another
>> recent study, which is still under review, has estimated 45% bandwidth
>> saving for World of Warcraft.
>>
>>
>> After talking to other researchers, including some of the authors of
>> RFC4170, the possible scheme of the proposal could be this one:
>>
>>
>> G.711.0 payload compression        TCP     UDP   UDP/RTP
>>
>>                  |                    |      |      |
>>
>>                  |                     \     |     /
>>
>>                  |                       \   |   /
>>
>>                  |               nothing or ROHC or ECRTP
>>
>>                  |                           |
>>
>>                   \                         /
>>
>>                     \                     /
>>
>>                 multiplexing layer (other or PPPMUX)
>>
>>                            |
>>
>>                            |
>>
>>                tunneling layer (other or GRE or L2TP)
>>
>>                            |
>>
>>                            |
>>
>>                           IP
>>
>> It should be more "open" than TCRTP. I mean, it could be "orthogonal" to
>> different protocols: different header compression algorithms could be
>> used, depending on the application and the scenario; also different
>> multiplexing and tunneling protocols could be included. Finally, we have
>> also included the G.711.0 "branch": it could be interesting to convert
>> G.711 to G.711.0 (a lossless encoding of G.711) and back, using a
>> similar tunneling mechanism. In a similar way to TCRTP, the G.711 to
>> G.711.0 and vice versa conversion does not involve SIP/SDP/RTSP
>> signaling with the endpoints, since G.711 has a fixed RTP payload number.
>>
>> We have not written a draft. This is only the first idea, so we look
>> forward to hearing the opinion of the Working Group,
>>
>>
>> Thank you very much, and sorry for writing such a long message,
>>
>> Jose Saldana
>>
>> University of Zaragoza
>>
>> ______________
>>
>> [1] Ratti, S.; Hariri, B.; Shirmohammadi, S., "A Survey of First-Person
>> Shooter Gaming Traffic on the Internet," Internet Computing, IEEE ,
>> vol.14, no.5, pp.60-69, Sept.-Oct. 2010. URL:
>> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5445069&isnum=
ber=3D5562482
>> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5445069&isnu=
mber=3D5562482>
>>
>> [2] P. Svoboda, W Karner and M. Rupp, "Traffic Analysis and Modeling for
>> World of Warcraft," ICC '07. IEEE International Conference on
>> Communications, pp.1612-1617, 24-28, Jun. 2007. URL:
>> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D4288941&isnum=
ber=3D4288671
>> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D4288941&isnu=
mber=3D4288671>
>>
>> [3] G. Marfia and M. Roccetti, "TCP At Last: Reconsidering TCP's Role
>> for Wireless Entertainment Centers at Home," IEEE Transactions on
>> Consumer Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. URL:
>> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5681095&isnum=
ber=3D5681060
>> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5681095&isnu=
mber=3D5681060>
>>
>> [4] J. Saldana, J. Fern=E1ndez-Navajas, J. Ruiz-Mas, J. I. Aznar, E.
>> Viruete and  L. Casadesus, "First Person Shooters: Can a Smarter Network
>> Save Bandwidth without Annoying the Players?," IEEE Communications
>> Magazine, Consumer Communications and Networking Series, vol. 49, no.
>> 11, pp. 190-198, Nov. 2011. URL:
>> http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D6069728&isnum=
ber=3D6069696
>> <http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D6069728&isnu=
mber=3D6069696>
>>
>
>
> --
>
> Magnus Westerlund
>
> ----------------------------------------------------------------------
> Multimedia Technologies, Ericsson Research EAB/TVM
> ----------------------------------------------------------------------
> Ericsson AB                | Phone  +46 10 7148287
> F=E4r=F6gatan 6                | Mobile +46 73 0949079
> SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
> ----------------------------------------------------------------------
>
>




From magnus.westerlund@ericsson.com  Thu Jan 19 06:44:51 2012
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Subject: [AVTCORE] WG last call for RTCP Extension for Third-party Loss Report (draft-ietf-avtcore-feedback-supression-rtp-09)
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WG,

This is to announce the start of a 2 week WG last call for the
"RTCP Extension for Third-party Loss Report"
with intended status of standards track. The WG last call ends on the
3rf of February.

There is no known IPR disclosure against this draft.

https://datatracker.ietf.org/doc/draft-ietf-avtcore-feedback-supression-rtp/?include_text=1

Cheers

Magnus Westerlund

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Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
Färögatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
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From magnus.westerlund@ericsson.com  Thu Jan 19 06:48:42 2012
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Subject: Re: [AVTCORE] WG last call for RTCP Extension for Third-party Loss Report (draft-ietf-avtcore-feedback-supression-rtp-09)
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Hi,

I have a few comments that I propose have addressed after the WG last
call. I only consider two of those as having any real substance. I
believe the document to ready for publication request when these issues
has been addressed. And when I say addressed, I mean discussed and a way
forward agreed on and that implemented if need. It may very well be to
say that my opinion is rough in regards to the WG's.


1. Section 4.2:

Synchronization source (SSRC):32 bits

      The SSRC value of the media source that is requested to send a
      decoder refresh point or that is indicated that it lost
      synchronization with the video stream.

I think this definition is wrong. Shouldn't it be the SSRC for who's
media stream the media sender is already aware of an expressed need for
taking action that a PLI or FIR reqiests of this SSRC?

I don't think the above is the right text for the spec, but I just
trying to express what the right type of definition would be.

2. Section 5.

"A new feedback value "tplr" needs to be defined for the Third Party
   Loss Report message to be used with Session Description Protocol
   (SDP) [RFC4566] using the Augmented Backus-Naur Form (ABNF)
   [RFC4585]."

I do wonder, do we really need to define a new feedback value? If this
already is associated either with generic NACK, with uses just "nack" or
PLI which is "nack pli" or FIR which is "ccm fir" on the a=rtcp-fb line.
 Wouldn't it be more natural to use "nack tllei" and either "nack pslei"
or "ccm pslei"?


NITS


N1. Section 3:
When a receiver gets a Third Party Loss Report message, it should
   follow the rules for NACK suppression in RFC 4585 and refrain from
   sending a feedback request (e.g., NACK or FIR) for the missing
   packets reported in the message,which is dealt with in the same way
   as receiving NACK.

and

 When the retransmitted packet is
   received by the receiver,it should take its normal behavior as if
   there is no current feedback suppression.

Missing space after comma.

N2. Section 3.

In order not to incur a lot of NACK
   requests due to additional TPLR described above, it is recommended
   that the RTP system sending TPLR should be implemented more closer to
   the media source.

Strange sentence. "more closer" is probably best reduced to just
"closer". However, closer would benefit from a "closer to the media
source than ..."

N3. Section 4.1,

Within the common packet header for feedback messages (as defined in
   section 6.1 of [RFC4585]), the "SSRC of packet sender" field
   indicates the source of the request, and the "SSRC of media source"
   denotes the media sender of the flow for which the indicated losses
   are being suppressed .

additional space at the end of the sentence.

N4. Section 4.1.
  "The BLP's definition is identical to that given in [RFC4585]."

I think a section reference into RFC4585 is recommended.

N5. Section 4.2:

FIR [RFC5104]or PLI [RFC4585].

Missing space between first ref and "or".

And should shouldn't that "or" be an "and"? The message can suppress
both FIR and PLI messages.

N6. When using references, like in section 6.1:
"In SSM RTP sessions as described in [RFC5760], ..."

It would be much clearer if one included the title of the RFC before the
reference, like this:

In SSM RTP sessions as described in "RTP Control Protocol (RTCP)
Extensions for Single-Source Multicast Sessions with Unicast Feedback"
[RFC5760], ...

N7. Section 6.1:
"since the summary feedback does not
   mandate the forwarding of NACK downstream."

Missing initial capital letter on Since.

N8. Section 6.3:
If the translator acting as quality monitor [Monarch]is
   aware of packet loss, it may use the SSRC of monitor as packet sender
   SSRC to create NACK message and send it to the receivers that is not
   aware of packet loss.

it should be the "the monitor" and missing space after [Monarch]

Cheers

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
Färögatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
----------------------------------------------------------------------


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WG,

I just want to remind people about the ongoing second IETF last call. It
ends the 23rd. So please do review the changes.

A side by side diff between the version in the previous IETF last call
and this one.

https://tools.ietf.org/rfcdiff?url1=draft-ietf-avtcore-srtp-vbr-audio-03&difftype=--html&submit=Go!&url2=draft-ietf-avtcore-srtp-vbr-audio-04

Cheers

Magnus

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The IESG has received a request from the Audio/Video Transport Core
Maintenance WG (avtcore) to consider the following document:
- 'Guidelines for the use of Variable Bit Rate Audio with Secure RTP'
  <draft-ietf-avtcore-srtp-vbr-audio-04.txt> as a Proposed Standard

This is a second IETF Last Call to verify the strengthening of recommendati=
ons as a result of
security area review during IESG evaluation, and a change of intended statu=
s from BCP to
Proposed Standard.

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2012-01-23. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


   This memo discusses potential security issues that arise when using
   variable bit rate audio with the secure RTP profile.  Guidelines to
   mitigate these issues are suggested.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-avtcore-srtp-vbr-audio/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-avtcore-srtp-vbr-audio/


No IPR declarations have been submitted directly on this I-D.


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Subject: Re: [AVTCORE] Proposal for updating TCRTP (RFC 4170)
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Magnus,

Although I have also sent the proposal to Internet and Transport areas, =
I have been thinking about your response, and there is some reason for =
considering this proposal in a real-time workgroup: multiplexing is only =
interesting when the size of native packets is small, and this mainly =
happens in real-time services.

Let us make some calculations. We have to take into account the 1500 =
bytes packet size limit. We will define bandwidth relationship as:

BWR =3D Multiplexed_BW / Original_BW =3D Multiplexed_size / =
Original_size (as the time of native and multiplexed packets is the =
same)

1) If we consider a header of 28 bytes (IPv4/UDP) and a payload of 60 =
bytes, then we can multiplex up to =E2=94=941500 / 60=E2=94=98 =E2=89=88 =
23 packets.

The common header at the beginning of a multiplexed packet will be of 25 =
bytes (IPv4 / L2TP / PPPMux).

The compressed header for each packet would be 4 bytes.

Then Multiplexed_size =3D  25 + 23*(4+60) =3D 1497 bytes
And Original_size =3D 23 * (28+60) =3D 2024 bytes

So BWR =3D 0.73 . We are saving 27% of bandwidth. If IPv6 is used, the =
saving grows up to 39%.


2) If header size is 40 bytes (IPv4 /UDP/RTP or IPv4/TCP), we obtain an =
original size of 23 * (40 + 60) =3D 2300 bytes, so BWR =3D 0.65 (35% =
saving). With IPv6 it grows to 45%.


3) But on the other hand, if we consider bigger payloads of e.g. 250 =
bytes, multiplexing is not interesting:

We can multiplex 5 packets, so:

Multiplexed_size =3D 25 + 5*(4+250) =3D1295
Original_size =3D 5*(40+250)=3D1450

So BWR =3D 0.89. We are saving 11% of bandwidth. With IPv6 it is 15%.

_______________

As a conclusion, we see that multiplexing is only interesting for (very) =
small packets. I think the typical applications that use these packets =
are VoIP, FPS games, MMORPG games. I do not know if there are some =
others using tiny packets while not being real-time.

Please consider this argument and tell me your opinion. I have not yet =
received any response from Internet and Transport areas.

Thank you for your attention,

Jose Saldana

-----Mensaje original-----
De: Magnus Westerlund [mailto:magnus.westerlund@ericsson.com]=20
Enviado el: martes, 17 de enero de 2012 15:01
Para: jsaldana@unizar.es
CC: avt@ietf.org
Asunto: Re: [AVTCORE] Proposal for updating TCRTP (RFC 4170)

Hi,

As you are proposing to go towards a more generic scheme I don't think =
this proposal really belongs in the WG, most likely not this area even.

I think this is a topic that primarily are related to Intarea and =
Transport. Intarea as the owner of the tunneling work in IETF and =
Transport as the actual aggregation and header compression is primarily =
transport topics.

A question I would have is where this type of mechanism would make =
sense. Where do you have scarce bandwidth capacity and are willing to =
pay the downsides of the ingress egress complexities and the impact on =
the traffic in regards to additional delay.

Cheers

Magnus


On 2012-01-10 12:34, jsaldana@unizar.es wrote:
> Hello all.
>=20
> My name is Jose Saldana, from the University of Zaragoza, in Spain. I=20
> am new here.
>=20
> I would like to share with AVTCORE Work Group a proposal, in case it=20
> could be considered interesting. The main idea is to update TCRTP.=20
> This is a "Best current practice" RFC
> (http://datatracker.ietf.org/doc/rfc4170/) which was developed in=20
> Audio/Video Transport working group in 2005-11. It "describes a method =

> to improve the bandwidth utilization of RTP streams over network paths =

> that carry multiple Real-time Transport Protocol (RTP) streams in=20
> parallel between two endpoints, as in voice trunking. The method=20
> combines standard protocols that provide compression, multiplexing,=20
> and tunneling over a network path for the purpose of reducing the=20
> bandwidth used when multiple RTP streams are carried over that path."=20
> (from the introduction of RFC4170).
>=20
>=20
> The scheme of TCRTP is:
>=20
>   RTP/UDP/IP
>=20
>      |
>=20
>      |
>=20
>    ECRTP (compressing layer). Compresses RTP/UDP/IP headers
>=20
>      |
>=20
>      |                  =20
>=20
>     PPPMux (multiplexing layer). Includes a number of compressed=20
> packets into a bigger one
>=20
>      |
>=20
>      |
>=20
>    L2TP     (tunneling layer). Permits its use end-to-end
>=20
>      |
>=20
>      |
>=20
>      IP
>=20
> However, there exist many real-time flows that do not use RTP:
>=20
> - Online "First Person Shooter" (FPS) games use UDP datagrams, and=20
> they are one of the most "real-time" applications nowadays. Some =
examples:
> Counter Strike, Halo, Quake, etc.[1].
>=20
> - Online "Massively Multiplayer Online Role Playing Games" (MMORPG):
> They use TCP, but can be considered "real-time", since the actions of=20
> the players have to be transmitted very quickly to the server. It=20
> should be taken into account that player vs player fights are one of=20
> the possible activities of the game. Some examples: World of Warcraft=20
> (more than 10 million subscribers) [2].
>=20
> - TCP is also getting used for media delivery. For many reasons, such=20
> as avoiding firewalls, the standard IP/ UDP/ RTP protocol stack is=20
> substituted in many cases by IP/ TCP/ HTTP/ FLV [3].
>=20
> - Another interesting scenario is satellite communication links.
> Multiplexing small packets into one packet for transmission would=20
> improve the efficiency. Satellite links would also find it useful to=20
> multiplex small TCP packets into one packet =E2=80=93 this could be =
especially=20
> interesting for compressing TCP ACKs.
>=20
>=20
> In our recent research activities, we have adapted TCRTP scheme for=20
> its use when the traffic is not RTP. The idea is to substitute ECRTP=20
> by other compression scheme which can be used for UDP or TCP headers.=20
> In 2006, the IETF formed the Robust Header Compression (ROHC) working=20
> group which created specifications for header compression over links=20
> for RTP, UDP and TCP.  These specifications were extended to compress=20
> headers over other networks. For most RTP flows, ROHC is more=20
> bandwidth efficient than ECRTP, at the cost of implementation=20
> complexity. It has a special care of context synchronization, defining =

> some states at the compressor and decompressor. Once the effort for=20
> designing ROHC has been conducted, it is worth including it in the=20
> compressing and multiplexing standard.
>=20
>=20
> In a recent paper in Nov. issue of IEEE Communications Magazine, it=20
> was shown that 30% of bandwidth saving can be achieved for 8 FPS=20
> different games using IPv4. If IPv6 is used, savings can be up to 54%=20
> [4]. Another recent study, which is still under review, has estimated=20
> 45% bandwidth saving for World of Warcraft.
>=20
>=20
> After talking to other researchers, including some of the authors of=20
> RFC4170, the possible scheme of the proposal could be this one:
>=20
>=20
> G.711.0 payload compression        TCP     UDP   UDP/RTP
>=20
>                  |                    |      |      |
>=20
>                  |                     \     |     /
>=20
>                  |                       \   |   /
>=20
>                  |               nothing or ROHC or ECRTP
>=20
>                  |                           |
>=20
>                   \                         /
>=20
>                     \                     /
>=20
>                 multiplexing layer (other or PPPMUX)
>=20
>                            |
>=20
>                            |
>=20
>                tunneling layer (other or GRE or L2TP)
>=20
>                            |
>=20
>                            |
>=20
>                           IP
>=20
> It should be more "open" than TCRTP. I mean, it could be "orthogonal"=20
> to different protocols: different header compression algorithms could=20
> be used, depending on the application and the scenario; also different =

> multiplexing and tunneling protocols could be included. Finally, we=20
> have also included the G.711.0 "branch": it could be interesting to=20
> convert
> G.711 to G.711.0 (a lossless encoding of G.711) and back, using a=20
> similar tunneling mechanism. In a similar way to TCRTP, the G.711 to
> G.711.0 and vice versa conversion does not involve SIP/SDP/RTSP=20
> signaling with the endpoints, since G.711 has a fixed RTP payload =
number.
>=20
> We have not written a draft. This is only the first idea, so we look=20
> forward to hearing the opinion of the Working Group,
>=20
>=20
> Thank you very much, and sorry for writing such a long message,
>=20
> Jose Saldana
>=20
> University of Zaragoza
>=20
> ______________
>=20
> [1] Ratti, S.; Hariri, B.; Shirmohammadi, S., "A Survey of=20
> First-Person Shooter Gaming Traffic on the Internet," Internet=20
> Computing, IEEE , vol.14, no.5, pp.60-69, Sept.-Oct. 2010. URL:
> =
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5445069&isnum=
b
> er=3D5562482=20
> =
<http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5445069&isnu=
m
> ber=3D5562482>
>=20
> [2] P. Svoboda, W Karner and M. Rupp, =E2=80=9CTraffic Analysis and =
Modeling=20
> for World of Warcraft,=E2=80=9D ICC '07. IEEE International Conference =
on=20
> Communications, pp.1612-1617, 24-28, Jun. 2007. URL:
> =
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D4288941&isnum=
b
> er=3D4288671=20
> =
<http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D4288941&isnu=
m
> ber=3D4288671>
>=20
> [3] G. Marfia and M. Roccetti, =E2=80=9CTCP At Last: Reconsidering =
TCP=E2=80=99s Role=20
> for Wireless Entertainment Centers at Home,=E2=80=9D IEEE Transactions =
on=20
> Consumer Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. URL:
> =
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5681095&isnum=
b
> er=3D5681060=20
> =
<http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D5681095&isnu=
m
> ber=3D5681060>
>=20
> [4] J. Saldana, J. Fern=C3=A1ndez-Navajas, J. Ruiz-Mas, J. I. Aznar, =
E.
> Viruete and  L. Casadesus, =E2=80=9CFirst Person Shooters: Can a =
Smarter=20
> Network Save Bandwidth without Annoying the Players?,=E2=80=9D IEEE=20
> Communications Magazine, Consumer Communications and Networking =
Series, vol. 49, no.
> 11, pp. 190-198, Nov. 2011. URL:
> =
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D6069728&isnum=
b
> er=3D6069696=20
> =
<http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&arnumber=3D6069728&isnu=
m
> ber=3D6069696>
>=20


--=20

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
F=C3=A4r=C3=B6gatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
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<TITLE>RE: [AVTCORE] Proposal for updating TCRTP (RFC 4170)</TITLE>
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<!-- Converted from text/rtf format -->

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">Magnus,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">Although I have</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">also</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">sent the proposal to Internet and =
Transport areas,</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> I have been thinking =
about</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">your response</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">, and =
there is some reason for considering</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT FACE=3D"Calibri">this =
proposal</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> in</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">a</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">real-time workgroup: multiplexing =
is only interesting when the size of native packets is small, and this =
mainly happens in real-time services.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Let us make =
some calculations.</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">We have to take into account =
the</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">1500 bytes</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">packet size</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri"></FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">limit</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">.</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">We will</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">define</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">bandwidth =
relationship</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> as</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">:</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">BWR =3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">Multiplexed_BW =
/</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">Original_BW</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> =3D Multiplexed_size / =
Original_size</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> (as the time of native and =
multiplexed packets is the same)</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">1)</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">If we consider a header of 28 =
bytes (IPv4/UDP) and a payload of</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">6</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">0 bytes, then</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri"> we can =
multiplex up to</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">=E2=94=94</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">1500 =
/</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">6</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">0</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">=E2=94=98</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"></FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">=E2=89=88</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"></FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">2</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">3</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri"> =
packets.</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">The common =
header at the beginning of a multiplexed packet will be of 25 bytes =
(IPv4 / L2TP / PPPMux).</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">The compressed =
header for each packet would be 4 bytes.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">Then</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">Multiplexed_size =
=3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri"></FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us">&nbsp;<FONT FACE=3D"Calibri"></FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT FACE=3D"Calibri">25 =
+</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">2</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">3</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">*(4+</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">6</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">0)</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> =3D</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">14</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">97</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri"> =
bytes</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">And =
Original_size =3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">2</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">3</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> * (</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">28+</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">6</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">0) =
=3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">2024</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> bytes</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">So BWR =3D =
0.7</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">3</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> . We are saving =
2</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">7</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">% of bandwidth</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">. If IPv6 =
is used, the saving grows up to 39%.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">2)</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">If header size is 40 bytes =
(IPv</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">4</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> /UDP/RTP or</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">IPv4/TCP), we obtain an original size of 23 * (40 + 60) =
=3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri"> 2300 bytes, so BWR =3D 0.65 (35% =
saving)</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">. With IPv6 it grows to</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">45%.</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">3)</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">But on the other hand, if we =
consider bigger payloads of e.g.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT FACE=3D"Calibri">250 =
bytes, multiplexing is not interesting:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">We can =
multiplex 5 packets, so:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">Multiplexed_size =3D 25 + 5*(4+250) =
=3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">1295</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Original_size =
=3D 5*(40+250)=3D</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri">1450</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">So BWR =3D =
0.89. We are saving 11% of bandwidth.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri"> With =
IPv6 it is 15%.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">_______________</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">As a =
conclusion, we see that</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">multiplexing</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri"> is only =
interesting for</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">(very)</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT FACE=3D"Calibri">small =
packets</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">. I think the typical applications that use these =
packets are VoIP, FPS games, MMORPG games. I do not know if there are =
some others using tiny packets</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">while</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"><FONT FACE=3D"Calibri"> not being =
real-time.</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Please consider =
this argument and tell me your opinion.</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT FACE=3D"Calibri">I have =
not</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"> <FONT =
FACE=3D"Calibri">yet</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"> <FONT FACE=3D"Calibri">received any response from =
Internet and Transport areas.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Thank you for =
your attention,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"en-us"><FONT FACE=3D"Calibri">Jose =
Saldana</FONT></SPAN><SPAN LANG=3D"es"></SPAN><SPAN =
LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"></SPAN><SPAN LANG=3D"en-us"><FONT =
FACE=3D"Calibri">-----Mensaje original-----<BR>
De: Magnus Westerlund [<A =
HREF=3D"mailto:magnus.westerlund@ericsson.com">mailto:magnus.westerlund@e=
ricsson.com</A>]<BR>
Enviado el: martes, 17 de ener</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">o de 2012 =
15:01<BR>
Para: jsaldana@unizar.es<BR>
CC: avt@ietf.org<BR>
Asunto: Re: [AVTCORE] Proposal for updating TCRTP (RFC =
4170)</FONT></SPAN><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">Hi,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">As you are =
proposing to go towards a more generic scheme I don't think this =
proposal really belongs in the WG, most likely not this area =
even.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">I think this is a =
topic that primarily are related to Intarea and Transport. Intarea as =
the owner of the tunneling work in IETF and Transport as the actual =
aggregation and header compression is primarily transport =
topics.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">A question I would =
have is where this type of mechanism would make sense. Where do you have =
scarce bandwidth capacity and are willing to pay the downsides of the =
ingress egress complexities and the impact on the traffic in regards to =
additional delay.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">Cheers</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">Magnus</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">On 2012-01-10 =
12:34,</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"mailto:jsaldana@unizar.es"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">jsaldana@unizar.es</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"><FONT FACE=3D"Calibri"> =
wrote:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Hello =
all.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; My name is =
Jose Saldana, from the University of Zaragoza, in Spain. I =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; am new =
here.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; I would like =
to share with AVTCORE Work Group a proposal, in case it =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; could be =
considered interesting. The main idea is to update TCRTP. =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; This is a =
&quot;Best current practice&quot; RFC</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
(</FONT></SPAN><SPAN LANG=3D"es"></SPAN><A =
HREF=3D"http://datatracker.ietf.org/doc/rfc4170/"><SPAN =
LANG=3D"es"><FONT =
FACE=3D"Calibri">http://datatracker.ietf.org/doc/rfc4170/</FONT></SPAN><S=
PAN LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">) =
which was developed in </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Audio/Video =
Transport working group in 2005-11. It &quot;describes a method =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; to improve =
the bandwidth utilization of RTP streams over network paths =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; that carry =
multiple Real-time Transport Protocol (RTP) streams in =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; parallel =
between two endpoints, as in voice trunking. The method =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; combines =
standard protocols that provide compression, multiplexing, =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; and tunneling =
over a network path for the purpose of reducing the </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; bandwidth =
used when multiple RTP streams are carried over that path.&quot; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; (from the =
introduction of RFC4170).</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; The scheme of =
TCRTP is:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt;&nbsp;&nbsp; =
RTP/UDP/IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp; ECRTP (compressing layer). =
Compresses RTP/UDP/IP headers</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp; PPPMux (multiplexing =
layer). Includes a number of compressed </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; packets into =
a bigger one</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp; L2TP&nbsp;&nbsp;&nbsp;&nbsp; =
(tunneling layer). Permits its use end-to-end</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; However, =
there exist many real-time flows that do not use RTP:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; - Online =
&quot;First Person Shooter&quot; (FPS) games use UDP datagrams, and =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; they are one =
of the most &quot;real-time&quot; applications nowadays. Some =
examples:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Counter =
Strike, Halo, Quake, etc.[1].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; - Online =
&quot;Massively Multiplayer Online Role Playing Games&quot; =
(MMORPG):</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; They use TCP, =
but can be considered &quot;real-time&quot;, since the actions of =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; the players =
have to be transmitted very quickly to the server. It </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; should be =
taken into account that player vs player fights are one of =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; the possible =
activities of the game. Some examples: World of Warcraft =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; (more than 10 =
million subscribers) [2].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; - TCP is also =
getting used for media delivery. For many reasons, such =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; as avoiding =
firewalls, the standard IP/ UDP/ RTP protocol stack is =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; substituted =
in many cases by IP/ TCP/ HTTP/ FLV [3].</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; - Another =
interesting scenario is satellite communication links.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Multiplexing =
small packets into one packet for transmission would </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; improve the =
efficiency. Satellite links would also find it useful to =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; multiplex =
small TCP packets into one packet =E2=80=93 this could be especially =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; interesting =
for compressing TCP ACKs.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; In our recent =
research activities, we have adapted TCRTP scheme for </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; its use when =
the traffic is not RTP. The idea is to substitute ECRTP =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; by other =
compression scheme which can be used for UDP or TCP headers. =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; In 2006, the =
IETF formed the Robust Header Compression (ROHC) working =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; group which =
created specifications for header compression over links =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; for RTP, UDP =
and TCP.&nbsp; These specifications were extended to compress =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; headers over =
other networks. For most RTP flows, ROHC is more </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; bandwidth =
efficient than ECRTP, at the cost of implementation </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; complexity. =
It has a special care of context synchronization, defining =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; some states =
at the compressor and decompressor. Once the effort for =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; designing =
ROHC has been conducted, it is worth including it in the =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; compressing =
and multiplexing standard.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; In a recent =
paper in Nov. issue of IEEE Communications Magazine, it =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; was shown =
that 30% of bandwidth saving can be achieved for 8 FPS =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; different =
games using IPv4. If IPv6 is used, savings can be up to 54% =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; [4]. Another =
recent study, which is still under review, has estimated =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; 45% bandwidth =
saving for World of Warcraft.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; After talking =
to other researchers, including some of the authors of =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; RFC4170, the =
possible scheme of the proposal could be this one:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; G.711.0 =
payload compression&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
TCP&nbsp;&nbsp;&nbsp;&nbsp; UDP&nbsp;&nbsp; UDP/RTP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp; |&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp; nothing or ROHC or ECRTP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&=
nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
/</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
\&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; multiplexing layer (other =
or PPPMUX)</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tunneling layer (other or GRE or =
L2TP)</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; |</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs=
p;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; IP</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; It should be =
more &quot;open&quot; than TCRTP. I mean, it could be =
&quot;orthogonal&quot; </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; to different =
protocols: different header compression algorithms could =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; be used, =
depending on the application and the scenario; also different =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; multiplexing =
and tunneling protocols could be included. Finally, we =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; have also =
included the G.711.0 &quot;branch&quot;: it could be interesting to =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
convert</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; G.711 to =
G.711.0 (a lossless encoding of G.711) and back, using a =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; similar =
tunneling mechanism. In a similar way to TCRTP, the G.711 =
to</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; G.711.0 and =
vice versa conversion does not involve SIP/SDP/RTSP </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; signaling =
with the endpoints, since G.711 has a fixed RTP payload =
number.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; We have not =
written a draft. This is only the first idea, so we look =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; forward to =
hearing the opinion of the Working Group,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Thank you =
very much, and sorry for writing such a long message,</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Jose =
Saldana</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; University of =
Zaragoza</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
______________</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; [1] Ratti, =
S.; Hariri, B.; Shirmohammadi, S., &quot;A Survey of </FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; First-Person =
Shooter Gaming Traffic on the Internet,&quot; Internet =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Computing, =
IEEE , vol.14, no.5, pp.60-69, Sept.-Oct. 2010. URL:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D5=
445069&amp;isnumb"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arn=
umber=3D5445069&amp;isnumb</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; er=3D5562482 =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
&lt;http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D54450=
69&amp;isnum</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
ber=3D5562482&gt;</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; [2] P. =
Svoboda, W Karner and M. Rupp, =E2=80=9CTraffic Analysis and Modeling =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; for World of =
Warcraft,=E2=80=9D ICC '07. IEEE International Conference on =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
Communications, pp.1612-1617, 24-28, Jun. 2007. URL:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D4=
288941&amp;isnumb"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arn=
umber=3D4288941&amp;isnumb</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; er=3D4288671 =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
&lt;http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D42889=
41&amp;isnum</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
ber=3D4288671&gt;</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; [3] G. Marfia =
and M. Roccetti, =E2=80=9CTCP At Last: Reconsidering TCP=E2=80=99s Role =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; for Wireless =
Entertainment Centers at Home,=E2=80=9D IEEE Transactions on =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Consumer =
Electronics, Vol. 56, N. 4, Nov. 2010, pp. 2233-2240. =
URL:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D5=
681095&amp;isnumb"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arn=
umber=3D5681095&amp;isnumb</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; er=3D5681060 =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
&lt;http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D56810=
95&amp;isnum</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
ber=3D5681060&gt;</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; [4] J. =
Saldana, J. Fern=C3=A1ndez-Navajas, J. Ruiz-Mas, J. I. Aznar, =
E.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Viruete =
and&nbsp; L. Casadesus, =E2=80=9CFirst Person Shooters: Can a Smarter =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; Network Save =
Bandwidth without Annoying the Players?,=E2=80=9D IEEE =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
Communications Magazine, Consumer Communications and Networking Series, =
vol. 49, no.</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; 11, pp. =
190-198, Nov. 2011. URL:</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">&gt;</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D6=
069728&amp;isnumb"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arn=
umber=3D6069728&amp;isnumb</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; er=3D6069696 =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
&lt;http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=3D&amp;arnumber=3D60697=
28&amp;isnum</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
ber=3D6069696&gt;</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">&gt; =
</FONT></SPAN></P>
<BR>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">-- =
</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">Magnus =
Westerlund</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">--------------------------------------------------------=
--------------</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">Multimedia =
Technologies, Ericsson Research EAB/TVM</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">--------------------------------------------------------=
--------------</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">Ericsson =
AB&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp=
;&nbsp;&nbsp;&nbsp; | Phone&nbsp; +46 10 7148287</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">F=C3=A4r=C3=B6gatan =
6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=
&nbsp;&nbsp;&nbsp; | Mobile +46 73 0949079</FONT></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT FACE=3D"Calibri">SE-164 80 =
Stockholm, Sweden| mailto:</FONT></SPAN><SPAN LANG=3D"es"> </SPAN><A =
HREF=3D"mailto:magnus.westerlund@ericsson.com"><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">magnus.westerlund@ericsson.com</FONT></SPAN><SPAN =
LANG=3D"es"></SPAN></A><SPAN LANG=3D"es"></SPAN></P>

<P DIR=3DLTR><SPAN LANG=3D"es"><FONT =
FACE=3D"Calibri">--------------------------------------------------------=
--------------</FONT></SPAN></P>

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From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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Subject: Re: [AVTCORE] Proposal for updating TCRTP (RFC 4170)
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Jose,

Yes, I fully agree with your conclusions that to get substantial benefit
from an mechanism that aggregates and compresses headers you need to
operate on small packets.

The reason I am pushing back on this WG being the right place for
discussion is the fact that you focus on packet streams that aren't RTP.
This WG is chartered for the core extensions and maintenance of RTP.
Based on that we are clearly the right place for RTP related discussion.
However, my understanding of the goal is to generalize the mechanism to
handle flows that uses other protocols that RTP in addition to RTP. Thus
I think the generalized goal is the most important aspect of the work.
When you want input on RTP related aspects then is when this WG really
should be involved.

Sending this WG an occasional pointer to where discussion happens is
fine, but I think you do need to find another place to discuss details
on this.

Cheers

Magnus


On 2012-01-20 10:48, Jose Saldana wrote:
> Magnus,
> 
> Although I havealsosent the proposal to Internet and Transport areas,I
> have been thinking aboutyour response, and there is some reason for
> consideringthis proposalinareal-time workgroup: multiplexing is only
> interesting when the size of native packets is small, and this mainly
> happens in real-time services.
> 
> Let us make some calculations.We have to take into account the1500
> bytespacket sizelimit.We willdefinebandwidth relationshipas:
> 
> BWR =Multiplexed_BW /Original_BW= Multiplexed_size / Original_size(as
> the time of native and multiplexed packets is the same)
> 
> 1)If we consider a header of 28 bytes (IPv4/UDP) and a payload of60
> bytes, thenwe can multiplex up toâ””1500 /60â”˜â‰ˆ23packets.
> 
> The common header at the beginning of a multiplexed packet will be of 25
> bytes (IPv4 / L2TP / PPPMux).
> 
> The compressed header for each packet would be 4 bytes.
> 
> ThenMultiplexed_size = 25 +23*(4+60)=1497bytes
> 
> And Original_size =23* (28+60) =2024bytes
> 
> So BWR = 0.73. We are saving 27% of bandwidth. If IPv6 is used, the
> saving grows up to 39%.
> 
> 2)If header size is 40 bytes (IPv4/UDP/RTP orIPv4/TCP), we obtain an
> original size of 23 * (40 + 60) =2300 bytes, so BWR = 0.65 (35% saving).
> With IPv6 it grows to45%.
> 
> 
> 3)But on the other hand, if we consider bigger payloads of e.g.250
> bytes, multiplexing is not interesting:
> 
> We can multiplex 5 packets, so:
> 
> Multiplexed_size = 25 + 5*(4+250) =1295
> 
> Original_size = 5*(40+250)=1450
> 
> So BWR = 0.89. We are saving 11% of bandwidth.With IPv6 it is 15%.
> 
> _______________
> 
> As a conclusion, we see thatmultiplexingis only interesting
> for(very)small packets. I think the typical applications that use these
> packets are VoIP, FPS games, MMORPG games. I do not know if there are
> some others using tiny packetswhilenot being real-time.
> 
> Please consider this argument and tell me your opinion.I have
> notyetreceived any response from Internet and Transport areas.
> 




-- 

Magnus Westerlund

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Ericsson AB                | Phone  +46 10 7148287
FÃ¤rÃ¶gatan 6                | Mobile +46 73 0949079
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From tom.van_caenegem@alcatel-lucent.com  Fri Jan 20 07:48:16 2012
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Thread-Topic: [AVTCORE] WG last call for RTCP Extension for Third-party Loss Report (draft-ietf-avtcore-feedback-supression-rtp-09)
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Hi Qin, Magnus,

I have reviewed once more the draft, and these are my comments/questions...
Thx
Tom


1)section 1


There are cases where multiple receivers may initiate
   the same, or an equivalent message towards the same media source.

Suggest to have : There are cases where multiple receivers may initiate
   the same, or an equivalent message towards the same media source or same=
 feedback target.

2)section 1

One common cause of such a
   feedback storm is receivers utilizing RTP retransmission [RFC4588] as
   a packet loss recovery technique, sending feedback using RTCP NACK
   messages [RFC4585] without proper dithering of the retransmission
   requests (e.g., not implementing the RFC 4585 dithering rules or
   sending NACKs to a middlebox that doesn't redistribute them to other
   receivers).

Suggest to reposition the ")"  and use "feedback target" iso "middlebox"  (=
aligned with the vocabulary in the abstract)  and add additional clarificat=
ion:

One common cause of such a
   feedback storm is receivers utilizing RTP retransmission [RFC4588] as
   a packet loss recovery technique, sending feedback using RTCP NACK
   messages [RFC4585] without proper dithering of the retransmission
   requests (e.g., not implementing the RFC 4585 dithering rules) or
   sending NACKs to a feedback target that doesn't redistribute them to oth=
er
   receivers and where as a consequence the required feedback suppression b=
ehaviour of RTP receivers conforming to RFC 4588 is not activated.

3)section 1=20

RTCP feedback storms may cause short term overload, and in extreme
   cases to pose a possible risk of increasing network congestion on the
   control channel (e.g.  RTCP feedback), the data channel, or both.  It
   is therefore desirable to provide a way of suppressing unneeded
   feedback.

I think this paragraph has some issues:-can you give an example on where la=
ck of RTCP FB suppression message increases data channel congestion-"it is =
therefore desirable to (..) suppressing unneeded feedbackWhat is meant with=
 "unneeded" feedback?.. from a receiver point of view, the feedback mechani=
sm is desiredas it wants to inform it is missing a packet (and requesting a=
 retransmission). From the retransmission server point of view, this feedba=
ck is also desired as it wants to know who is missing a packet so it can fo=
llow-up with a retransmission.So, instead, just state: "It is therefore des=
irable to provide a way of suppressing feedback". I think it would be bette=
r to highlight that feedback suppression has the obvious effect that the re=
ceiver may not receive -in time- a retransmission, (but further disusison i=
s outside the scope of this document), so it would be good to add:"Such ded=
icated feedback suppression has as consequence that the receiver can be (te=
mporarily) deprived from its repair service"=20

4) I still feel uncomfortbale with the paragraph:

"One approach to this, suggested in [DVB-IPTV], involves sending a
   NACK message to the other clients (or receiver) in the same group as
   the sender of NACK.  However NACK is defined as a receiver report
   sent from a receiver observing a packet loss, therefore it only
   inform others that sender of NACK detected loss while the case where
   the sender of the feedback has received reports that the indicated
   packets were lost is not covered.  This document specifies a new
   third-party loss report for this function.  It supplements the
   existing the use of RTCP NACK packet and further is more precise in
   the uses where the network is active to suppress feedback."

I suggest to delete this as it is more elaborated upon in the retransmissio=
n-for-ssm draft  (which reflects the same topology as addressed by DVB)

5) section 3

The Third Party Loss Report
   (TPLR) message is generated by a RTP system that may not seen the
   actual packet loss.  It is sent following the same timing rule as
   sending NACK defined in [RFC4585].=20

Q: what is RTP system?  Can it be an RTP receiver?

Q: would be good to add a section reference to RFC 4588 wrt the timing rule


6) section 3

"RTP Systems in the network that
   receive a Third Party Loss Report SHOULD NOT send their own
   additional Third Party Loss Report messages for the same packet
   sequence numbers.  They should simply forward the Third Party Loss
   Report message received from upstream direction, additionally, they
   may generate their own Third Party Loss Report that.."

Q: forward to whom?


7) section 3, editorial (I think!);

When a receiver gets a Third Party Loss Report message, it should
   follow the rules for NACK suppression in RFC 4585 and refrain from
   sending a feedback request (e.g., NACK or FIR) for the missing
   packets reported in the message,which is dealt with in the same way
   as receiving NACK.

Suggest to delete ",which is dealt with in the same way
   as receiving NACK.", as being redundant...

8) section 3

"To increase the robustness to the loss of a TPLR or of a transmission
   RTP data packet, TPLR or the RTP packet for the same missing Packet
   may be retransmitted when RTP systems are aware that the same packet
   loss occurs again.  If the additional TPLR arrives at receiver, the
   receiver should deal with the additional TPLR in the same way as
   receiving the first TPLR for the same packet and no additional
   behavior for receiver is required.  When the retransmitted packet is
   received by the receiver,it should take its normal behavior as if
   there is no current feedback suppression."

A couple of items here:

-do you mean "..of a REtransmission RTP data packet"?  Not sure why you lin=
k multiple transmissions of TPLR with multiple transmissions of a retransmi=
ssion packet?

-" when RTP systems are aware that the same packet loss occurs again"=20

Do you mean the loss of the TPLR message?-the sentence is anyhow strange be=
cause when you start the sentence as you did (to increase the robustness..)=
, isn't there a silent assumption that the RTP "system" is NO aware that th=
e packet loss occurs again?=20

-"When the retransmitted packet is
   received by the receiver,it should take its normal behavior as if
   there is no current feedback suppression."

Feedback suppression is based/defined on a per packet basis or group of pac=
kets' basis (as announced in the TPLR).. so if a (retransmission) packet is=
 received by RTP receiver, there is no longer a need to send feedback ( a N=
ACK) by the receiver... So what is the normal behaviour here?


9) section 3:

"Since Third Party Loss Report interacts strongly with repair timing,
   it has to work together with feedback to not adversely impact the
   repair of lost source packets.  In order not to incur a lot of NACK
   requests due to additional TPLR described above, it is recommended
   that the RTP system sending TPLR should be implemented more closer to
   the media source.  When the loss was detected and repair initiated
   much closer to the media source, the delay for the receiver to
   recover from packet loss can be reduced through the combination of
   intermediary feedback to the source and Third Party Loss Report
   downstream."


This paragraph is quite problematic for me.. you cannot really make stateme=
nts on proximity of systems without topology considerations..

-what do you mean with TPL reports must work together with feedback? It sup=
resses feedback!=20

-what does "incur a lot of NACK requests" mean ?

-I do not understand how an RTP system sending TPLR operating in proximity =
to the media source can help here.. as the RTP system sending the TPL needs=
 to wait for a NACK ..from a receiver, before sending a TPLR, this will not=
 really help.



=20

-----Original Message-----
From: avt-bounces@ietf.org [mailto:avt-bounces@ietf.org] On Behalf Of Magnu=
s Westerlund
Sent: donderdag 19 januari 2012 15:45
To: IETF AVTCore WG
Subject: [AVTCORE] WG last call for RTCP Extension for Third-party Loss Rep=
ort (draft-ietf-avtcore-feedback-supression-rtp-09)

WG,

This is to announce the start of a 2 week WG last call for the "RTCP Extens=
ion for Third-party Loss Report"
with intended status of standards track. The WG last call ends on the 3rf o=
f February.

There is no known IPR disclosure against this draft.

https://datatracker.ietf.org/doc/draft-ietf-avtcore-feedback-supression-rtp=
/?include_text=3D1

Cheers

Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
Ericsson AB                | Phone  +46 10 7148287
F=E4r=F6gatan 6                | Mobile +46 73 0949079
SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com
----------------------------------------------------------------------

_______________________________________________
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From ron.even.tlv@gmail.com  Tue Jan 24 01:47:23 2012
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From: "Roni Even" <ron.even.tlv@gmail.com>
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Date: Tue, 24 Jan 2012 11:43:34 +0200
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Subject: [AVTCORE] FW: [dispatch] Media Stream related signaling
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Hi,
I would like to draw your attention to this email that was sent to =
DISPATCH
mailing list.
Please send any comments to dispatch in order to minimize duplication
Thanks
Roni Even
AVTcor co-chair

-----Original Message-----
From: dispatch-bounces@ietf.org [mailto:dispatch-bounces@ietf.org] On =
Behalf
Of Bo Burman
Sent: Monday, January 23, 2012 5:50 PM
To: dispatch@ietf.org
Subject: [dispatch] Media Stream related signaling

Dispatch,

We have requested agenda time for the upcoming meeting to discuss the
subject of Media Stream related signaling. From the feedback we got in
AVTEXT WG on the discussion for a certain problem, the one related to
pausing and resuming sender to middlebox media traffic, it is clear that =
a
more high level discussion needs to happen.

We have two Internet drafts related to the issues we would like to =
discuss.
Media Stream Selection (MESS)
 - draft-westerlund-dispatch-stream-selection-00
RTP Media Stream Pause and Resume
 - draft-westerlund-avtext-rtp-stream-pause-00

The first one (MESS) proposes that for the general selection of media
streams, an end-point within a centralized conferencing scenario desires =
to
receive a media plane oriented rather than RTP/RTCP based signaling, =
which
appears to have benefits as discussed in the draft.

As mentioned, the pause resume draft is targeted for a different use =
case
where a media plane solution has potential for other benefits. This was
discussed and the main outcome of that discussion was three quite =
different
opinions;

a) We already do this signaling using TMMBR (RFC 5104) by setting the
bit-rate value to 0, which the current specs doesn't allow.

b) This should be done in signalling plane, RTP/RTCP shouldn't be =
bloated.
(But I did interpret this as not necessarily needing to be SIP).

c) When it comes to pause/resume, unless it is done using SIP/SDP it =
will
not work through any Session Border Gateway as the session will be torn =
down
after n seconds.

Thus I think it important that we take a discussion around the use =
cases,
existing solutions, limitations in those or the proposal to try to =
determine
what is the most reasonable way of solving the problems and how to =
enable;

1) Receiver based selection of media streams from a larger set of =
streams,
including different quality levels like video resolutions, in a =
centralized
conferencing application.

2) Optimize the transport so that media streams currently not used can =
be
turned off temporarily and then quickly resumed when someone determines =
a
need for the media stream. For example using mechanism (1) but also for
voice activity based, centrally controlled or other mechanisms to select
which media streams are delivered to other session participants.

We are working to revise our Internet drafts. We seek as much input as
possible into this prior to the meeting so that we can ensure that any
discussion are as on topic and focused as possible.

Regards

Bo Burman & Magnus Westerlund

----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
----------------------------------------------------------------------
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From iesg-secretary@ietf.org  Tue Jan 24 13:05:37 2012
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Cc: avtcore chair <avtcore-chairs@tools.ietf.org>, avtcore mailing list <avt@ietf.org>, RFC Editor <rfc-editor@rfc-editor.org>
Subject: [AVTCORE] Protocol Action: 'Guidelines for the use of Variable Bit Rate Audio	with Secure RTP' to Proposed Standard	(draft-ietf-avtcore-srtp-vbr-audio-04.txt)
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The IESG has approved the following document:
- 'Guidelines for the use of Variable Bit Rate Audio with Secure RTP'
  (draft-ietf-avtcore-srtp-vbr-audio-04.txt) as a Proposed Standard

This document is the product of the Audio/Video Transport Core
Maintenance Working Group.

The IESG contact persons are Robert Sparks and Gonzalo Camarillo.

A URL of this Internet Draft is:
http://datatracker.ietf.org/doc/draft-ietf-avtcore-srtp-vbr-audio/




Technical Summary

  This memo discusses potential security issues that arise when using
  variable bit rate audio with the secure RTP profile. When using SRTP
  with voice streams compressed using variable bit rate (VBR) codecs, the
  length of the compressed packets will depend on the characteristics of
  the speech signal. This variation in packet size will leak a small
  amount of information about the contents of the speech signal.
  Guidelines to mitigate these issues are suggested.


Working Group Summary

  There was early on significant debate on how big a security issue this
  problem really was. But it was agreed on the need to document the issue
  and how the issue can be mitigated. Since then there has been good
  consensus on the document.

Document Quality
   This document has gotten reasonable review from people with both
   RTP and Security focus. The quality of the document is good. Additional
   input from the security area during IESG review strengthened some of
   the recommendations which were re-reviewed with a second IETF LC.

Personnel

  Robert Sparks is the responsible AD.
  Magnus Westerlund is the document shepherd.

RFC Editor Note (valid for version -04)

  Please change the Intended Status in the header to Proposed Standard

From bill.wu@huawei.com  Mon Jan 30 01:04:56 2012
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Date: Mon, 30 Jan 2012 17:03:43 +0800
From: Qin Wu <bill.wu@huawei.com>
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To: Magnus Westerlund <magnus.westerlund@ericsson.com>, avt@ietf.org, draft-ietf-avtcore-feedback-supression-rtp@tools.ietf.org
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Subject: Re: [AVTCORE] WG last call for RTCP Extension for Third-party Loss Report (draft-ietf-avtcore-feedback-supression-rtp-09)
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Date: Tue, 31 Jan 2012 10:37:21 +0800
From: Qin Wu <bill.wu@huawei.com>
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To: "Van Caenegem, Tom (Tom)" <tom.van_caenegem@alcatel-lucent.com>, Magnus Westerlund <magnus.westerlund@ericsson.com>, IETF AVTCore WG <avt@ietf.org>
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Subject: Re: [AVTCORE] WG last call for RTCP Extension for Third-partyLoss	Report (draft-ietf-avtcore-feedback-supression-rtp-09)
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Hi, Tom:
----- Original Message ----- 
From: "Van Caenegem, Tom (Tom)" <tom.van_caenegem@alcatel-lucent.com>
To: "Magnus Westerlund" <magnus.westerlund@ericsson.com>; "IETF AVTCore WG" <avt@ietf.org>
Sent: Friday, January 20, 2012 11:48 PM
Subject: Re: [AVTCORE] WG last call for RTCP Extension for Third-partyLoss Report (draft-ietf-avtcore-feedback-supression-rtp-09)


>Hi Qin, Magnus,

>I have reviewed once more the draft, and these are my comments/questions...
>Thx
>Tom

>1)section 1


>There are cases where multiple receivers may initiate
>   the same, or an equivalent message towards the same media source.

>Suggest to have : There are cases where multiple receivers may initiate
>   the same, or an equivalent message towards the same media source or same feedback target.

[Qin]: Okay.

>2)section 1

>One common cause of such a
>   feedback storm is receivers utilizing RTP retransmission [RFC4588] as
>   a packet loss recovery technique, sending feedback using RTCP NACK
>   messages [RFC4585] without proper dithering of the retransmission
>   requests (e.g., not implementing the RFC 4585 dithering rules or
>   sending NACKs to a middlebox that doesn't redistribute them to other
>   receivers).

>Suggest to reposition the ")"  and use "feedback target" iso "middlebox"  (aligned with the vocabulary in the abstract)  and add additional clarification:
>One common cause of such a
>   feedback storm is receivers utilizing RTP retransmission [RFC4588] as
>   a packet loss recovery technique, sending feedback using RTCP NACK
>   messages [RFC4585] without proper dithering of the retransmission
>   requests (e.g., not implementing the RFC 4585 dithering rules) or
>   sending NACKs to a feedback target that doesn't redistribute them to other
>   receivers and where as a consequence the required feedback suppression behaviour of RTP receivers conforming to RFC 4588 is not activated.

[Qin]: Okay.

>3)section 1 

>RTCP feedback storms may cause short term overload, and in extreme
>   cases to pose a possible risk of increasing network congestion on the
>   control channel (e.g.  RTCP feedback), the data channel, or both.  It
>   is therefore desirable to provide a way of suppressing unneeded
>   feedback.

>I think this paragraph has some issues:-can you give an example on where lack of RTCP FB suppression message increases data channel congestion-"it is therefore desirable to (..) suppressing unneeded >feedbackWhat is meant with "unneeded" feedback?.. 

[Qin]: Regarding examples, I like to point you to look at the 1st paragraph and 2nd paragraph of Introduction section and two examples are clearly given over there. 

>from a receiver point of view, the feedback mechanism is desiredas it wants to inform it is missing a packet (and requesting a retransmission). From the >retransmission server point of view, this feedback is >also desired as it wants to know who is missing a packet so it can follow-up with a retransmission.So, instead, just state: "It is therefore desirable to >provide a way of suppressing feedback". I think it >would be better to highlight that feedback suppression has the obvious effect that the receiver may not receive -in time- a retransmission, (but further >disusison is outside the scope of this document), so it >would be good to add:"Such dedicated feedback suppression has as consequence that the receiver can be (temporarily) deprived from its repair service" 


>4) I still feel uncomfortbale with the paragraph:

>"One approach to this, suggested in [DVB-IPTV], involves sending a
>   NACK message to the other clients (or receiver) in the same group as
>   the sender of NACK.  However NACK is defined as a receiver report
>   sent from a receiver observing a packet loss, therefore it only
>   inform others that sender of NACK detected loss while the case where
>   the sender of the feedback has received reports that the indicated
>   packets were lost is not covered. 

>I suggest to delete this as it is more elaborated upon in the retransmission-for-ssm draft  (which reflects the same topology as addressed by DVB)

[Qin]: Okay.

>5) section 3

>The Third Party Loss Report
>   (TPLR) message is generated by a RTP system that may not seen the
>   actual packet loss.  It is sent following the same timing rule as
>   sending NACK defined in [RFC4585]. 

>Q: what is RTP system?  Can it be an RTP receiver?

[Qin]: No, I propose to change RTP system into intermediary for consistency.

>Q: would be good to add a section reference to RFC 4588 wrt the timing rule

[Qin]: Okay.

>6) section 3

>"RTP Systems in the network that
>   receive a Third Party Loss Report SHOULD NOT send their own
>   additional Third Party Loss Report messages for the same packet
>   sequence numbers.  They should simply forward the Third Party Loss
>   Report message received from upstream direction, additionally, they
>   may generate their own Third Party Loss Report that.."

>Q: forward to whom?

[Qin]: to the reciever(s), will add this into the update.

>7) section 3, editorial (I think!);

>When a receiver gets a Third Party Loss Report message, it should
>   follow the rules for NACK suppression in RFC 4585 and refrain from
>   sending a feedback request (e.g., NACK or FIR) for the missing
>   packets reported in the message,which is dealt with in the same way
>   as receiving NACK.

>Suggest to delete ",which is dealt with in the same way
>   as receiving NACK.", as being redundant...

[Qin]: Okay.

>8) section 3

>"To increase the robustness to the loss of a TPLR or of a transmission
>   RTP data packet, TPLR or the RTP packet for the same missing Packet
>   may be retransmitted when RTP systems are aware that the same packet
>   loss occurs again.  If the additional TPLR arrives at receiver, the
>   receiver should deal with the additional TPLR in the same way as
>   receiving the first TPLR for the same packet and no additional
>   behavior for receiver is required.  When the retransmitted packet is
>   received by the receiver,it should take its normal behavior as if
>   there is no current feedback suppression."

>A couple of items here:

>-do you mean "..of a REtransmission RTP data packet"?  Not sure why you link multiple transmissions of TPLR with multiple transmissions of a retransmission packet?

>-" when RTP systems are aware that the same packet loss occurs again" 
>Do you mean the loss of the TPLR message?-the sentence is anyhow strange because when you start the sentence as you did (to increase the robustness..), isn't there a silent assumption that the RTP >"system" is NO aware that the packet loss occurs again? 

[Qin]:You are right, will remove this.

>-"When the retransmitted packet is
>   received by the receiver,it should take its normal behavior as if
>   there is no current feedback suppression."

>Feedback suppression is based/defined on a per packet basis or group of packets' basis (as announced in the TPLR).. so if a (retransmission) packet is received by RTP receiver, there is no longer a need >to send feedback ( a NACK) by the receiver... So what is the normal behaviour here?


[Qin]: You are right, since packet loss recovery mechanism is not focus of this document, I propose to remove the part about multiple transmissions of a retransmission packet from the above paragraph.

>9) section 3:

>"Since Third Party Loss Report interacts strongly with repair timing,
>   it has to work together with feedback to not adversely impact the
>   repair of lost source packets.  In order not to incur a lot of NACK
>   requests due to additional TPLR described above, it is recommended
>   that the RTP system sending TPLR should be implemented more closer to
>   the media source.  When the loss was detected and repair initiated
>   much closer to the media source, the delay for the receiver to
>   recover from packet loss can be reduced through the combination of
>   intermediary feedback to the source and Third Party Loss Report
>   downstream."

>-what do you mean with TPL reports must work together with feedback? It supresses feedback! 

[Qin]: A TPLR is sent to inform some participants in a session about feedback they would not otherwise see, and so the sender of the TPLR has to work together with the sends of NACKs to ensure that appropriate reports are sent to all receivers.

>This paragraph is quite problematic for me.. you cannot really make statements on proximity of systems without topology considerations..

>-what does "incur a lot of NACK requests" mean ?

>-I do not understand how an RTP system sending TPLR operating in proximity to the media source can help here.. as the RTP system sending the TPL needs to wait for a NACK ..from a receiver, before >sending a TPLR, this will not really help.

[Qin]: I agree with you that this draft shouldn't talk about topology. To avoid further confusion, I propose to remove this paragraph.
