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[89.243.172.136]) by smtp.googlemail.com with ESMTPSA id jn7sm32120544wjb.5.2016.09.21.00.32.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Sep 2016 00:32:18 -0700 (PDT) To: dpreed@reed.com References: <1474146692.035424358@mobile.rackspace.com> <1474403262.975213436@apps.rackspace.com> Cc: Dave Taht , Jonathan Morton , "cerowrt-devel@lists.bufferbloat.net" From: Alan Jenkins Message-ID: <4a1fd48e-b1c4-2e75-d55a-417a83a572d4@gmail.com> Date: Wed, 21 Sep 2016 08:32:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <1474403262.975213436@apps.rackspace.com> Content-Type: multipart/alternative; boundary="------------4DEE2DE5B7470D7203D04553" Subject: Re: [Cerowrt-devel] BBR congestion control algorithm for TCP innet-next X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Sep 2016 07:32:21 -0000 This is a multi-part message in MIME format. --------------4DEE2DE5B7470D7203D04553 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit On 20/09/16 21:27, dpreed@reed.com wrote: > I constantly see the claim that >50% of transmitted data on the Internet are streaming TV. However, the source seems to be as hard to nail down I don't think the source is hard to identify. It's Sandvine press releases. That's what the periodic stories on Ars Technica are always derived from. https://www.sandvine.com/pr/2015/12/7/sandvine-over-70-of-north-american-traffic-is-now-streaming-video-and-audio.html > as the original claim that >50% of Internet traffic was pirated music being sent over bittorrent. > > You recently repeated that statistic as if it were a verified fact. > > I remember that in the early days of WiFi DSSS availability the claim was repeatedly made from podiums at conferences I attended that "the amount of WiFi in parking lots on Sand Hill Road [then the location of most major Silicon Valley VC firms] had made it so that people could not open their car doors with their remote keys". This was not intended as hyperbole or a joke - I got into the habit of asking the speakers how they knew this, and they told me that their VC friends had all had it happen to them... > > Propaganda consists of clever stories that "sound plausible" and which are spread by people because they seem to support something they *wish* were true for some reason. > > I suspect that this 70% number is more propaganda of this sort. > > In case it is not obvious, the beneficiaries of this particular propaganda are those who want to claim various things - that the Internet is now just TV broadcasting and thus should be treated that way (Internet Access Providers should select "channels", charge for allowing them through to customers, improving the "quality of programming" and censoring anything offensive, as just one example) > > So I am extremely curious as to an actual source of such a number, how it was measured, and how its validity can be tested reproducibly. > > Some may remember that the original discovery of "bufferbloat" was due to the fact that Comcast deployed Sandvine gear in its network to send RST packets for any connections that involved multiple concurrent TCP uploads (using DPI technology to guess what TCP connections to RST and the right header data to put on the RST packets). > > Their argument for why they *had* to do that was that they "had data" that said that their network was being overwhelmed by bittorrent pirates. > > In fact, the problem was bufferbloat - DOCSIS 2.0 gear that was designed to fail miserably under any intense upload. The part about bittorrent piracy was based on claimed measurements that apparently were never in fact performed about the type of packets that were causing the problem. > > Hence: I know it is a quixotic thing on my part, but the scientist in me wants to see the raw data and see the methods used to obtain it. > > I have friends who actually measure Internet traffic (kc claffy, for example), and they do a darn good job. The difficulty in getting data that could provide the 70% statistic is *so high* that it seems highly likely that no such measurement has ever been done, in fact. > > But if someone has done such a measurement (directly or indirectly), defining their terms and methodology sufficiently so that it is a reproducible result, it would probably merit an award for technical excellence. > > Otherwise, please, please, please don't lend your name to promulgating nonsense, even if it seems useful to argue your case. Verify your sources. > > > > On Monday, September 19, 2016 4:26pm, "Dave Taht" said: > >> ok, I got BBR built with net-next + v2 of the BBR patch. If anyone >> wants .deb files for ubuntu, I can put them up somewhere. Some quick >> results: >> >> http://blog.cerowrt.org/post/bbrs_basic_beauty/ >> >> I haven't got around to testing cubic vs bbr in a drop tail >> environment, my take on matters is with fq (fq_codel) in place, bbr >> will work beautifully against cubic, and I just wanted to enjoy the >> good bits for a while before tearing apart the bad... and staying on >> fixing wifi. >> >> I had to go and rip out all the wifi patches to get here... as some >> code landed to the ath10k that looks to break everything there, so >> need to test that as a baseline first - and I wanted to see if >> sch_fq+bbr did anything to make the existing ath9k driver work any >> better. >> >> >> >> >> On Sat, Sep 17, 2016 at 2:33 PM, Dave Taht wrote: >>> On Sat, Sep 17, 2016 at 2:11 PM, wrote: >>>> The assumption that each flow on a path has a minimum, stable RTT fails in >>>> wireless and multi path networks. >>> Yep. But we're getting somewhere serious on having stabler RTTs for >>> wifi, and achieving airtime fairness. >>> >>> http://blog.cerowrt.org/flent/crypto_fq_bug/airtime_plot.png >>> >>>> >>>> >>>> However, it's worth remembering two things: buffering above a certain level is >>>> never an improvement, >>> which BBR recognizes by breaking things up into separate bandwidth and >>> RTT analysis phases. >>> >>>> and flows through any shared router come and go quite frequently on the real >>>> Internet. >>> Very much why I remain an advocate of fq on the routers is that your >>> congestion algorithm for your particular flow gets more independent of >>> the other flows, and ~0 latency and jitter for sparse flows is >>> meaningful. >>> >>>> Thus RTT on a single flow is not a reasonable measure of congestion. ECN marking >>>> is far better and packet drops are required for bounding time to recover after >>>> congestion failure. >>> Aww, give the code a chance, it's only been public for a day! I >>> haven't even got it to compile yet! >>> >>> I think it is a *vast* improvement over cubic, and possibly the first delay >>> sensitive tcp that can compete effectively with it. I'm dying to test >>> it thoroughly, >>> but have a whole bunch other patches for wifi in my queue. >>> >>>> The authors suffer from typical naivete by thinking all flows are for file >>>> transfer and that file transfer throughput is the right basic perspective, >>>> rather than end to end latency/jitter due to sharing, and fair sharing >>>> stability. >>> While I agree *strongly* that lots of short flows is how the internet >>> mostly operates, (I used to cite a paper on this a lot) >>> >>> a huge number of bulk flows exist that has been messing up the short >>> flows. I think the number was something 70% of internet traffic has >>> become netflix-like. *anything* e2e that can reduce the negative >>> impact of the big fat flows on everything else is a win. >>> >>> >>>> >>>> >>>> -----Original Message----- >>>> From: "Jonathan Morton" >>>> Sent: Sat, Sep 17, 2016 at 4:11 pm >>>> To: "Maciej Soltysiak" >>>> Cc: "Maciej Soltysiak" , >>>> "cerowrt-devel@lists.bufferbloat.net" >>>> Subject: Re: [Cerowrt-devel] BBR congestion control algorithm for TCP >>>> innet-next >>>> >>>> >>>>> On 17 Sep, 2016, at 21:34, Maciej Soltysiak wrote: >>>>> >>>>> Cake and fq_codel work on all packets and aim to signal packet loss early to >>>>> network stacks by dropping; BBR works on TCP and aims to prevent packet loss. >>>> By dropping, *or* by ECN marking. The latter avoids packet loss. >>>> >>>> - Jonathan Morton >>>> >>>> _______________________________________________ >>>> Cerowrt-devel mailing list >>>> Cerowrt-devel@lists.bufferbloat.net >>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>>> >>>> >>>> _______________________________________________ >>>> Cerowrt-devel mailing list >>>> Cerowrt-devel@lists.bufferbloat.net >>>> https://lists.bufferbloat.net/listinfo/cerowrt-devel >>> >>> >>> -- >>> Dave Täht >>> Let's go make home routers and wifi faster! With better software! >>> http://blog.cerowrt.org >> >> >> -- >> Dave Täht >> Let's go make home routers and wifi faster! With better software! >> http://blog.cerowrt.org >> > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel --------------4DEE2DE5B7470D7203D04553 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit On 20/09/16 21:27, dpreed@reed.com wrote:
I constantly see the claim that >50% of transmitted data on the Internet are streaming TV. However, the source seems to be as hard to nail down

I don't think the source is hard to identify.  It's Sandvine press releases.  That's what the periodic stories on Ars Technica are always derived from.

https://www.sandvine.com/pr/2015/12/7/sandvine-over-70-of-north-american-traffic-is-now-streaming-video-and-audio.html

 as the original claim that >50% of Internet traffic was pirated music being sent over bittorrent.

You recently repeated that statistic as if it were a verified fact.

I remember that in the early days of WiFi DSSS availability the claim was repeatedly made from podiums at conferences I attended that "the amount of WiFi in parking lots on Sand Hill Road [then the location of most major Silicon Valley VC firms] had made it so that people could not open their car doors with their remote keys".  This was not intended as hyperbole or a joke - I got into the habit of asking the speakers how they knew this, and they told me that their VC friends had all had it happen to them...

Propaganda consists of clever stories that "sound plausible" and which are spread by people because they seem to support something they *wish* were true for some reason.

I suspect that this 70% number is more propaganda of this sort.

In case it is not obvious, the beneficiaries of this particular propaganda are those who want to claim various things - that the Internet is now just TV broadcasting and thus should be treated that way (Internet Access Providers should select "channels", charge for allowing them through to customers, improving the "quality of programming" and censoring anything offensive, as just one example)

So I am extremely curious as to an actual source of such a number, how it was measured, and how its validity can be tested reproducibly.

Some may remember that the original discovery of "bufferbloat" was due to the fact that Comcast deployed Sandvine gear in its network to send RST packets for any connections that involved multiple concurrent TCP uploads (using DPI technology to guess what TCP connections to RST and the right header data to put on the RST packets).

Their argument for why they *had* to do that was that they "had data" that said that their network was being overwhelmed by bittorrent pirates.

In fact, the problem was bufferbloat - DOCSIS 2.0 gear that was designed to fail miserably under any intense upload.  The part about bittorrent piracy was based on claimed measurements that apparently were never in fact performed about the type of packets that were causing the problem.

Hence: I know it is a quixotic thing on my part, but the scientist in me wants to see the raw data and see the methods used to obtain it.

I have friends who actually measure Internet traffic (kc claffy, for example), and they do a darn good job.  The difficulty in getting data that could provide the 70% statistic is *so high* that it seems highly likely that no such measurement has ever been done, in fact.

But if someone has done such a measurement (directly or indirectly), defining their terms and methodology sufficiently so that it is a reproducible result, it would probably merit an award for technical excellence.

Otherwise, please, please, please don't lend your name to promulgating nonsense, even if it seems useful to argue your case.  Verify your sources.



On Monday, September 19, 2016 4:26pm, "Dave Taht" <dave.taht@gmail.com> said:


ok, I got BBR built with net-next + v2 of the BBR patch. If anyone
wants .deb files for ubuntu, I can put them up somewhere. Some quick
results:

http://blog.cerowrt.org/post/bbrs_basic_beauty/

I haven't got around to testing cubic vs bbr in a drop tail
environment, my take on matters is with fq (fq_codel) in place, bbr
will work beautifully against cubic, and I just wanted to enjoy the
good bits for a while before tearing apart the bad... and staying on
fixing wifi.

I had to go and rip out all the wifi patches to get here... as some
code landed to the ath10k that looks to break everything there, so
need to test that as a baseline first - and I wanted to see if
sch_fq+bbr did anything to make the existing ath9k driver work any
better.




On Sat, Sep 17, 2016 at 2:33 PM, Dave Taht <dave.taht@gmail.com> wrote:

On Sat, Sep 17, 2016 at 2:11 PM,  <dpreed@reed.com> wrote:

The assumption that each flow on a path has a minimum, stable  RTT fails in
wireless and multi path networks.

Yep. But we're getting somewhere serious on having stabler RTTs for
wifi, and achieving airtime fairness.

http://blog.cerowrt.org/flent/crypto_fq_bug/airtime_plot.png




However, it's worth remembering two things: buffering above a certain level is
never an improvement,

which BBR recognizes by breaking things up into separate bandwidth and
RTT analysis phases.


and flows through any shared router come and go quite frequently on the real
Internet.

Very much why I remain an advocate of fq on the routers is that your
congestion algorithm for your particular flow gets more independent of
the other flows, and ~0 latency and jitter for sparse flows is
meaningful.


Thus RTT on a single flow is not a reasonable measure of congestion. ECN marking
is far better and packet drops are required for bounding time to recover after
congestion failure.

Aww, give the code a chance, it's only been public for a day! I
haven't even got it to compile yet!

I think it is a *vast* improvement over cubic, and possibly the first delay
sensitive tcp that can compete effectively with it. I'm dying to test
it thoroughly,
but have a whole bunch other patches for wifi in my queue.


The authors suffer from typical naivete by thinking all flows are for file
transfer and that file transfer throughput is the right basic perspective,
rather than end to end latency/jitter due to sharing, and fair sharing
stability.

While I agree *strongly* that lots of short flows is how the internet
mostly operates, (I used to cite a paper on this a lot)

a huge number of bulk flows exist that has been messing up the short
flows. I think the number was something 70% of internet traffic has
become netflix-like. *anything* e2e that can reduce the negative
impact of the big fat flows on everything else is a win.





-----Original Message-----
From: "Jonathan Morton" <chromatix99@gmail.com>
Sent: Sat, Sep 17, 2016 at 4:11 pm
To: "Maciej Soltysiak" <maciej@soltysiak.com>
Cc: "Maciej Soltysiak" <maciej@soltysiak.com>,
"cerowrt-devel@lists.bufferbloat.net" <cerowrt-devel@lists.bufferbloat.net>
Subject: Re: [Cerowrt-devel] BBR congestion control algorithm for TCP
innet-next



On 17 Sep, 2016, at 21:34, Maciej Soltysiak  wrote:

Cake and fq_codel work on all packets and aim to signal packet loss early to
network stacks by dropping; BBR works on TCP and aims to prevent packet loss.

By dropping, *or* by ECN marking.  The latter avoids packet loss.

 - Jonathan Morton

_______________________________________________
Cerowrt-devel mailing list
Cerowrt-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cerowrt-devel


_______________________________________________
Cerowrt-devel mailing list
Cerowrt-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cerowrt-devel



--
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org



--
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org


_______________________________________________
Cerowrt-devel mailing list
Cerowrt-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/cerowrt-devel

--------------4DEE2DE5B7470D7203D04553--