Correct. For those (who don¹tt already know) that are interested in
learning about this, do some reading on Diplex Filters
(http://en.wikipedia.org/wiki/Diplexer) which are used to ³split² the RF
spectrum apart so that the lower portion and the higher portion can be
amplified independently, before recombining the two portions. I believe
this was done to accomplish unity gain in each direction independently.
Also, I¹d like to note that there have been a few comments in this thread
that lead me to believe some folks are confusing asymmetrical routing
paths with asymmetrical speeds. Don¹t confuse the two as they have nearly
nothing to do with one another.
-Josh
On 3/2/15, 6:00 AM, "nanog-request(a)nanog.org" <nanog-request(a)nanog.org>
wrote:
>------------------------------
>
>Message: 3
>Date: Sun, 1 Mar 2015 08:08:27 -0500
>From: Clayton Zekelman <clayton(a)mnsi.net>
>To: Barry Shein <bzs(a)world.std.com>
>Cc: NANOG <nanog(a)nanog.org>
>Subject: Re: Verizon Policy Statement on Net Neutrality
>Message-ID: <32D3C16D-0F4D-45BA-99F8-D41FE23D472C(a)mnsi.net>
>Content-Type: text/plain; charset=us-ascii
>
>Yes, so when cable modems were introduced to the network, they had to be
>designed to work on the EXISTING infrastructure which was designed to
>deliver cable TV. It's not some conspiracy to differentiate higher priced
>business services - it was a fact of RF technology and the architecture
>of the network they were overlaying this "new" service on top of.
>
>
>
>Sent from my iPhone
>
>>On Feb 28, 2015, at 10:28 PM, Barry Shein <bzs(a)world.std.com> wrote:
>>>On February 28, 2015 at 18:14 clayton(a)mnsi.net (Clayton Zekelman) wrote:
>>>You do of course realize that the asymmetry in CATV forward path/return
>>>path existed LONG before residential Internet access over cable
>>>networks exited?
>>You mean back when it was all analog and DOCSIS didn't exist?
>>>Sent from my iPhone
>>>>On Feb 28, 2015, at 5:38 PM, Barry Shein <bzs(a)world.std.com> wrote:
>>>>Can we stop the disingenuity?
>>>>Asymmetric service was introduced to discourage home users from
>>>>deploying "commercial" services. As were bandwidth caps.
>>>>One can argue all sorts of other "benefits" of this but when this
>>>>started that was the problem on the table: How do we forcibly
>>>>distinguish commercial (i.e., more expensive) from non-commercial
>>>>usage?
>>>>Answer: Give them a lot less upload than download bandwidth.
>>>>Originally these asymmetric, typically DSL, links were hundreds of
>>>>kbits upstream, not a lot more than a dial-up line.
>>>>That and NAT thereby making it difficult -- not impossible, the savvy
>>>>were in the noise -- to map domain names to permanent IP addresses.
>>>>That's all this was about.
>>>>It's not about "that's all they need", "that's all they want", etc.
>>>>Now that bandwidth is growing rapidly and asymmetric is often
>>>>10/50mbps or 20/100 it almost seems nonsensical in that regard, entire
>>>>medium-sized ISPs ran on less than 10mbps symmetric not long ago. But
>>>>it still imposes an upper bound of sorts, along with addressing
>>>>limitations and bandwidth caps.
>>>>That's all this is about.
>>>>The telcos for many decades distinguished "business" voice service
>>>>from "residential" service, even for just one phone line, though they
>>>>mostly just winged it and if they declared you were defrauding them by
>>>>using a residential line for a business they might shut you off and/or
>>>>back bill you. Residential was quite a bit cheaper, most importantly
>>>>local "unlimited" (unmetered) talk was only available on residential
>>>>lines. Business lines were even coded 1MB (one m b) service, one
>>>>metered business (line).
>>>>The history is clear and they've just reinvented the model for
>>>>internet but proactively enforced by technology rather than studying
>>>>your usage patterns or whatever they used to do, scan for business ads
>>>>using "residential" numbers, beyond bandwidth usage analysis.
>>>>And the CATV companies are trying to reinvent CATV pricing for
>>>>internet, turn Netflix (e.g.) into an analogue of HBO and other
>>>>premium CATV services.
>>>>What's so difficult to understand here?
>>>>--
>>>> -Barry Shein
>>>>The World | bzs(a)TheWorld.com |
>>>>http://www.TheWorld.com
>>>>Purveyors to the Trade | Voice: 800-THE-WRLD | Dial-Up: US, PR,
>>>>Canada
>>>>Software Tool & Die | Public Access Internet | SINCE 1989
>>>>*oo*
>>--
>> -Barry Shein
>>The World | bzs(a)TheWorld.com |
>>http://www.TheWorld.com
>>Purveyors to the Trade | Voice: 800-THE-WRLD | Dial-Up: US, PR,
>>Canada
>>Software Tool & Die | Public Access Internet | SINCE 1989 *oo*
>
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Any Charter or Comcast Network Folks out there, I would appreciate a contact off-list. I am in the charter new england territory to be transferred to comcast & am seeing unusual network issues.
Thanks,
Mitchell T. Lewis
Mlewis(a)Techcompute.Net
LinkedIn Profile: www.linkedin.com/in/mlewiscc
Mobile: (203)816-0371
A computer will do what you tell it to do, but that may be much different from what you had in mind. ~Joseph Weizenbaum
I have put this on a blog post, and my g+ also, here, and submitted
the story to slashdot and reddit. How I spend my sunday afternoons
these days!
The linky version:
http://the-edge.blogspot.com/2015/03/virgin-media-fixing-epidemic-of.html
or g+: https://plus.google.com/u/0/107942175615993706558/posts/E1yMgbWW81C
--snip snip--
To whom it may concern at Virgin Media:
My IP address is apparently now banned from accessing your site at
all, for "advertising", on this thread:
http://community.virginmedia.com/t5/Up-to-152Mb/Bufferbloat-High-Latency-am…
Believe me, I understand the degree to which advertising pollutes the
internet. And certainly, given the brevity of my post, you could
assume that I was just some random guy, selling snake oil. Nothing
could be further from the truth. Admittedly, it was a short message,
it was kind of late, and I was in a hurry, being that I have so many
other networks to help fix. To clarify matters:
I am the co-founder of the bufferbloat project, and I like to think, a
world-wide acknowledged expert on the topic on this thread.
In particular, I worked pretty hard on part of the DOCSIS 3.1
standard, which was ratified years ago, and has a specific section on
it regarding technologies that can help fix *half* your bufferbloat
problem.
http://www.cablelabs.com/how-docsis-3-1-reduces-latency-with-active-queue-m…
I admit to some frustration as to how long it is taking DOCSIS 3.1 to roll out.
The cablelabs study that led up to the AQM component in the 3.1
standard - in which I participated and am cited in, is here:
http://www.cablelabs.com/wp-content/uploads/2013/11/Active_Queue_Management…
And while I continue to favor fq_codel as the best solution for low
and medium bandwidths - I have no problem with you somehow, soon,
getting DOCSIS-pie out the door.
If you continue to exist in denial of what your own R&D department for
your own industry is saying, ghu help you! After giving this talk at
uknof, the premier conference for network operators in the UK:
https://plus.google.com/u/0/107942175615993706558/posts/immF8Pkj19C
*over two years ago*, I met with 6+ technical members of Virgin
Media's staff, who all agreed they had a problem, understood what it
was, and grokked the various means to fix it. Judging from the
enthusiasm in the room, I figured you'd be rolling out fixes by now,
but was wrong.
A rather human readable explanation of what has gone into the pending
3.1 standard is in the IETF internet draft here:
https://datatracker.ietf.org/doc/draft-white-aqm-docsis-pie/
Sadly, just DOCSIS-pie rolling out on the modems is not enough - you
have to somehow, yourselves, fix the dramatic overbuffering on the
CMTS side, as shown here:
http://burntchrome.blogspot.com/2014/05/disabling-shaping-in-one-direction-…
These downlink problems have been discussed thoroughly on the
bufferbloat.net bloat and the ietf aqm mailing lists, and rather than
point at direct links I would encourage more people to join the
discussions there, and browse the archives.
As I have seen no visible progress on the CMTS front yet...
The best way to fix bufferbloat for your suffering customers *now*, is
to help them - and your customer service departments - recognise the
problem when it occurs and propose sane ways to fix it with stuff
available off the shelf which includes the free firmware upgrades
distributed by openwrt, or nearly any linux derived product and by the
products available downstream from those.
I have no financial interest in *free firmware*. I'm just trying to
fix bufferbloat on a billion+ devices and nearly every network in the
world as fast as humanly possible. Furthermore, me and a whole bunch
of Internet luminaries gave the theory and code away for *free* also,
in the hope that by doing so that might more quickly get the megacorps
of the world to adopt them and make the quality of experience of
internet access for billions of users of the world vastly better.
Fixing bufferbloat was a 50 year old network research problem, now
solved, with great joy, thoroughly, by some of the best minds in the
business, and the answers are now so simple as to fit into a few
hundred lines of code, easy to configure for end-users and easily
embeddible in your own devices and networks if only you would get on
the stick about it.
We have provided the code, are in the standardization process, and
provided free tools to diagnose and fix your epidemic bufferbloat
accurately on every kind of device you have.
Two examples of fixing bufferbloat on cablemodems:
http://burntchrome.blogspot.com/2014/05/fixing-bufferbloat-on-comcasts-blas…http://snapon.lab.bufferbloat.net/~cero2/jimreisert/results.html
And the *free* tool designed not only to accurately measure
bufferbloat, but one that you can setup internally to test your
networks and devices for it privately and quietly and then fix them
with, is here:
https://github.com/tohojo/netperf-wrapper
So, now, a rant:
Now, if me pointing a customer of yours that has correctly identified
the root cause of his own problems, at the solutions both available
now, and pending, is considered "advertising", then there really is an
orwellian mixup between the definition of that word, and the truth, on
your side of the water.
Please, unblock my dtaht account and unblock my IP, and allow in
better information about how customers of yours can solve the
incredibly serious, and incredibly epidemic problem of bufferbloat.
... A problem that is now easy to solve with cheap gear now all over
the market so that all your customers suffering can fix it for
themselves if they so choose.
And: I would like a public apology for blocking me, and a clear
statement from Virgin, as to how, when, and where, they will begin to
roll out their own fixes to bufferbloat across their subscriber base.
And perhaps, you could publish some guidelines - like accurate
up/download settings to use - to help your customers fix your problems
for themselves.
Sincerely,
Dave Taht
Co-founder, bufferbloat.net
--
Dave Täht
Let's make wifi fast, less jittery and reliable again!
https://plus.google.com/u/0/107942175615993706558/posts/TVX3o84jjmb
