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2.56 Tb/s Transmission Record
RalfM writes "2.56 terabits of data per second in new transmission record by Bell Labs, Lucent's research arm."
So this thing could transmit my entire mp3 collection in under a half second.
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Tera is a prefix meaning one trillion (10^12), in this case it refers to one trillion bits (not bytes).
What?
Tera-BITS per second. So that would be 320 Gigabytes per second, so half would be 160 Gigabytes of MP3's.
For fun, look up bit and byte in the dictionary. They're not actually the same thing.
No, 'cause the LambdaXtreme unit used is unbelievably expensive, and you need at least 2 of them.
Also, you need EBDA single-mode fiber, which isn't the majority in the ground.
Soon, though.
Charles E. Hill
Core Network Engineer
Lucent Worldwide Services
Learning HOW to think is more important than learning WHAT to think.
Wrong. don't confuse LATENCY and THROUGHPUT.
While often latency (ping) gets lower with bandwitdh increase its often not the case. Try to play Quake on 1Mbit satellite uplink and you would go back to 56k modem after first round.
Actually, the article said they used raman amplification, not Erbium Doped Fiber Amplifiers. Raman can be used in either the C-band (1530 to 1565nm - typically where EDFAs are used), or the L-band (1565 - 1625nm). Actually, I think Raman can be used at any point in the spectrum, but don't quote me on that because I am not a physicist!
EDFAs do allow signals to travel long distances, but the problem is that they are "single point" amplifiers. The signal gets attenuated down quite a bit after traveling 50 miles or so and then is boosted back up by the EDFA. The signal to noise ratio has already dropped too low and can't be recovered. So with EDFAs you are limited to a relatively small number of hops (six or so) before it has to be electrically regenerated (detect the signal and then electrically send it to a laser to be retransmitted cleanly).
Raman amplifiers use an effect called Stimulated Raman Scattering that uses the fiber in the ground as the amplifier itself. By using a pump laser transmitted into the fiber (typically opposite to the direction of data flow), the power of the pump laser's low wavelength is transferred in the glass to the higher wavelengths of the data signals. Amplification is then distributed along that 50 miles of fiber or so between pump lasers. The signal power never gets as low with Raman as with EDFAs, so the signal to noise ratio is kept higher. That's how they are able to get much longer distances between electrical regeneration out of these new systems.
I don't know much about SOAs, but I've heard they are not good for multichannel systems. Something about the fact that they are noisy? I think they are good for single channel applications.
This research is great and all, but telecom providers are having enough trouble selling capacity on their existing EDFA systems. Something is going to have to drive a lot of demand for bandwidth before systems like this one from Lucent get deployed.
Ping times (for small ping sizes) are approximately equal to the amount of time it takes for light to pass through the fiber and back. Most people in telecom use 1ms per 100 route miles of fiber as a rule of thumb. (remember the fiber does not follow a straight line between cities!) So if it is 4200 route miles between NY and LA, your ping will take 42 ms to get there and 42 ms to get back = 84 ms.
You can't change this basic fact of physics. If you were running somehow on a microwave system instead of fiber, you would actually approach the speed of light in free space, so your ping time would be a little faster.
By the way, there are other factors that go into the delay of your ping besides propagation delay. Other things such as: congested buffers in routers along the way, serialization delay to clock the packet out of your device (negligible on fast links, but a big effect on dial-up), the response time of the remote device, devices delaying packets to do an ethernet arp, etc... Propagation delay usually ends to be the biggest factor when you are talking about ping times.
Following this
page (google cached) the boeing 747 can take (full of fuel) about 200000kg at max distance 13000 km and at speed of 910 km/h
I estime the DVD-ROM weight to 20g, and use the 17.1GB ones (=136.8Gb)
so "data capacity of 747" is 200000
the time of the fly in the worst case is about 13000/910*3600 ~= 51000 seconds.
let's divide 1.4Eb / 51000 ~= 27Tb/s
So ower beloved 747 has only 10 times bigger data transfer capacity, but the Bell Labs solution must be much more than 10 times cheeper
(And we have not discused the latency yet