[Bloat] [aqm] review: Deployment of RITE mechanisms, in use-case trial testbeds report part 1

Luca De Cicco ldecicco at gmail.com
Thu Mar 3 07:31:27 EST 2016

Dear Ingemar and all,

I hope not to hijack the topic, but I would like to add some bits to the
interesting HAS/DASH
discussion you bootstrapped.
Regarding the performance of HAS/DASH adaptive streaming control algorithm,
the reason for the
poor performance of rate-based algorithms is due to the ON/OFF behaviour of
the clients (i.e. video clients
insert idle periods to control the buffer and concurrent TCP flows can take
advantage of this).
This phenomenon was first uncovered in the IMC 2012 paper that Te-Yuan et
al. named "the downward
spiral effect" and is also experimentally shown in the following paper in
the case of several "rate based" algorithms
(sorry for the advertisement ;)) where we proposed a buffer-based adaptive
streaming control algorithm:

L. De Cicco, V. Caldaralo, V. Palmisano, and S. Mascolo
ELASTIC: a Client-side Controller for Dynamic Adaptive Streaming over HTTP
Proc. of Packet Video Workshop 2013, San Jose, CA, USA, December 2013

A more theoretical explanation of rate-based and buffer-based approaches
can be found here
 where some properties of hysteresis buffer-based controllers are shown:

Giuseppe Cofano, Luca De Cicco, Saverio Mascolo
Characterizing Adaptive Video Streaming Control Systems
Proc. of American Control Conference (ACC 2015), Chicago, USA, July 1-3 2015

Luca De Cicco
Assistant Professor
Politecnico di Bari

On Thu, Mar 3, 2016 at 1:13 PM Ingemar Johansson S <
ingemar.s.johansson at ericsson.com> wrote:

> Hi
> Thanks for the pointer to the RITE paper, will read it carefully.
> Some comments on HAS or DASH
> The HAS behavior when subject to different AQMs and other competing
> background traffic, depends heavily the rate control algorithm.
> Investigations we have done and also e.g. the Netflix papers and lately
> also the BOLA paper (link below) shows that rate based algorithms are more
> easily starved out by competing traffic than the buffer level based
> algorithms. The bufferbased algorithms (Netflix, BOLA) are more
> opportunistic and TCP is more allowed to work like large file downloads
> when the links are fully utilized. Rate based algorithms on the other hand
> can more easily end up in a vicious circle, a low download rate is
> detected, so the next segment requested is with a reduced rate, other
> traffic will grab a larger share, and this repeats itself until the lowest
> rate is reached.
> This is elaborated upon in the paper "A Buffer-Based Approach to Rate
> Adaptation: Evidence from a Large Video Streaming Service" by Te-Yuan Huang
> et.al.
> I don't have full insight how MS Silverlight operates so I cannot quantify
> it is rate based or buffer based.
> BOLA : http://arxiv.org/pdf/1601.06748.pdf
> /Ingemar
> > -----Original Message-----
> > From: Fred Baker (fred) [mailto:fred at cisco.com]
> > Sent: den 2 mars 2016 19:09
> > To: Dave Täht
> > Cc: aqm at ietf.org; bloat at lists.bufferbloat.net
> > Subject: Re: [aqm] [Bloat] review: Deployment of RITE mechanisms, in use-
> > case trial testbeds report part 1
> >
> >
> > > On Feb 27, 2016, at 11:04 AM, Dave Täht <dave at taht.net> wrote:
> > >
> > > https://reproducingnetworkresearch.wordpress.com/2014/06/03/cs244-
> > 14-confused-timid-and-unstable-picking-a-video-streaming-rate-is-hard/
> > >
> > >>   o the results are very poor with a particular popular AQM
> > >
> > > Define "very poor". ?
> >
> > Presuming this is Adaptive Bitrate Video, as in Video-in-TCP, we (as in
> Cisco
> > engineers, not me personally; you have met them) have observed this as
> > well. Our belief is that this is at least in part a self-inflicted
> wound; when the
> > codec starts transmission on any four second segment except the first,
> there
> > is no slow-start phase because the TCP session is still open (and in the
> case of
> > some services, there are several TCP sessions open and the application
> > chooses the one with the highest cwnd value). You can now think of the
> > behavior of the line as repeating a four phase sequence: nobody is
> talking,
> > then one is talking, then both are, and then the other is talking. When
> only
> > one is talking, whichever it is, its cwnd value is slowing increasing -
> especially
> > if cwnd*mss/rtt < bottleneck line rate, minimizing RTT. At the start of
> the
> > "both are talking" phase, the one already talking has generally found a
> cwnd
> > value that fills the line and its RTT is slowly increasing. The one
> starting sends
> > a burst of cwnd packets, creating an instant queue and often causing one
> or
> > both to drop a packet - reducing their respective cwnd values. Depending
> on
> > the TCP implementation in question at the sender, if the induced drop
> isn't a
> > single packet but is two or three, that can make the affected session
> pause
> > for as many RTO timeouts (Reno), RTTs (New Reno), or at least retransmit
> > the lost packets in the subsequent RTT and then reduce cwnd by at least
> that
> > amount (cubic) and maybe half (SACK).
> _______________________________________________
> aqm mailing list
> aqm at ietf.org
> https://www.ietf.org/mailman/listinfo/aqm
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