Re: [Cerowrt-devel] [Make-wifi-fast] [Starlink] Due Aug 2: Internet Quality workshop CFP for the internet architecture board

[Luca Muscariello <muscariello@ieee.org>]

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For those who might be interested in Little's law
there is a nice paper by John Little on the occasion
of the 50th anniversary  of the result.

https://www.informs.org/Blogs/Operations-Research-Forum/Little-s-Law-as-Viewed-on-its-50th-Anniversary

https://www.informs.org/content/download/255808/2414681/file/little_paper.pdf

Nice read.
Luca

P.S.
Who has not a copy of L. Kleinrock's books? I do have and am not ready to
lend them!

On Fri, Jul 9, 2021 at 11:01 AM Leonard Kleinrock <lk@cs.ucla.edu> wrote:

> David,
>
> I totally appreciate  your attention to when and when not analytical
> modeling works. Let me clarify a few things from your note.
>
> First, Little's law (also known as Little’s lemma or, as I use in my book,
> Little’s result) does not assume Poisson arrivals -  it is good for *any*
> arrival process and any service process and is an equality between time
> averages.  It states that the time average of the number in a system (for a
> sample path *w)* is equal to the average arrival rate to the system
> multiplied by the time-averaged time in the system for that sample path.
> This is often written as   NTimeAvg =λ·TTimeAvg .  Moreover, if the
> system is also ergodic, then the time average equals the ensemble average
> and we often write it as N ̄ = λ T ̄ .  In any case, this requires
> neither Poisson arrivals nor exponential service times.
>
> Queueing theorists often do study the case of Poisson arrivals.  True, it
> makes the analysis easier, yet there is a better reason it is often used,
> and that is because the sum of a large number of independent stationary
> renewal processes approaches a Poisson process.  So nature often gives us
> Poisson arrivals.
>
> Best,
> Len
>
>
>
> On Jul 8, 2021, at 12:38 PM, David P. Reed <dpreed@deepplum.com> wrote:
>
> I will tell you flat out that the arrival time distribution assumption
> made by Little's Lemma that allows "estimation of queue depth" is totally
> unreasonable on ANY Internet in practice.
>
>
> The assumption is a Poisson Arrival Process. In reality, traffic arrivals
> in real internet applications are extremely far from Poisson, and, of
> course, using TCP windowing, become highly intercorrelated with crossing
> traffic that shares the same queue.
>
>
> So, as I've tried to tell many, many net-heads (people who ignore
> applications layer behavior, like the people that think latency doesn't
> matter to end users, only throughput), end-to-end packet arrival times on a
> practical network are incredibly far from Poisson - and they are more like
> fractal probability distributions, very irregular at all scales of time.
>
>
> So, the idea that iperf can estimate queue depth by Little's Lemma by just
> measuring saturation of capacity of a path is bogus.The less Poisson, the
> worse the estimate gets, by a huge factor.
>
>
>
>
> Where does the Poisson assumption come from?  Well, like many theorems, it
> is the simplest tractable closed form solution - it creates a simplified
> view, by being a "single-parameter" distribution (the parameter is called
> lambda for a Poisson distribution).  And the analysis of a simple queue
> with poisson arrival distribution and a static, fixed service time is the
> first interesting Queueing Theory example in most textbooks. It is
> suggestive of an interesting phenomenon, but it does NOT characterize any
> real system.
>
>
> It's the queueing theory equivalent of "First, we assume a spherical
> cow...". in doing an example in a freshman physics class.
>
>
> Unfortunately, most networking engineers understand neither queuing theory
> nor application networking usage in interactive applications. Which makes
> them arrogant. They assume all distributions are poisson!
>
>
>
>
> On Tuesday, July 6, 2021 9:46am, "Ben Greear" <greearb@candelatech.com>
> said:
>
> > Hello,
> >
> > I am interested to hear wish lists for network testing features. We make
> test
> > equipment, supporting lots
> > of wifi stations and a distributed architecture, with built-in udp, tcp,
> ipv6,
> > http, ... protocols,
> > and open to creating/improving some of our automated tests.
> >
> > I know Dave has some test scripts already, so I'm not necessarily
> looking to
> > reimplement that,
> > but more fishing for other/new ideas.
> >
> > Thanks,
> > Ben
> >
> > On 7/2/21 4:28 PM, Bob McMahon wrote:
> > > I think we need the language of math here. It seems like the network
> > power metric, introduced by Kleinrock and Jaffe in the late 70s, is
> something
> > useful.
> > > Effective end/end queue depths per Little's law also seems useful.
> Both are
> > available in iperf 2 from a test perspective. Repurposing test
> techniques to
> > actual
> > > traffic could be useful. Hence the question around what exact telemetry
> > is useful to apps making socket write() and read() calls.
> > >
> > > Bob
> > >
> > > On Fri, Jul 2, 2021 at 10:07 AM Dave Taht <dave.taht@gmail.com
> > <mailto:dave.taht@gmail.com <dave.taht@gmail.com>>> wrote:
> > >
> > > In terms of trying to find "Quality" I have tried to encourage folk to
> > > both read "zen and the art of motorcycle maintenance"[0], and Deming's
> > > work on "total quality management".
> > >
> > > My own slice at this network, computer and lifestyle "issue" is aiming
> > > for "imperceptible latency" in all things. [1]. There's a lot of
> > > fallout from that in terms of not just addressing queuing delay, but
> > > caching, prefetching, and learning more about what a user really needs
> > > (as opposed to wants) to know via intelligent agents.
> > >
> > > [0] If you want to get depressed, read Pirsig's successor to "zen...",
> > > lila, which is in part about what happens when an engineer hits an
> > > insoluble problem.
> > > [1] https://www.internetsociety.org/events/latency2013/
> > <https://www.internetsociety.org/events/latency2013/>
> > >
> > >
> > >
> > > On Thu, Jul 1, 2021 at 6:16 PM David P. Reed <dpreed@deepplum.com
> > <mailto:dpreed@deepplum.com <dpreed@deepplum.com>>> wrote:
> > > >
> > > > Well, nice that the folks doing the conference  are willing to
> > consider that quality of user experience has little to do with
> signalling rate at
> > the
> > > physical layer or throughput of FTP transfers.
> > > >
> > > >
> > > >
> > > > But honestly, the fact that they call the problem "network quality"
> > suggests that they REALLY, REALLY don't understand the Internet isn't
> the hardware
> > or
> > > the routers or even the routing algorithms *to its users*.
> > > >
> > > >
> > > >
> > > > By ignoring the diversity of applications now and in the future,
> > and the fact that we DON'T KNOW what will be coming up, this conference
> will
> > likely fall
> > > into the usual trap that net-heads fall into - optimizing for some
> > imaginary reality that doesn't exist, and in fact will probably never be
> what
> > users
> > > actually will do given the chance.
> > > >
> > > >
> > > >
> > > > I saw this issue in 1976 in the group developing the original
> > Internet protocols - a desire to put *into the network* special tricks
> to optimize
> > ASR33
> > > logins to remote computers from terminal concentrators (aka remote
> > login), bulk file transfers between file systems on different
> time-sharing
> > systems, and
> > > "sessions" (virtual circuits) that required logins. And then trying to
> > exploit underlying "multicast" by building it into the IP layer, because
> someone
> > > thought that TV broadcast would be the dominant application.
> > > >
> > > >
> > > >
> > > > Frankly, to think of "quality" as something that can be "provided"
> > by "the network" misses the entire point of "end-to-end argument in
> system
> > design".
> > > Quality is not a property defined or created by The Network. If you
> want
> > to talk about Quality, you need to talk about users - all the users at
> all times,
> > > now and into the future, and that's something you can't do if you don't
> > bother to include current and future users talking about what they might
> expect
> > to
> > > experience that they don't experience.
> > > >
> > > >
> > > >
> > > > There was much fighting back in 1976 that basically involved
> > "network experts" saying that the network was the place to "solve" such
> issues as
> > quality,
> > > so applications could avoid having to solve such issues.
> > > >
> > > >
> > > >
> > > > What some of us managed to do was to argue that you can't "solve"
> > such issues. All you can do is provide a framework that enables
> different uses to
> > > *cooperate* in some way.
> > > >
> > > >
> > > >
> > > > Which is why the Internet drops packets rather than queueing them,
> > and why diffserv cannot work.
> > > >
> > > > (I know the latter is conftroversial, but at the moment, ALL of
> > diffserv attempts to talk about end-to-end applicaiton specific metrics,
> but
> > never, ever
> > > explains what the diffserv control points actually do w.r.t. what the
> IP
> > layer can actually control. So it is meaningless - another violation of
> the
> > > so-called end-to-end principle).
> > > >
> > > >
> > > >
> > > > Networks are about getting packets from here to there, multiplexing
> > the underlying resources. That's it. Quality is a whole different thing.
> Quality
> > can
> > > be improved by end-to-end approaches, if the underlying network
> provides
> > some kind of thing that actually creates a way for end-to-end
> applications to
> > > affect queueing and routing decisions, and more importantly getting
> > "telemetry" from the network regarding what is actually going on with
> the other
> > > end-to-end users sharing the infrastructure.
> > > >
> > > >
> > > >
> > > > This conference won't talk about it this way. So don't waste your
> > time.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > On Wednesday, June 30, 2021 8:12pm, "Dave Taht"
> > <dave.taht@gmail.com <mailto:dave.taht@gmail.com <dave.taht@gmail.com>>>
> said:
> > > >
> > > > > The program committee members are *amazing*. Perhaps, finally,
> > we can
> > > > > move the bar for the internet's quality metrics past endless,
> > blind
> > > > > repetitions of speedtest.
> > > > >
> > > > > For complete details, please see:
> > > > > https://www.iab.org/activities/workshops/network-quality/
> > <https://www.iab.org/activities/workshops/network-quality/>
> > > > >
> > > > > Submissions Due: Monday 2nd August 2021, midnight AOE
> > (Anywhere On Earth)
> > > > > Invitations Issued by: Monday 16th August 2021
> > > > >
> > > > > Workshop Date: This will be a virtual workshop, spread over
> > three days:
> > > > >
> > > > > 1400-1800 UTC Tue 14th September 2021
> > > > > 1400-1800 UTC Wed 15th September 2021
> > > > > 1400-1800 UTC Thu 16th September 2021
> > > > >
> > > > > Workshop co-chairs: Wes Hardaker, Evgeny Khorov, Omer Shapira
> > > > >
> > > > > The Program Committee members:
> > > > >
> > > > > Jari Arkko, Olivier Bonaventure, Vint Cerf, Stuart Cheshire,
> > Sam
> > > > > Crowford, Nick Feamster, Jim Gettys, Toke Hoiland-Jorgensen,
> > Geoff
> > > > > Huston, Cullen Jennings, Katarzyna Kosek-Szott, Mirja
> > Kuehlewind,
> > > > > Jason Livingood, Matt Mathias, Randall Meyer, Kathleen
> > Nichols,
> > > > > Christoph Paasch, Tommy Pauly, Greg White, Keith Winstein.
> > > > >
> > > > > Send Submissions to: network-quality-workshop-pc@iab.org
> > <mailto:network-quality-workshop-pc@iab.org
> <network-quality-workshop-pc@iab.org>>.
> > > > >
> > > > > Position papers from academia, industry, the open source
> > community and
> > > > > others that focus on measurements, experiences, observations
> > and
> > > > > advice for the future are welcome. Papers that reflect
> > experience
> > > > > based on deployed services are especially welcome. The
> > organizers
> > > > > understand that specific actions taken by operators are
> > unlikely to be
> > > > > discussed in detail, so papers discussing general categories
> > of
> > > > > actions and issues without naming specific technologies,
> > products, or
> > > > > other players in the ecosystem are expected. Papers should not
> > focus
> > > > > on specific protocol solutions.
> > > > >
> > > > > The workshop will be by invitation only. Those wishing to
> > attend
> > > > > should submit a position paper to the address above; it may
> > take the
> > > > > form of an Internet-Draft.
> > > > >
> > > > > All inputs submitted and considered relevant will be published
> > on the
> > > > > workshop website. The organisers will decide whom to invite
> > based on
> > > > > the submissions received. Sessions will be organized according
> > to
> > > > > content, and not every accepted submission or invited attendee
> > will
> > > > > have an opportunity to present as the intent is to foster
> > discussion
> > > > > and not simply to have a sequence of presentations.
> > > > >
> > > > > Position papers from those not planning to attend the virtual
> > sessions
> > > > > themselves are also encouraged. A workshop report will be
> > published
> > > > > afterwards.
> > > > >
> > > > > Overview:
> > > > >
> > > > > "We believe that one of the major factors behind this lack of
> > progress
> > > > > is the popular perception that throughput is the often sole
> > measure of
> > > > > the quality of Internet connectivity. With such narrow focus,
> > people
> > > > > don’t consider questions such as:
> > > > >
> > > > > What is the latency under typical working conditions?
> > > > > How reliable is the connectivity across longer time periods?
> > > > > Does the network allow the use of a broad range of protocols?
> > > > > What services can be run by clients of the network?
> > > > > What kind of IPv4, NAT or IPv6 connectivity is offered, and
> > are there firewalls?
> > > > > What security mechanisms are available for local services,
> > such as DNS?
> > > > > To what degree are the privacy, confidentiality, integrity
> > and
> > > > > authenticity of user communications guarded?
> > > > >
> > > > > Improving these aspects of network quality will likely depend
> > on
> > > > > measurement and exposing metrics to all involved parties,
> > including to
> > > > > end users in a meaningful way. Such measurements and exposure
> > of the
> > > > > right metrics will allow service providers and network
> > operators to
> > > > > focus on the aspects that impacts the users’ experience
> > most and at
> > > > > the same time empowers users to choose the Internet service
> > that will
> > > > > give them the best experience."
> > > > >
> > > > >
> > > > > --
> > > > > Latest Podcast:
> > > > >
> >
> https://www.linkedin.com/feed/update/urn:li:activity:6791014284936785920/
> > <
> https://www.linkedin.com/feed/update/urn:li:activity:6791014284936785920/>
> > > > >
> > > > > Dave Täht CTO, TekLibre, LLC
> > > > > _______________________________________________
> > > > > Cerowrt-devel mailing list
> > > > > Cerowrt-devel@lists.bufferbloat.net
> > <mailto:Cerowrt-devel@lists.bufferbloat.net
> <Cerowrt-devel@lists.bufferbloat.net>>
> > > > > https://lists.bufferbloat.net/listinfo/cerowrt-devel
> > <https://lists.bufferbloat.net/listinfo/cerowrt-devel>
> > > > >
> > >
> > >
> > >
> > > --
> > > Latest Podcast:
> > >
> https://www.linkedin.com/feed/update/urn:li:activity:6791014284936785920/
> > <
> https://www.linkedin.com/feed/update/urn:li:activity:6791014284936785920/>
> > >
> > > Dave Täht CTO, TekLibre, LLC
> > > _______________________________________________
> > > Make-wifi-fast mailing list
> > > Make-wifi-fast@lists.bufferbloat.net
> > <mailto:Make-wifi-fast@lists.bufferbloat.net
> <Make-wifi-fast@lists.bufferbloat.net>>
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> > >
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> >
> >
> > --
> > Ben Greear <greearb@candelatech.com>
> > Candela Technologies Inc http://www.candelatech.com
> >
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