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Fiberless Optical Networks
Alien54 writes "According to this Forbes Magazine article, the time for Fiberless Optical Networks may have arrived. Wireless optics have been given up for dead until very recently. But now better technology and lower product costs have enabled some to solve most of the problems. AirFiber (a company mentioned in the article above) is emerging as one of the favorites in wireless optics, and seems to have a set of good answers for the inevitable "bird and fog" questions: Can a flock of birds take down a network by flying through the lasers? Can a heavy fog send your precious information into the ether?"
Hi, just want to tell you that this laser thing really is old. Here at Aachen (in the very western part of Germany) the student hostels "Die Türme" (the towers, called so for being the four heightest buildings here in Aachen) of the technical university RWTH use such a laser to connect their local network via the laser with the main computer facililty of the RWTH and the web. The laser is about 4 years old and has a max. bandwith of 40Mbit. And yes, fog and heavy rain is a problem. Have a look at: http://www.oph.rwth-aachen.de/ag/netzwerk/technik/ laser.html
for the technical data and here, you'll get a picture: http://www.oph.rwth-aachen.de/ag/netzwerk/technik/ laser.bilder.html
(No, that's not me on the picture)
. Sorry, all pages are in german.
Actually, the article and the summary above call it Wireless Optics, not Wireless Fiber. It uses Optical technology without using Fiber Optics. It uses lasers.
The rest is the attack of the marketroids, I suppose
"It is a greater offense to steal men's labor, than their clothes"
So while you're sitting there telling us that it's all vapor and research, while companies around the world are currently using AirFiber technology to provide internet service.
Links you might want to look into...
h ttp://www.alphalink.com.au/~derekw/upntc vr.htmt s/laserlink.html/ members.mint.net/n1bug/tech/laser/lase rfr.htmle pairfaq.org/sam/lasersam.htm ://www.qsl.net/k3pgp/opening.htm
http://atrey.karlin.mff.cuni.cz/~clock/r0nj4/
http://www.hut.fi/Misc/Electronics/circui
http://www.geociti es.com/SiliconValley/Lakes/7156/laser.htm
http:/
http://opencollector.org/
http://www.r
http
The first link actually seems to be the best - instead of lasers, ultra-high brightness LED's are used - no great distances here, but aiming doesn't have to be as accurate, fog/rain/birds are less of a problem, the hardware interface is rather simple, and the LED's (and other parts) are cheap!
I support the EFF - do you?
Reason is the Path to God - Anon
"Most likely, yes. Anything that interrupts or degrades the signal will be a problem. What about thunderstorms, which tend to emit on a lot of frequencies?"
I don't know much about the other companies, but I know with AirFiber:
* Birds are not an issue; signals are rerouted (the network is redundant) as soon as the connection is broken, which then automatically relinks;
* Fog hasn't been a problem. Look at it this way -- if you can see a flashlight shining through the fog, you can see this laser.
* How would thunderstorms be a problem? We're not talking about RF frequenciese here!
Thing I'm wondering is what is the maximum available bandwith with an unladen african swallow, hmm?
by ramping up the power but people might complain when we run out of birds.
Also it could get messy for a while what with all the headless pigeons and arms of careless windowcleaners falling about the place.
Bob.
Not the birds or the fog. But if this is takn up by a lot of ppl/companies, will we not see bandwidth pollution similar to what is/happening with devices that operate in the 3G spectrum? The portable (not mobile) phones, the radio lan cards that are made, the airport (from apple)(yeah bastratdised radio lan cards), [perhaps the previous could be summed up as 802.11].??
What you are thinking of is the RF (radio) spectrum. Since it is broadcast, it is regulated, and yes it is being used up.
This, however is a point to point laser beam... (as in light... a totally different part of the EM spectrum) the only other station receiving the beam is where it is pointed.
I work for a major Internet bandwidth carrier and know how long it takes to get fiber/DS1s/DS3s provisioned both in and out of the US -- for freeking ever. Totally unacceptable times for the fast moving business of technology that we all work in. DS3 in a month is a total miracle. DS1s get installed after about 6-9 weeks on average. Our customers get really impatient, and there is nothing that we can do because we rely on the Local Exchange Carriers to get the line to the customers. Getting the customers to the core is not an easy job.
2 00&cid=5 because I thought it was just plan funny, even for a troll post.
Having the ability to point a laser at some building across town, having been able to set it up in three days or less, would be flippin' awesome. Think about how great this would be for one time conferences and setting up temporary solutions. Who cares if it is not totally stable -- birds, fog, and your occasional script-kid gone cute with a big kite, trying to knock out your service.
The building at which I work does in fact have a wireless (not optical) Sonet connection, along with standard OC12s and OC48. It should be noted that the city which I work and live also is a current test bed for Sprint and their wireless broad band solutions (also not optical in nature). These are excellent and very viable solutions for a quick connection.
It should be noted that I had moderator points and *really* wanted to moderate up http://slashdot.org/comments.pl?sid=00/08/20/2234
People may use wireless optical stuff to simply avoid dealing with awful phone companies. Our t1 is upheld by the Verizon fiasco (may be in Fri) now. Att *could* do frame relay for us, as it is 2k for the drop and 1900 a month, in 30 to 45 business days. To expedite the delivery to 15 days, they want to bump us up to national service, so that would be 7k for the drop, and 5300 a month on a 36 month term = a 200k over 3 yr. commitment. We are actively looking at the lucent wireless gear, but building height on our new site is a problem.
Its misery like this that will help push people to find new high bandwidth solutions.
matt
const double MAX_POWER=500.0*ONE_MEGAWATT
const double NORMAL_POWER=500.0*ONE_MILLIWATT
if (flockOfBirdsDetected()) {
setLaserOutputPower( MAX_POWER);
wait(1);
collectCookedDinner();
setLaserOutputPower( NORMAL_POWER);
}
Donte Alistair Anderson Roberts - hi son!
Karma: Chameleon
Can a flock of birds take down a network by flying through the lasers?
;)
Well, if you increase the power of the lasers, you could then only need to pose this question:
Can a network take down a flock of birds flying through the lasers?
Problem solved.
With the recent Lucent record of over 3 Tbs transfer speed across 300 km using "classic" fiber optics channels (reported on slashdot earlier) I see less utility value in pursing wireless fiber optics channels. The decreased material costs of fiber will be more then likely offset by increased costs in power consumption, due to attenuation of the signal in water molecules and solid particles. I think wireless fiber still has more than a few years to mature.
Firing lasers off through the sky is only a temporary solution. You will always get higher transfer rates using an actual fiber becuase it is such a better transmission medium. However, it is quite expensive to run fiber all over the place right now, as prices go down it will become more feasible and things like this will die off.
780 nme t.HTM
http://www.airfiber.com/products/faq/Html/helps
As for saftey if meets IEC Class 1 requirments.
The FAQ seems very comprehensive.
Wireless networks have several advantages over traditional land lines, especially in areas of rapid expansion. For one, the right of way issues are greatly reduced. It is a severe pain in the ass just filling out the forms to try to drag a cable across town, or across the state, or across several states. And it's not cheap either. The expense of actually laying the cable is also quite substantial. However, with wireless networks, you only need to setup a few base stations and boom, you've got a network.
Pretty soon, everyone and their mother (literally!) will be wanting / needing broadband access, and right now a lot of people (and businesses!) just don't live where it's possible to get broadband any time soon. DSL is great, but the limited range means a lot of people are left out, and the limited speeds makes it unsuitable for a lot of uses. The best hope for most locations is a cable modem or getting their own line laid, cable connections are not particularly suited for high bandwidth serving or businesses, and paying for your own line to be laid is just murderous. On the other hand, if someone could just install a wireless connection with T1 -> OC1 (or faster) speeds with little delay they would make a lot of people very happy.
Additionally, wireless networks are well suited to developing countries. There are lots of places on this Earth that lack even basic telephone service. By bringing wireless networks to these places, they can not only get phone service at much less the cost than they would be able to through more traditional setups, but they can actually get not too shabby connections to the wonderful world wide internet. In fact, many countries are deploying wireless telephone networks for precisely these reasons.
Well, look at it this way. Think about how long it takes to run a 30 mile fiber line.
True, that does suck, and it's still pretty expensive.
Now, think about how long it would take to run it wireless. Just point and shoot.
Easier said than done. You'd need to calibrate the transmitting device to probably the nearest thousandth of a degree in each direction to be able to hit your receiver about, say, 1 mile away. (very crude, out-of-my-arse calculations.)
The other issue is what might be in the way of the signal -- around Pittsburgh, for example, the terrain is rather hilly. It'd be hard to set up a link between downtown (even on top of the USX tower, ~850 feet high) and Greentree, only a mile or so away, as Mount Washington tends to get in the way. Not to mention what random building might pop up in between your two stations.
Bringing something like cable or DSL into new areas would be quicker and cheaper. The labor costs for laying the line is much higher then a more expensive wireless system.
True, in maybe the Midwest where there are no tall hills. Around here, we're stuck with the classic guided media, expensive as it might be.
DrQu+xum: Proof that the lameness filter doesn't work.
From the article:
"And, with asynchronous transfer mode technology (ATM), the lasers have become intelligent enough to track the laser beams between the two optical transceivers, so they never get off target."
How the heck is ATM going to keep the lasers on target? I think the author confused this with ATM signallig setting up SVC's on the fly to provide reliable data transfer through the network in the case of a link going down.
Bit rate is proportional to bandwidth times the logarithm of the signal-to-noise ratio. To maximize bandwidth, you go up to higher and higher transmission frequencies. To maximize signal to noise ratio, you step up the transmission power. But in a wireless laser network, both of these steps have their disadvantages.
The first problem is essentially that the higher frequencies (e.g. infrared, which is on the order of microns, as opposed to microwave, which is on the order of centimeters) are more susceptible to various scattering phenomena. The most frequently mentioned is, of course, fog, dust, smog, etc. These scatterers are far to small to have any significant effect on, for example, cellular communications (transmitted signal has a wavelength of tens of centimeters, not microns), but they are excellent scatterers in smaller wavelengths. In addition, the atmosphere itself scatters visible light more and more effectively as you go to higher and higher frequencies, reaching a maximum somewhere in the ultraviolet. This is due to the electronic properties of diatomic nitrogen and oxygen and cannot be avoided. (As a side note, it is also why the sky is blue and sunsets are red). So, one cannot step around the fog problem by going to even higher frequencies. I believe, but am not certain, that fiberless lasers still operate in the IR.
The second problem, of course, is that stepping up the power output of the transmitter is expensive. A tenfold increase in bandwidth requires a thousandfold increase in signal to noise ratio. To see why this is so, imagine that with a given signal to noise ratio, you can resolve 16 signal strengths with a bit error rate of less than, say, 10^-8. This means that you can transmit 4 bits of information per symbol. To get twice as many bits per symbol, or double the bit rate, you need to be able to resolve 256 signal strengths - i.e. square your signal to noise ratio. To get 12 (three times as many) bits per symbol, you need to cube your S/N, and so on. Essentially, you have to double your S/N for each additional bit per symbol you wish to be able to resolve at a certain bit error rate. Hence the need for enormously increased power to achieve relatively modest increases in bandwidth.
So, with these constraints in mind, it will be interesting to see what optimum is achieved by TeraBeam et al, and how resilient their systems turn out to be.
Dave Bailey
Ibag
"Me fail english? That's unpossible!" --Ralph
This reminds me of something more than 20 years back: Datapoint's "ArcLight", for their Arcnet.
Arcnet was a token-ring based network with a broadcast topology. Cut the connection between two parts and it immediately reconfigures into two nets. Plug it back in and it reconfigures into a single net.
Ran on 8080-based terminals.
To get between buildings they used a gadget with an infrared laser diode (which had just come out) and a photodiode - each behind a lens about 6 inches in diameter. The device looked somewat like a weatherproof half-height-full-width monitor case with a little bit of a lightshade and the screen replaced by a couple of big glass eyes.
In a city where most buildings weren't skyscrapers (so a little defocussing could deal with building sway and clear-air turbulence without too much energy loss and interference acceptance), clouds and fog were rare, and at a time when high-speed data lines were 300 baud, it was great. A LAN that spanned multiple buildings. If the fog rolled in the network partitioned until it went away (no data between the head office and the branch for a couple hours, but the nets WITHIN the buildings were still up. Birds were handled by retransmissions that were part of the normal protocol.
Something similar would be easy with IP these days: Run a low speed (56k, T1, whatever) between the buildings AND put up the high-speed link. On foggy days your bandwidth drops but your connection is still there. IP also understands flakey connections and rerouting around them, and TCP understands using retransmission to make a reliable connection over unreliable links.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
It's amazing. Take a perfectly normal concept, like meshed networks, and apply it to wireless, and suddenly, you have made some kind of great advancement of science.
I don't see how this is any different than normal problems. Ther are using a wireless PHI.. fine.
The only point the article has made is that the price of optical open-air laser networking gear has come way down, so now it is feasible to build meshed networks with it, and hence, overcome some of the inherent problems with it.
And if the equipment used to cost $150,000.. how much do you think the monthly rental for that DS3 cost anyway? Not cheap. It will quickly dwarf the cost of equipment.
Of course, when we talk about canned networks for corporations (which *IS* a big deal these days), this gets more interesting.
Can a flock of birds take down a network by flying through the lasers?
Maybe they could adapt RFC 1149 - A Standard for the Transmission of IP Datagrams on Avian Carriers and, instead of seeing the birds as a potential problem, use them as carriers. Sure, a device would have to print the scrolls of paper, and attach it to the birds. It would probably decrease bandwidth, as the mentioned RFC mentions: "Avian carriers can provide high delay, low throughput, and low altitude service.". It's worth a good read.
To deal with this, they could also use RFC 2549 - IP over Avian Carriers with Quality of Service .
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Roses are #FF0000, Violets are #0000FF, find / -name '*base*' |xargs chown -R us && mv zig greatjustice
Then for example you could connect to your linux server from your basement 100 stories underground when nuclear warheads are going off above you.
Two small problems with that:
1. Your Linux server had better be in a reinforced building strong enough to withstand a nuclear blast.
2. Even if it was in such a building, the radiation from the nuclear blast would interfere with the wireless communication.
In the interests of keeping this post on-topic, this is different from wireless/packet radio in that light and radio waves are two very different things. Light waves are on a *much* higher frequency, and as such aren't as prone to interference from man-made radiation (such as the nuclear blasts that sips brought up). But, the tradeoff is of course that there are line-of-sight issues.
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I pledge allegiance to the flag...
of the Corporate States of America...
Hrm. Lasers are inherently polarised. How easy is it to switch that polarisation and to transmit (say) error correction in the polarisation, information in the carrier?
Beware to the people that are interested in optical networking, unless you are so interested purely from a research standpoint.
Optical Networking is the term to be talking if you are a Venture Capitalist these days. VCs are just pumping more and more money into any company that has optical networking in its business description. And, just as dot-coms had their flops, so will optical networking.
Optical Networking stocks are also flying through the roof, just as dot-coms did a year or two ago.
I'll be wary of optical networking for a good while until several leaders truly come out ahead of the pack.
You should never take life too seriously - You'll never get out of it alive.
Has anybody thought about the security issues?
One of the advantadges to fiber is that it is incredibly difficult to tap, and the tap can be easily detected. Is the same true of wireless optical? And is tapping even relevant? I would assume that in the case of the Internet, you've got Carnivore tapping you, but otherwise fiber lines can pretty much be assumed secure. In the case of private networks, anyone with the budget for wireless optical could probably come up with a good encryption scheme. But is there anything I've missed here in the tapping issue?
The purchasers of bandwidth understand:
- "Fiber" to mean very fast data sent via light (in something called "fibers" or "fiber optics" or something like that...)
- "Wireless" to mean signals sent between two stations without any hardware spanning the distance. (Just install a box at each end and maybe an antennaish thing on the roof.)
So "wireless fiber" produces the idea of sending high-speed data via light between two sites with gadgets on the roof without anything but open space in between them.
Even if the words don't really make sense when you look at them closely.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
25 years ago, the carrier I was on had a big honking radar. We used to hear scuttlebutt that the techs would get seagulls off the mast by mircowaving them. We figured it explained mystery meat and scab steak.
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Infuriate left and right
I took his remark to mean that if there are lots and lots of R2-D2s around, instead of direct long distance links, you would reroute thru closer neighbors.
Sort of like if long distance phone calls are out, you call Aunt Martha who calls cousin Bob and so on, each being a bit closer, until the final local call goes thru.
I did something similar once, when home to work was not a local flat rate call. A friend in between, who was a local call to each place, installed an extra phone and set it up to call forward.
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Infuriate left and right
Well it needs to be directional enough, so lasers will do. IR will penetrate fog and smoke alot easier than visual light as it is. Fire Fighters in big cities now have an IR camera they can take in with them into rooms pitch black with oily smoke, and they can search out victims and survivors just fine thank you. So IR is a distinct advantadge when it comes to smoke and fog.
"It is a greater offense to steal men's labor, than their clothes"
"With new eFog, your point-to-point wireless optical data communications link can be enhanced into a local area network!"
Next quarter, analysts forecast the public release of eClouds which will allow for a wide area network with a range of approximately 7 miles.
Kevin Fox
Kevin Fox
OK, I must just be dumb or out of it, or something along that line. But, why do they call it wireless fiber? It doesn't make sense, a fiber is a solid object, a "wire" if you will. Wireless would imply that the "wire" does not exist. Why not just come up with a fun buzzword that actually makes sense?!?
Most of Dave's comments are relevant to RF communication, not to optical.
Capacity is proportional to the logarithm of (1+signal to noise ratio). A small but significant difference. The result is that for a given power budget it is always better to use as much bandwidth as possible unless you are limited by arbitrary constraints such as the FCC's dumb frequency management practices.
There's no need to go to higher optical frequencies to increase capacity. The carrier frequency of a 1.3 micron infrared laser is 230 terahertz. It's easy to see that a few hundreds of megabits per seconds barely scratch the theoretical capacity.
You've got so much bandwidth in optical that more than one bit per symbol makes absolutely no sense. In fact, you want LESS than one information bit per symbol by using forward error correction codes.
The right frequency to choose is in the atmospheric window wavelengths - those least absorbed by water vapor.
In fog conditions the cumulative attenuation per meter is so high that even a hundredfold increase in laser power will not make a significant increase in the effective range. You are stuck with a few hundreds of meters. Deal with it. AirFiber's architecture looks like the right way to do it. Even if you ignore the bird problem, with a relay every few hundreds of meters the end-to-end reliability drops exponentially with the number of hops the signal has to go through. A mesh architecture can cover long distances while still maintaining adequate availability.
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Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
This wavelength is around the peak of the first Atmospheric window. It's also cheap because it's the wavelength used by CD readers.
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Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.