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Cloudburst: 10 Gbps Achieved Over Standard Copper Telephone Wire

Bell labs just announced that they have achieved 10Gbps over POTS lines for 30M.

Bell Labs, which is owned by Alcatel-Lucent, hit a speed of 10Gbps inside its own laboratory using two pairs of 30m long standard telephone cables to set the mark. “It will enable operators to provide internet connection speeds that are indistinguishable from fibre-to-the-home services, a major business benefit in locations where it is not physically, economically or aesthetically viable to lay new fibre cables all the way into residences," said Alcatel-Lucent, according to the BBC. "Instead, fibre can be brought to the curbside, wall or basement of a building and the existing copper network used for the final few metres."

Fast but short. True, but they also demonstrated a bidirectional 1Gbps for 70M also. What's the big deal, you say, I have gigabit myself?

This is big news because being able to use existing POTS without new provisioning greatly accelerates deployment of higher capacity broadband, since most of the expense lies in the so called 'last mile' to the customer premises. Though 70M does not a mile make, it doesn't require them to run fiber to every private dwelling.

"70M does not a mile make"

Well, that's an understatement.

It's literally like claiming "4 pennies does not a dollar make"

That said, I see the point made about reducing cost/complexity of bringing fiber inside of the home. I do wonder how much the equipment will cost to do this super-giga-DSL.

Well, that's an understatement...

Yes, it was. Looking back I see that it may have been presumptuous of me to include a industry term-of-art without citation (tho it was 'quoted' when first introduced). So without further adieu, here is the wiki for 'last mile':

The last mile or last kilometer is a phrase used by the telecommunications, cable television and internet industries to refer to the final leg of the telecomunications network... The word "mile" is used metaphorically; the length of the last mile link may be more or less than a mile.

Hopefully its clear now that when I said 'Though 70M does not a mile make', I was explicitly and intentionally using the literal sense of mile against the figurative one; as a non-condescending way of gently guiding any readers not familiar with that usage, to the realization the term should not be considered an absolute metric. Too gently apparently.

Never did I intend the 'Rukmini is randomly making a true but obvious statement' that you perceived.

Finally, though tangental to my defense, and only for completeness sake, the statement

It's literally like claiming "4 pennies does not a dollar make"

is quite literally false. Expanding the pronoun yields

Claiming '70M does not a mile make' is literally like claiming '4 pennies does not a dollar make'.

And in the same way that a 'Cat' cannot ever be literally like a 'Dog', your statement must be literally false, a priori, due to the use of simile.

Now figuratively, thats a whole different ballgame. :)

This doesn't mean people will be getting 10gbps service, but it means ISP's can offer higher speeds on the copper. If they can run 1gbps bi-direction for 70m, should be able to knock that down to say, 200mbps, and go further than 70m

Will pay for more verbal jousting!

I would just be tickled if my ISP delivered the bandwidth I already pay for.

Supposedly, I should be seeing 50 Mbps down and 20 Mbps up, but this is more what I experience:

Summary: until ISPs figure out how to deliver modest bandwidth to current capacities, talk about fiber or Gigabit speeds are silly.

PS. I hate my ISP. Don't get me started.

That's an SLA violation if I've ever seen one! Your jadedness is understandable. What do you got, FIOS or Google Fiber or ATT, or?

I have Cox Communications, and only worse options as alternatives. Google fiber is a pipe dream.

Funny, I'm on Cox and I have much better speed:

Seeing that puts me in the mood to punch something.

Seeing that puts me in the mood to punch something.

Just punch a hole thru your firewall to let off some steam, if you need.., bi-directional, multi-protocol, whatever it takes to feel better.

Now question, how much does your bandwidth vary from best to worse? Is it clearly time of day correlated? If its random then maybe its solvable by cable guy, if its the usual 8:00 PM rush-hour traffic, then its probably too many neighbors sharing the line to the aggregator.

In that case this Bell thing would be of aid, because then you could stop sharing your 'last mile' with everybody on the block and instead use your own POTS to get to the fiber transceiver...

Whatever you do, don't go out and buy a Docsis modem and uncap it to 30Mbps.. Sure its fast but its just not fair to the cable company... :)

Whatever you do, don't go out and buy a Docsis modem and uncap it to 30Mbps.. Sure its fast but its just not fair to the cable company... :)

Cap it? The ISP caps bandwidth, not the modem.

Channel configuration Downstream throughput Upstream throughput
Number of downstream channels Number of upstream channels DOCSIS EuroDOCSIS
4 4 171.52 (152) Mbit/s 222.48 (200) Mbit/s 122.88 (108) Mbit/s
8 4 343.04 (304) Mbit/s 444.96 (400) Mbit/s 122.88 (108) Mbit/s
16 4 686.08 (608) Mbit/s 889.92 (800) Mbit/s 122.88 (108) Mbit/s
24 8 1029.12 (912) Mbit/s 1334.88 (1200) Mbit/s 245.76 (216) Mbit/s

Maximum raw throughput including overhead (maximum usable throughput without overhead).

Version Downstream Upstream
Channel configuration DOCSIS throughput EuroDOCSIS throughput Channel configuration Upstream Throughput
Minimum selectable number of channels Minimum number of channels that hardware must be able to support Selected number of channels Maximum number of channels Minimum selectable number of channels Minimum number of channels that hardware must be able to support Selected number of channels Maximum number of channels
1.x 1 1 1 1 42.88 (38) Mbit/s 55.62 (50) Mbit/s 1 1 1 1 10.24 (9) Mbit/s
2.0 1 1 1 1 42.88 (38) Mbit/s 55.62 (50) Mbit/s 1 1 1 1 30.72 (27) Mbit/s
3.0 1 4 m No maximum
m × 42.88 (m × 38) Mbit/s m × 55.62 (m × 50) Mbit/s 1 4 n No maximum
n × 30.72 (n × 27) Mbit/s

The ISP caps bandwidth thru the modem.

When I've had cable internet they didn't let you own/install your own modem. Or even access its web page. Did it change? If they don't own any CPE how do they efficiently enforce throttling from the ass end, without impacting the shared media on the street? Not saying it hasn't changed, just wondering how they pulled it off?

Not sure how they limit bandwidth but they started allowing the customer to purchase their own cable modem at least 5-6 years ago. I owned my Docsis 1.1 modem, my replacement Docsis 2.0 modem and now my Docsis 3.0 modem. Cox does rent modems - typically for $7/month for a single-band Netgear and $10 for a dual-band (last I knew it was the Motorola SBG6580 but it appears they've switched to Netgear).

Evil Genius Cable Companies!

So yeah it's your DOCSIS 3.0 modem, and the modem can be openly configured however desired. But guess what? You have to come thru on the coax interface to control all the modem's parameters! When you establish a link, the first thing they do is install their config file onto your modem and re-init. Their config file has parameters that pertain to "their" side. This is how they control bandwidth before it hits their "pipe". From DOCSIS on wiki:

The customer PC and associated peripherals are termed Customer-premises equipment (CPE). The CPE are connected to the cable modem, which is in turn connected through the HFC network to the CMTS. The CMTS then routes traffic between the HFC and the Internet. Using the CMTS, the cable operator (or Multiple Service Operators - MSO) exercises full control over the cable modem's configuration...

Your connection looks like its approaching the theoretical limit though :)

OK, name an ISP that doesn't exert control over bandwidth and speed.

And yes, I am approaching the speed capability of one channel. However I do have four channels available so my theoretical limit is 108Mbps, which not coincidentally corresponds to the speed claim of Cox's highest tier, Ultra (100Mbps).

Then again, you can always wait for Docsis 3.1, that supports download speeds up to 10Gbps and upload speeds to 1Gbps. Can anyone say "Let's watch multiple 4k videos at once"?

OK, name an ISP that doesn't exert control over bandwidth and speed.

No, I don't think I should. The mere fact that you are asking that exact question indicates a disconnect. It is phrased as if the last thing I said to you was "Carl, the only thing that sets bandwidth is autonomous cable modems, ISP's are not involved, the cable modems decide on their own, by commitee..."

But just to "recap", you said was:

Cap it? The ISP caps bandwidth, not the modem

I said

The ISP caps bandwidth thru the modem.

Then I did some research and found out that, yes indeed, you may own your modem, but your ISP can configure YOUR modem anyway they want, just because they are connected to the coax side of the interface.

So I agree with you: all ISP's exert control over bandwidth and speed. The unresolved issue is how, and the question would now be: Do you now agree with me and will retract the second half of your statement above ("not the modem"). Or would you like to propose a different mechanism that ISP's use to exert control? Telekinesis, perhaps?


By the way, how good is your wiring? How old is your Cable Modem? I rewired my house in 2009 with high-quality splitters and Quad Shield RG6, paying strict attention to balancing out the line levels. In 2013, I bought a Docsis 3.0 Cable Modem.

Before I replaced the Cable Modem, I was getting download speeds of ~12Mbps. Granted, Cox has "upped" our speed at least once since I replaced the Cable Modem - before the last "upgrade", I was getting ~24Mbps, so the combination of factors are all working for me.

Docsis 3.0 definitely increased my speeds but the big change I noticed was consistency. With my Docsis 2.0 modem,running a series of tests yielded results that varied as much as 50%. Docsis 3.0 yields much more consistent results:

Thanks for the tips, Carl.

I have a DOCSYS 3.0 modem too, that is hard plumbed to a gigabit router, which my PC is hardwired to (not wifi). I have no cable TV, just internet, so it's a straight shot from the modem to my demarc - no splitters, just a wall plate.

Hmmmm. I have an older Linksys WRT54G, which I'm going to replace soon because I have to reboot it at least once a month - it doesn't lose wired connections but wireless gets "flaky". I also have a cheap Linksys 100Mbps 4-port switch in my living room that splits the single CAT6 from my office to the computer, TV and PS/3. My main computer is in the living room. My wife, as always, was not amused when I bought a "gamer" computer and told her I wanted it displayed on the 60" screen ;-)

By the way, my Cable Modem is a Motorola SB6121 Cable Modem and I actually bought it in 2012. Fuzzy memory....

Of related interest: I participate in Cox's customer surveys regularly. The last one was around a month ago and had to do with internet. From the gist of the questions, it appeared they are considering providing up to 1Gbps to the home. Right now, I only have a "middle" tier (Cox Preferred) of internet service, which supposedly provides "up to 25Mbps download speed". Obviously, I'm getting better results than that, at least at this hour of a weekday night.

"Premier" ups that to 50Mbps and "Ultra" ups it again to 100Mbps. Both, of course, at a substantially higher price than the $55 I'm currently paying.

I have had almost no problems with Cox HSI since I started with them in the 90's. Now their other services are a different story. 200+ channels of nothing to watch is a joke and I could do away with 75% of them and not miss anything except the high bill each month.

Here's a screen shot of my Cable Modem's signal page:


Take a look at your modem's signal page and see what your levels are. My Motorola's IP address is Yours may be different. Signal levels should be -15dbmv to +15dbmv and SNR should be >30db. Cable Modems will choke on signal levels that are both substantially lower and substantially higher than that.

Also, check your Bonding Channel values. If you only have one channel, your theoretical download speed is limited to 38Mbps but traffic from other users on your node may cut that appreciably. That's why my speed tests became much more consistent when I replaced my Docsis 2.0 modem with a Docsis 3.0 modem. The modem should choose which channel(s) have the lowest usage.

In my area cable company would like to see -10 to +10 dbmv


That pretty much jibes with what DSL Reports recommends. They have a couple of primers Here and Here.

The consensus seems to be that SNR is actually more important than signal level, although levels that are out of range can also cause problems. It's also agreed that too high is as bad as too low.

There are many possible fixes. I've found it best to tighten all "F" connectors a bit tighter than finger tight. Loose connections cause signal loss and leakage. I also use compression connectors wherever possible and pay attention to continuity. Also check any splitters and make certain they are rated to at least 1GHz.

A lot also depends on what control you have over premises wiring. I've lived in apartments that had extremely poor (and often old) wiring. Many older buildings still have RG59, which severely attenuate the high frequencies cable uses (note my downstream is ~850MHz). I've also seen buildings where they still use common trunks from apartment to apartment with tapoffs at each apartment or room. Without home runs, you are basically at the mercy of everyone else along the chain to have good connections.

The first thing to check is the modem signals. Although my Motorola SB6121 uses, other brands may be different. As I understand it, other common addresses are and (though many routers use that).

Another possibility is to have Cox "re-provision" your Cable Modem. They may balk at that but persistence pays off. It also pays off if you are not getting the speeds you are paying for. If your signal levels and SNR are well within spec and re-provisioning doesn't solve your slow speed, it may be time to become a "squeaky wheel".

I've occasionally had to accelerate signal problems over the years. Usually, Cox is responsive but a couple of times I've had to demand to speak to a Supervisor. Once, I even wound up contacting my city's Franchise Department (the one that is responsible for services). In that case, multiple calls to Cox had yielded no results. A conversation with the city's Franchise Department finally pushed Cox to send a Supervisor out with a meter that measured signal levels and SNR on the system. A few weeks later, Cox repaired their entire neighborhood system.