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Squeezing More Bandwidth Out of Fiber
EigenHombre writes "The New York Times reports on efforts underway to squeeze more bandwidth out of the fiber optic connections which form the backbone of the Internet. With traffic doubling every two years, the limits of current networks are getting close to saturating. The new technology from Lucent-Alcatel uses the polarization and phase of light (in addition to intensity) to double or quadruple current speeds."
Well, we'll just have to hope that their competitors will implement the technology; because the odds of Alcatel doing a proper job are pretty much zero....
Reverse the polarity! Phase variance!
add color, use 256 identifiable colors then send those, send bytes instead of bits.
If you pump too much data into a fiber optic glass, it will begin to flow under the photonic pressure similar to glass in old church windows. If you look at them, the bottoms are much thicker than at the top. The reason? All that knowledge from God in Heaven up in the sky exerts a downward pressure on churches in particular warping their window glass... the same thing will happen to fiber optics. If you put too many libraries of congress through it, it will start to flow like toothpaste and your computer rooms will have a sticky floor and all your network switches will be gooey.
Thanks
Signed,
Mr KnowItAll.
(Happy Thanksgiving by the way)
Why don't we just make the speed of light faster?
Mod parent up! it's so unlikely, it MUST be true.
Karma: Excellent. 15 moderator points expire sometime.
Isnt some large percentage of the fiber not being used anyways? Rather than change the equipment on the current fiber, why not use more of the current equipment, and light up more fiber?
Assuming we have 5 THz of usable bandwith (limited by todays fiber and optical amplifiers),
and applying some technology known from radio for quite some time:
Advanced modulation (1024 QAM): 10 bits/sec
Polarization diversity (or mimo 2*2) by 2
So, 100 Tbit/sec is approximate reasonable limit for one fiber.
There is some minor work to transfer technology from experimental labs to the field,
but this is just matter of time.
Wavelength mupltiplexing just make things a bit simpler:
Instead of one pair of A/D converters doing 100 Tbit/sec, we might use 1000 of them doing 100 Gbit/sec.
In 2010, speed above 60 Tbit/sec was already demonstrated in the lab.
Eh, will we say soon: "Life is too short to surf using 1 Gbit/sec"?
The last time I tried squeezing more bandwith out of fiber, I was constipated for weeks!
Try the veal!
I thought the point of getting fiber was so that you didn't HAVE to squeeze. My doctor and my network engineer told me so!
Cap everything -> Profit !!
You find each time go go up an order of magnitude in bandwidth, the next order matters much less.
100 bps is just painfully slow. Even doing the simplest of text over that is painful. You want to minimize characters at all costs (hence UNIX's extremely puthy commands).
1 kbps is ok for straight text, but nothing else. When you start doing ANSI for formatting or something it quickly gets noticeably slow.
10 kbps is enough that on an old text display, everything is pretty zippy. Even with formatting, colour, all that it is pretty much realtime for interactivity. Anything above that is slow though. Even simple markup slows it does a good bit. Hard to surf the modern Internet, just too much waiting.
100 kbps will let you browse even pretty complicated markup in a short amount of time. Images also aren't horrible here, if they are small. Modern web pages take time to load, but usually 10 seconds or less. Browsing is perfectly doable, just a little sluggish.
1 mbps is pretty good for browsing. You wait a bit on content heavy pages, but only maybe a second or two. Much of the web is sub second loading times. This is also enough to stream SD video, with a bit of buffering. Nothing high quality, but you can watch Youtube. Large downloads, like say a 10GB video game are hard though, it can take a day or more.
10 mbps is the point at which currently you notice no real improvements. Web pages load effectively instantly, usually you are waiting on your browser to render them. You can stream video more or less instantly, and you've got enough to stream HD video (720p looks pretty good at 5mbps with H.264). Downloads aren't too big an issue. You can easily get even a massive game while you sleep.
100 mbps is enough that downloads are easy to do in the background while you do something else, and have them ready in minutes. A 10GB game can be had in about 15 minutes. You can stream any kind of video you want, even multiple streams. At that speed you could stream 1080p 4:2:2 professional video like you'd put in to a NLE if there were any available on the web.
1 gbps is such that the network doesn't really exist for most things. You are now approaching the speed of magnetic media. Latency is a more significant problem than speed. Latency (and CPU use) aside, things tend to run as fast off a network server as they do on your local system. Downloads aren't an issue, you'll spend as much time waiting on your HDD as the data off the network in most cases.
10 gbps is enough that you can do uncompressed video if you like. You could stream uncompressed 2560x1600 24-bit (no chroma subsampling) 60fps video and still have nearly half your connection left.
If we get gig to the house, I mean truly have that kind of bandwidth available, I don't think we'll see a need for much more for a long, long time. At that speed, things just come down at amazing rates. You could download an entire 50GB BD movie during the first 6 minutes of viewing it. Things stream so fast over a gig that you can have the data more or less immediately to start watching/playing/whatever and the rest will be there in minutes. The latency you'd face to a server would be more of a problem.
Even now going much past 10mbps shows strong diminishing returns. I've gone from 10 to 12 to 20 to 50 in the span of about 2 years. Other than downloading games off of Steam going faster, I don't notice much. 50mbps isn't any faster for surfing the web. I'm already getting the data as fast as I need it. Of course usages will grow, while I could stream a single 1080p blu-ray quality video (they are usually 30-40mbps streams video and audio together) I couldn't do 2.
However at a gbps, you are really looking at being able to do just about everything someone wants to for any foreseeable future in realtime. I mean you can find theoretical cases that could use more but ask yourself how practical they really are.
I'm sure this will make my 768kbps down and 512kbps up seem so much more snappier.
This was under development before the dot com bust because back then we were going to run out of bandwidth within 3 years.
I'm down with polarity, but what is a phase of light and what does it mean to use 4 of them? Google isn't giving me any love on that.
The idea looks plausible but there is a way to upgrade bandwidth that ALWAYS works. INSTALL MORE CABLE!!!
Nice work they're doing, but nothing is going to get us around the need for new infrastructure. As much as the telecos are trying to deny it, we are going to need another major round of long distance fiber installations before the global network anything like stabilizes. Actually, I would draw a comparison to the British railway system in the 19th century (flawed but some interesting points in it), particularly with reference to the boom bust cycle (including apparent over construction early on that actually goes over capacity quite soon, and eventual REAL massive over investment and big collapses and consolidation). Not really sure if we want that outcome, but it seems like a reasonable parallel in some ways; on the one hand massive overbuilding would be nice for users, for awhile at least, but as it is we need to be breaking telecom monopolies, not creating more through collapses and consolidtation...
People are still getting video feeds by HTTP. Multicast was supposed to save on bandwidth for things like IP TV. But it still isn't happening on any real scale. A lot of core infrastructure bandwidth could be reduced by making multicast fully functional and using it. And, of course, we need to do that in a way that precludes some intermediate business deciding what we can, or cannot, receive by multicast. Oh, and how many multicast groups are there? And how do I get one?
now we need to go OSS in diesel cars
"I've gone from 10 to 12 to 20 to 50 in the span of about 2 years."
fuck you.
every day http://en.wikipedia.org/wiki/Special:Random
Pure bull shit - just use another colour
So you are saying I probably shouldn't tell you that because of how they handle business class accounts, I actually get more than that most of the time? :D
http://www.speedtest.net/result/985434853.png
That is my actual result from a few minutes ago. It is fun for bragging rights, I'll say that. However truth be told other than Impulse and Steam downloads I notice no difference over 20mbps. Personally I'd take 20/20 if it were offered instead of 50/5. However currently they use 4 downstream channels with DOCSIS 3, but only one upstream channel. The equipment can handle 4 upstream channels, Cox just doesn't use more than one.
It makes sense both in economic and practical terms to squeeze as much out of the fiber we have before laying new stuff. Not only does that get more bandwidth easier and cheaper now, but it means when new stuff is laid it'll last longer. It is real expensive to lay a transatlantic cable (and those are what are the most full). The more we can get out of one, the better. I'd much rather we research the technology to get, say, 100tbits per fiber out of the cable and need a couple thousand fibers spanning a few cables than be happy with 1tbit per fiber and need millions of fibers spanning thousands of cables.
New infrastructure should be the last resort, not the first one. Make the most efficient use of what you have, then build new stuff if there is a need. You can look at it from economic, reliability, environmental, or really any way and it comes out the same: Make better use of what you have, don't go get new things if you can avoid it.
With traffic doubling every two years, the limits of current networks are getting close to saturating.
That's ok, we have been following Butter's Law for quite some time, just like Moore's Law following transistor density. To cost of sending data halves every 9 months, and data networks double in speed every 9 months. This is well within the problem with the traffic doubling every two years.
The article implies that it's easy to do, there was simply never a need before. I seriously doubt that it's a trivial thing to accomplish a four-fold increase in bandwidth on existing infrastructure.
Polarization has a habit of wandering around in fiber. Temperature and physical movement of the fiber will change how the polarization is altered as it passes through the fiber. In a trans-oceanic fiber the effect could be dramatic; the polarization would likely wander around with quite a high frequency. This would need to be corrected for by periodically sending reference pulses though the fiber so that the receivers could be re-calibrated. Not too difficult, but any inaccessible repeaters would still need to be retrofitted. I also don't know if in-fiber amplifiers are polarization maintaining. They rely on a scattering process that might not be.
Phase-encoding has similar problems. Dispersion, the fact that different frequencies travel at different velocities (this leads to prisms separating white light into rainbows), will distort the pulse shape and shift the modulation envelope with respect to the phase. You either need very low dispersion fibers, and they already need to use the best available, or have some fancy processing at a receiver or repeater. Adding extra phase encoding simply implies that the current encoding method (probably straight-up, on-off encoding) is inefficient. That's not necessarily lack of foresight, that's because dense encoding is probably really hard to do in a dispersive medium like fiber. Again, it's not a trivial drop-in replacement.
The article downplays how hard these problems are. It implies that the engineers simply didn't think it through the first time around, but that's far from the case. A huge amount of money and effort goes into more efficiently encoding information in fiber. There probably is no drop in solution, but very clever design in new repeaters and amplifiers might squeeze some bonus bandwidth into existing cable.
So if this is the future...where's my jet pack?
That is all.
How about using gravity to help the light flow faster? It works for water!
... and therein lies the real issue. You're right, more or less, I certainly wouldn't mind more downstream bandwidth, but I probably wouldn't notice it that much. On the other hand, an increase in upstream bandwidth (even to your 5Mb/s) would be a large improvement in quality of service for me (that's fast enough to stream good quality 720p video).
Not until tomorrow: http://en.wikipedia.org/wiki/Thanksgiving_(Canada)
Well, we'll just have to hope that their competitors will implement the technology
Already have. Actually Alcatel is pretty much playing catchup with all this. Nortel introduced a 40Gb/s dual polarization coherent terminal 4 years ago (despite many people, including Alcatel, saying it wasn't possible). Furthermore Nortel Optical (now Ciena) already has a 100Gb/s version available. Alcatel is pretty late to this game.
Canadian Thanksgiving is tomorrow. I'm not Canadian, but heard about it somewhere recently.
It's Alcatel-Lucent (and not the reverse) btw!
The "fabrication process" is that with uneven glass the glaziers put the thicker bits at the bottom.
Because the speed of flow (creep) is related to diffusion rate a very rough rule of thumb is that if the temperature is above 2/3 of the melting point in degrees Kelvin then it will happen given time and stress.
That's why it shows up in very old and large lead pipes (low melting point) but not in large windows (high melting point).
Polarization in multimode fiber is out because the polarization tends to become random after it is transmitted through a long enough multimode fiber. They are therefore surely talking about single-mode fibers. You can buy polarization maintaining single-mode fiber but it is my understanding it only maintains polarization in one direction. If you had a fiber shaped to allow more than one polarization direction than I believe that by definition this would be multimode (i.e. one mode for each polarization direction, though not nearly as multimode as most multimode fibers) Come to think of it, could you then encode data in linear, elliptical, as well as circular polarization directions?
Anyway my next question would be how do you change the polarization of the light? Do you have a Q-switch laser that can not only turn the laser cavity on and off but can also change its shape to change the polarization of the transmitted light? I would like to see the design of that laser. Of course if you put too much stuff in your resonator cavity then that tends to make it longer which increases your pulse length. Then again they are talking about encoding the phase of the light. Does that mean that they have a very coherent CW laser and then change the phase and or polarity via some nonlinearity on the fiber? Can you do that fast enough to encode useful data?
Just some random thoughts that come up because the article isn't very technically detailed.
maybe we should light up all that mysterious dark fiber we've been hearing about for years.
...
Funny, on the toilet recently I was just thinking about the relative benefits of getting more fiber and squeezing less.
As long as we're bragging... :-)
Here are my results from a few minutes ago: http://www.speedtest.net/result/985839676.png
Fiber to the home (free standing house/single family home, don't know the proper US real estate terminology), at approx $35 per month; that includes IP-telephony monthly charges, calls are extra but cheaper than ordinary land line. Even though I'm paying for 50/50 symmetric, speedtest didn't quite reach that in uplink, I usually see better speeds to a more reasonably located Swedish ISP.
Stefan Axelsson
As long as we're bragging... :-)
But I guess you win in the price-value comparison... €25 is a bargain! I would like in on *that* deal.
Only question I'd have on that link is to how many other places you get your bandwidth. The reason is that I have observed that many of the cheap European and Asian ISPs that provide big connections usually do so as a big WAN. So you get the speed to others on your ISP, and maybe to a couple peer ISPs, but not to other countries. I always test my connection against a server that is not on my ISP, and not in my state. I want to make sure that I'm getting my bandwidth to the Internet at large, not just to a few places.
Of course I pay a good deal more, so I should, but still.
I'm just curious in particular because so many on Slashdot idolize the cheap European connections and in my information research, I've found one of the reasons they can keep their costs down is not having the backhaul to the backbone to support their full data rate. Nothing wrong with that, I think it is a very legit strategy, just something for people to be aware of.
The IEEE standard for 40gbs was finalized a while back. Check 802.3ba. Ratified in June for 40 and 100gbs. They've all been working on this for a while, products are ready to ship today.
Well, as you saw from my result the test server was actually in another country, Denmark to be exact, and quite a few hops away from me (20ms ping time).
But, there's something to be said for your question, certainly. There are two parts to it IMHO, the first is as you say, getting to/from your ISP at all. And the second is getting to/from the US (where many of the interesting endpoints are). In the first case, when it comes to cheap broadband, there is certainly caveat emptor. I could get bandwidth cheaper, but with worse peering, and that's why I chose Bahnhof (Sweden's first ISP, with a heavy dose of anonymity etc. thrown in. They get IP in a way that e.g. Telia-Sonera doesn't; and they're not that bad). Of course, it doesn't hurt that TPB is Swedish and that many Swedes have a nice uplink as well as a nice downlink... :-) (As a matter of fact the strong asymmetry in the US hurts Bittorrent more in my experience than does the overall bandwidth. I upload significantly more to the US than I can get back typically.
When it comes to getting across the pond, we are mostly all in the same boat. There is very little you can do if you're not on a special network (such as the Swedish University Network; SUNET). That's to say, there's less you can do, but not all ISPs are exactly equal. As a small aside, somewhat amusingly, peering/network structure to/from the US (esp. in Scandinavia/Holland etc.) is typically better than to the rest of Europe at large. Getting to a server in Austria can bring tears to your eyes. This has mostly to do with the crap state of network infrastructure in continental Europe in general.
Of course ISPs don't advertise peering agreements/status, so one has to go to e.g. netnod to check that for oneself.
As it happens I'm both on fibre at home and on SUNET at "work", so if you want to arrange a test, I'm game. Just tell me what to up/download to/from where and how, and I'll post (or email) the results. (You can reach me at "middlename" (really my first name) at lastname dot cx if you want to go offline).
Stefan Axelsson
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