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Nortel gets 6.4 Terabits on a Single Fibre
GFD writes " Nortel claims to be able to do 80 gbits/sec in a single wavelength. Using their current top of the line DWDM equipment which handles 80 wavelengths on a single fibre they get 6.4 terabits per second.
What's scary about this is that future DWDM products are claimed to aim for 400 wavelengths per fibre. That fibre would be able to carry over 21 million T1 channels! "
Would we have then reached the final/ultimate speed limit?
Before that happens, we need to concentrate on our algorythems and develop better compression. Sure people are getting rid of compression just cause there is mode bandwith.
You're doing the same thing that a lot of the general populace does, and getting latency mixed up with bandwidth.
Latency is how long it takes for an individual packet of data to get from one place to another.
Bandwidth is the total amount of data you can get from one place to another.
A little comparison: if you had a large plane that had a top flight speed of about 300 mph (mach 0.4) and could carry 1000 passengers and you also had a jet fighter that could travel at just over mach 4 (3000 mph) and transport a single passenger. Most people would agree that the jet fighter was "faster" in a very real sense than the large plane (by a factor of 10). However, with two cities 1000 miles apart, (ignoring time spent loading, unloading, refueling, etc.) the large plane could transport 2000 passengers in 10 hours (3.3 hours per one-way trip) while the jet fighter could transport 15 passengers. With vehicles, carrying capacity (bandwidth) and speed (low latency) don't get confused. Yet, somehow, when you replace planes with modems, the average consumer gets confused and thinks that speed means something completely different than it means in any other context. Speed is how long it takes to get from here to there (miles per hour, for instance).
Very luckily, however, for big expensive products that aren't aimed at the average consumer, latency is considered very important.
When you compress data that is being sent live, you actually have to slow things down in order to do it. (look above at explanation of what speed means, if you're unclear already) This is because you can't effectively compress a single bit or a single byte, so in order to compress you'd hold onto the data for a little bit before sending it off.
With your average consumer modem, compression slows things down by 15ms or however long it takes to receive a large enough block to send from the user (whichever happens first). With a normal home modem, though, you've already got something like 100ms that's wasted going across that link, so in most instances another 15ms isn't much, and is a good tradeoff for the slight boost in bandwidth.
When you've got a DSL line, however, you've got much lower latency than a normal modem would get, so something like 15ms tacked onto it would be doubling your latency. Double (or worse) latency in exchange for a small increase in bandwidth simply isn't worth it. It would just slow down your overall experience. (The only thing where you might want high bandwidth more than low latency is, basically, if you're downloading a lot of large files (like porn or software), and those are usually already compressed (JPEG, GNU zip, ZIP, etc.))
Improving switching and routing speed is much more important and useful. Adding compression to high-speed lines is a bad idea.
Also, electrical impulses already travel at about 2/3rds the speed of light -- outside of your CPU the speed of light over the speed of electric impulses isn't too much of an issue...