FW: [AVT] RTCP unicast feedback for measurement applications?

[Ivan R. Judson]

Network Monitoring reading.

> -----Original Message-----
> From: avt-admin at ietf.org [mailto:avt-admin at ietf.org] On 
> Behalf Of Eve Schooler
> Sent: Thursday, March 13, 2003 1:38 PM
> To: Fiandra Riccardo; Joerg Ott; Julian Chesterfield
> Cc: avt at ietf.org
> Subject: Re: [AVT] RTCP unicast feedback for measurement applications?
> 
> 
> Fiandra,
> 
> Finally, here are pointers to the paper that extends the 
> ideas proposed in the I-D, and that I promised below.
>   
> The paper analyzes the bandwidth savings of summarisation,
> and presents a couple additional techniques (biasing and 
> hierarchical summarisation) that 
> - combine well with unicast feedback and generic summarisation, 
> - provide further rtcp scalability, and 
> - offer additional application contexts for rtcp.
> 
> 
> http://www.research.att.com/~schooler/papers/rtcp-summary-pape
r.techreport.ps
> 
> http://www.research.att.com/~schooler/papers/rtcp-summary-pape
r.techreport.pdf
>   
> A shorter version will appear in the 2nd IEEE International 
> Symposium on Network Computing and Applications, NCA-03, 
> April 16-18, 2003, Cambridge, MA.
>  
>  http://www.research.att.com/~schooler/papers/rtcp-summary-paper.ps
>  http://www.research.att.com/~schooler/papers/rtcp-summary-paper.pdf
> 
> E.
> 
> > -----Original Message-----
> > From: Eve Schooler [mailto:schooler at research.att.com]
> > Sent: martedì 4 febbraio 2003 2.02
> > To: Fiandra Riccardo
> > Cc: Eve Schooler; Julian Chesterfield; Joerg Ott; avt at ietf.org
> > Subject: Re: [AVT] RTCP unicast feedback for measurement 
> applications?
> > 
> > 
> > Fiandra Riccardo <riccardo.fiandra at fastweb.it> wrote:
> > 
> > >I was interested in the "RTCP Extensions for Single-Source 
> Multicast 
> > >Sessions with Unicast Feedback" draft. Actually, I was 
> wondering if 
> > >it is also targeted to have a very large and distribuited network 
> > >measurement framework. Where multicast receivers 
> (thousands) use RTCP 
> > >to send report to a measurement collector about packet 
> loss, jitter, 
> > >or other. I see really many advantages on that for e2e 
> measurements, 
> > >especially in a scenario where thousands of receivers are always 
> > >connected to the network and cannot send multicast (common 
> scenario 
> > >for an operator, even without SSM...).
> > >
> > >My questions are:
> > >-Was this a scenario of application when writing the draft?
> > 
> > Absolutely, though the primary focus of the draft was to solve the 
> > problem posed by the removal/restriction of the backchannel 
> caused by 
> > SSM and other uni-directional or asymmetric topologies. Solving the 
> > feedback problem for SSM gives us the blueprint for other 
> > unicast-based feedback architectures, including ones for network 
> > measurement in general.
> > 
> > >-In this case, could I use the RTCP channel multicasted to the 
> > >receivers to control them?
> > 
> > Yes you could.  This is certainly what we envision in the RTCP 
> > context; use the multicast channel in the source-to-receiver 
> > direction, and use the unicast backchannels in the 
> receiver-to-source 
> > direction.
> > 
> > We also propose to use the multicast channel either:
> > - to reflect receiver feedback (received on the unicast 
> backchannels)
> >   back out on the multicast channel to reach all receivers, or
> > - to redistribute to the receivers feedback summaries
> >   (receiver feedback collected at the source and aggregated into
> >   a single mathematical distribution) back out on the multicast 
> > channel.
> > 
> > >-Do you see any extension possible also for ptp rtp connections 
> > >(forward rtcp reports to another device?)
> > 
> > In section 10 of draft-ietf-avt-rtcpssm-02.txt, we use
> > an extension to SDP to indicate the device to which the 
> feedback gets 
> > reported.  This is done following the proposal for SDP 
> source filters 
> > documented in draft-ietf-mmusic-sdp-srcfilter-00.txt.
> > 
> > We also just completed a paper that expands upon the ideas
> > in the I-D and that should provide further application scenarios.  
> > I'll post it here shortly.
> > 
> > Eve
> > 
> > -=-=-=-=-
> > 
> > Eve M. Schooler                 Voice:  1-650-330-7913
> > AT&T Labs - Research            FAX:    1-650-463-7037
> > 75 Willow Road                  E-mail: schooler at research.att.com
> > Menlo Park, CA, USA 94025       
> http://www.research.att.com/~schooler
> 
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