Slashdot Mirror
Copper Wire As Fast As Fiber?
Krishna Dagli writes to tell us that a new consortium of hardware vendors and phone companies have banded together in order to try for fiber optic speeds over copper wiring. From the article: "To avoid interference, current DSL implementations use static spectrum management that is built for a 'worst-case' scenario. Most actual phone lines would allow for far better performance, and DSM technology will allow each DSL connection to be regulated in real time by the hardware based on measured crosstalk and on current data needs of each customer. The end result could be DSL connections that top out at 100Mbps or more."
But when will it hit my doorstep at a reasonable rate?
All this talk of speedy internet access is great, but I'm still not seeing much benefit when it comes to what my ISP offers.
Copper Wire as Fast as Fiber? What a misleading topic. How about 'Copper Outside Plant can rival current FTTH speeds,' as this is much less inflammatory and more on target with what is intended to be said. With such a general topic there's no telling what the story is actually about, and in this case, it's not any of the following:
-Copper Outside Plant transmits data at OC-192 speeds
-Lab makes Copper transmit OC-48 speeds
-Copper Wire discovered to have same frequency versatility of fiber
-Police Cables allow bacon to move at speed of light
Sheesh.
love and peace
-cheez
it is hard enough getting ISP's (in this case those dirty theiving telco's) to pony up the actual bandwith advertised on a simple 1.5Mbps DSL line. I might be able to get 100Mbps to the DSL suboffice but I seriously doubt that ISP's would be willing to pay for the connection further down the line to actually provide that kind of speed to anything outside their local network. ISP's tend to oversell bandwith and hope for the best.
It's not likely we'll see this very soon. As soon as Ma Bell gets their hands on this, they'll blunder it as usual and blame everyone else for their problems... If they are successful, you can bet that you'll get high download speeds, but will be locked up with that lovely 256k uplink. Oh, you want more? That's a 'business line', you get to pay triple!
By increasing the capacity of copper to (best case) 100Mps they are only prolonging the inevitable. Fiberoptics has an upper limit that is immensely higher...
No. They're using hardware to monitor when the conditions are worst-case. It's obviously better than assuming the conditions are always as bad as they could possibly be.
ResidntGeek
So, in other words there's a technology to make existing infrastructure MUCH more efficient. Don't hold your breath waiting for it. DSL is owned by whom? The monopoly telephone companies, and with the recent court rulings that say they don't HAVE to sublease it is not likely there will be 1:1 competition in the near future. My guess is that the phone companies will see this as an excuse to raise prices, due to perceived value*, rather than to provide improved performance that competes with cable at a similar, or lower price.
*Just as CDs cost less to manufacture than cassette tapes, but until recently sold for more $$, such as it will be with "extreme DSL" (or whatever they call this service).
The article title implies that a copper wire can have more bandwidth than a fiber. Read on:
See the switch in argument? From "copper > fiber" in the title (and other locations within the article to boot) to "copper*50 > fiber*1". I'm sure if I bundle 10,000,000 twisted pairs then I can out-bandwidth a single fiber any day, but does that mean I should say copper is faster than fiber?
It's like titling my article "3.5 inch floppies hold more than a hard drive?" but then say if I combine 2 billion floppies in parallel then I get 3 TB of storage where as a single hard drive only holds 700 GB.
Apples and oranges.
That said, I think the article is trying to point out that the existing copper can be better utilized and achieve higher bandwidth than if a new, single fiber were trenched in its place. I see little controversy in this. But this does not mean "copper > fiber".
I have to admit that this is probably one of the most confusing and poorly written Ars article I've ever read.
:wq
Well, it's all depending on your sense of scale.
The propagation velocity of an electrical charge down a conductive wire is a significant fraction of the speed of light. In most cases, this might as well be the speed of light, because it's so much faster than anything else that we do, or work with. (The current doesn't actually flow at the speed of light, because not all the electrons are moving in a straight line down the wire. So even though the electrons are moving at the speed of light, the net velocity of the charge is some fraction thereof.) Something sticks in my mind about electricity usually propagating at around 0.3c, but I can't substantiate that.
However, light travels down a fiber optic cable at, unsurprisingly, the speed of light. This can be anywhere up to 3x faster than a signal moving down a conductive cable, depending on the properties of the fiber and the cable.
So while light is significantly faster than electricity, for all practical purposes today, they're both "really, really fast;" the limitations to data capacity arise for other reasons, mostly related to bandwidth, and not because of the time that the signal takes moving down the wire.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
It's the width of the tubes that matter, since the current is all the same speed inside them. ;)
'Sensible' is a curse word.
I have a couple of concerns with the direction this article takes.
1. To say that any money spent on FTTH is money wasted due to the potential of this completely untested technology is really unfair to say the least. At this point we do not know if the new tech will even provide results. Also, there are many places that really do have terrible copper, especially in the consumer markets. Many old homes and apartments have copper that cannot even use current DSL, let alone attempting to use an even more intensive signal.
2. At the beginning of the article the person paints a picture of a guy going to his boss to tell them that we may have made a mistake in going with this FTTH idea. This is about the dumbest thing this person could do because a) The decision is made and cannot be undone and b) if the boss is not putting pressure on you do not bring up things that you cannot do anything about which will get your ass in trouble. It is never a good idea.
I can see where the person is coming from. We should be honest and come forth and say we should do this, even though we initially thought we should of done and did do that. Unfortunately our corporate climate has never been overly friendly to brute honesty. The last thing you want to do is stand up in a loud voice admitting guilt to the problem. It is like saying, "Well I ment to get it done, but x, y, and z happened." Sorry but ment to and what actually happened are two entirely different problems. Now your SOL.
Brendan
You see, the internet is like a stream in the woods.
Water in the Amazon river and a stream may travel at the same speed, but the Amazon moves a heck of a lot more water in a given period of time than the stream. This difference is analogous to bandwidth. Electrical signals and light signals both travel at essentially the same speed (though I believe there is actually a small difference in the real world), but fiber can carry a lot more data than copper.
I did my own test to see if copper wire was a fast as fiber.
Day One
Ate a bowl of fiber. Bowel movement within two hours. Pretty fast.
Day Two
Ate a bowl of copper wire. Severe internal bleeding.
Ultimately, results were inconclusive as the emergency surgery on day two negated any possible effects of the copper wire.
Unknown host pong.
A physical limitation to any transmission medium is the propagation delay from one point to another. Sure, you may get the same unidirectional transfer rate with copper compared to wire (which I doubt considering the possible frequencies involved), but bi-directional communication will be hampered by the propagation delay, in which fiber obviously has the upper hand. There are other issues regarding the resistance of the medium, forcing you to add repeaters periodically, but I digress for now.
Note: electrical signals do *not* propagate at the speed of light through copper.
OTOH, http://www.itarchitect.com/article/NMG20010416S000 6 states:
So don't take it for granted that just because an electric signal doesn't travel at c in copper that it's slower than light in fiber!
On a barely-related tangent: As someone who put up with a satellite internet connection for 4 years, I can state authoratatively that the speed of light isn't nearly quick enough for a variety of purposes....
Even if the fiber that's being taken out to your curb can take 100Mb/s, if they don't think there's a market for it, they probably aren't buying the backhaul capacity to provide that level of service.
In other words, they might be able to get you hooked up at 100Mb/s, but you'd only be able to talk to your neighbors and other people on the local subnet at that speed.
This is a real problem for almost all broadband ISPs, because they're just not buying the capacity from their Tier 1 ISP that they should be, in order to offer even the speeds that they're advertising to people. "Real" internet connections -- and by that I mean ones to upper-tier ISPs with bandwidth and QoS and uptime guarantees -- are not cheap, and thus they get skimped on.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
... here we can get 16 mbit dsl for ~60 euro together with a telefon flatrate. But it's of little use since your upload is 1 mbit. You can't really use your big pipe since most servers won't give out data that fast. And distributed networks which could saturate this pipe won't work because one is not able to feed back that fast and so you're stuck on 1-2 mbit down (e.g. bittorrent).
So it's great that they're testing new technologies but the real bottleneck isn't bandwith to the costumer but their ability to send data.
Okay, this comparison seems rather slippery upon first glance. Let's break it down so we are clear on what they are attempting to communicate to us:
So again, I went to wikipedia to check the actual bandwidth of current optical fiber communications and learned that recently speeds of 14tbps (thats terabits-per-second) have been reached over distances of 140km. This leads me to the conclusiong that while the currently installed FTTH switches could be limited to doing 2.5gbps (per 50 homes apparently? regardless..it doesn't really matter), which is by no means the limit of fiber-optic communication. 2.5gbps was the limit of third-generation fiber-optic communications (during the 1980's).
Now lets take a moment to revisit the title of this article, "Copper Wire as Fast as Fiber?"; This article seems like a bunch of "FUD" to me.
--Battlefield 2, anyone?
Censorship is obscene. Patriotism is bigotry. Faith is a vice. Slashdot 2.0 sucks.
The price of copper has gone from $0.25 a pound to $3.50 a pound in the last 5 years.
The copper -vs- fiber debate almost ended in 2000 because fiber is such a superior data transmission medium.
The copper -vs- fiber debate is completely over for new installations.
The material cost is on par now, and the primary cost of the installation is not the material but the labor.
If voting were effective, it would be illegal by now.
Copper and fiber - much better for security purposes than wireless; but most of us don't really need the added protection. Wireless encryption should be able to make my data harder to steal than it's worth in most cases. I'd like to take this opportunity to tell both the telcos and the cablecos to diversify their network divisions - that physical connection is becoming as useful as the human appendix (except for certain special cases).
"Fast" can refer to either bandwidth (how much data the pipe carries at one time), or latency (the delay between when a signal is sent and when it is received). Here, they're talking about bandwidth.
But as other have pointed out, the summary is QUITE misleading. Copper wire of a given spec (length, guage, etc.) has a maximum theoretical bandwidth. The actual bandwidth we get out of it depends on the aim and sophistication of the signaling mechanism. My 3.0 MBps DSL line uses the exact same copper pair of phone wires as a dial-up 56k modem would, but it achieves much greater bandwidth because it crams more signal onto the wires. For last-mile distances (which may be more or less than a mile, obviously), the current practical maximum is much higher than current DSL rates, but we would have to use a more sophisticated signaling mechanism than DSL does.
Optical fiber has similar theoretical limits, governed by length and cable spec, and similar practical limits depending on how the signaling works. If we're talking about realistic cable guages and last-mile distances, optical fiber will always have a higher theoretical bandwidth than copper wire--that's just physics.
HOWEVER... since the practical maximum is governed by the signaling technologies in use, the theoretical maximums don't really matter.
...in a Jimmy Cagney voice: "Nyah! You'll never catch me, copper!"
When I first got a cable connection, in late 1997, the modem was $300, the installation fee was $150 or so, and the monthly fee was $50. I had a static IP address and the only limitation on my bandwidth up and down was the local application or remote server's ability to feed the data into the 'net, so far as I could tell.
Then some of my neighbors starting getting a cable modem...
Now it's all different. But the interesting point is that the cable modem is about 1/3 the price, there is usually no installation fee, and the monthly fee is still $50, despite 10 years of inflation. DSL is typically even less. In other words, the main development in broadband over the past 10 years has been a fall in the real price and a lot more people using it. (I'd say, personally, it's also a bit more reliable -- in '97 the cable net connection would flake out for an hour or so every few days. Now it almost never does. But that's just one operator, YMMV.)
Had we wanted, instead, faster and better service at the same real price (e.g. $75/month in 2006 dollars), then maybe we'd have got that. But that is apparently not what our buying habits told the cable and DSL operators we wanted.
You can shove more data over fiber, by several orders of magnitude, given enough equipment at the end-points. Copper only has a few hundred megaherz worth of useable frequency spectrum and that coupled with the noise floor and signal to noise ratio (SNR) puts an upper limit on how much data you can push over it. You can't just pump in higher voltages to improve the SNR because even with variable-sized twisted pair you will get noise leaking into adjacent wires.
The issue with fiber is that getting the several orders of magnitude improvement in bandwidth requires increasingly expensive equipment at the end-points. This is fine for long-haul fiber but obviously not appropriate for a consumer end-point. Fiber gets multiplicative bandwidth improvements by transmitting light at different frequencies all over the same physical fiber optic cable. Specialized chips can pick-off the frequencies and split them into individual transceivers. A consumer end-point could decode one of those frequencies fairly cheaply, but not much more then that before the equipment becomes expensive. This is certainly viable... the head-end can transmit dozens of frequencies over the fiber and the distribution point on the pole can split it out to homes, or even just route it over shorter-haul copper in proximity to the home (which is probably a lot cheaper then running fiber all the way into a home).
-MattActually in some other discussions I've said that I think this could be really beneficial -- with systems like BitTorrent, and to a lesser extent Skype and other P2P systems, it's conceivable that a big broadband provider could configure its network so that a lot of "bulk" traffic was kept on its own wires, and didn't have to traverse the public net.
For example, if they provided a Skype supernode that all the broadband users could connect to, whenever one of the customers wanted to call another, the routing could all be done without having to send packets through a peering/transit point. It would all be on the ISPs network, which costs them basically nothing.
You can make similar arguments for positioning cache servers for other types of stuff on the network. Were it not for the copyright concerns, they could probably save themselves a lot of customer aggravation and bandwidth expense, if they just did some intelligent caching of bittorrent traffic. (And it's my understanding this is the whole theory behind the Cache Discovery Protocol, but I'm not sure which ISPs are going to use it.)
The place where I think this could have the biggest effects, would be in places that have large networks that are basically isolated from the public net by narrow connections -- say, Australia. A system of intelligent caching and encouraging the use of P2P applications would probably lighten the load on the traffic actually passing in and out of a "network island" by favoring internal connections instead.
So a broadband ISP that let you connect to your neighbor at 100Mb/s but only pass packets out to the public 'net at 1Mb, might at some point in the future, if it was designed correctly, seem like a really sweet deal.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Next time you claim something runs at Fiber Speeds, make sure it hits at least 1Gbps, please.
Disagreeing with me does not mean you get to mod me troll.
There's a lot of wire in the ground already.
And it doesn't matter how much it would cost to buy a pound of copper, if you already own it and already have installed it, it's cheaper to use it than to install fiber.
There's always money in making already installed cables work better to avoid installing new ones.
http://lkml.org/lkml/2005/8/20/95