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Good News From The High-Speed Networking Front
Degrees writes "Over at Small Times there is an article about two Danish companies that want to make deploying fiber optic lines easier with MEMS-based packaging technology. (MEMS is Micro-Electro-Mechanical Systems - described here). Also mentioned is that the big three U.S. telcos are working on fiber to the home plans." And punkmac points to this eWeek article which begins "An Intel Corp. backed startup, SolarFlare Communications Inc. said Monday that it has developed a working prototype of a chip that will permit 10G-bps communications over standard CAT5e copper wiring. SolarFlare's chip will be used as evidence that 10G-bit over copper can be done, in anticipation of a draft IEEE standard to be developed later this year."
will boost the communications businness heaps on 2004 since with no big investment we get a performance upgrade. Way to go folks. and the rest of our should pay attention to the stock market.
"The quality of life is inversely proportional to the number of keys on your keyring."
Getting ?fiber to the home? ? telecom?s long-sought solution to the problem of directly delivering high-quality and high-speed video may cause some more problems. Alright, this would be able to bring high bandwidth lines to homes, but how about backbones? The current technologies are still pretty much limited at 40Gb/s for one single fiber. And since all-optical networks are still developing, I believe it may still be a while before we can profit from this.
DrkBr
The EETimes carried this same story with more technical details and a few criticisms as a cover story in the week's paper edition. It's also available online here at the EEtimes website.
You must be doing it wrong then. My cable modem disconnected for hours several times per week, usually on Fridays when a technician couldn't be dispatched until Monday or Tuesday. They (Charter) sent out several guys to try to fix it, and always made excuses that it was our fault/problem (plus tried to bill us for the trip to boot, even though we weren't getting what we paid for). We switched to DSL, and SBC made NO excuses. They simply provided us with a rock solid, reliable connection that hasn't gone down once in the 11 months we've had it. The day I go back to a cable modem is the day dialup is the only alternative (but at least dialup is more reliable albeit painfully slow).
"The current technologies are still pretty much limited at 40Gb/s for one single fiber."
That's true, so then you deploy DWDM (dense wavelength division multiplexing) to multiplex 50 or 100 (or more) wavelengths of light, each carrying 10 or 40 Gb/s in traffic.
Add to that all the dark (unused) fiber deployed in long haul terrestrial networks in the U.S. and we have a lot of backbone fiber capacity. Typical fiber counts on the long-haul cables deployed in the late 1990s were 144 to 288 fibers or more.
Al Bonnyman
Community Broadband Networks
10Gbps over copper was done, over limited distances, by Nortel three years ago. It's not new. In fact they are working with 40Gbps now, though not over copper, yet.
The technology ofr literally blistering speed is already available and hass been for some time. Additionally, it is not that expessive, relatively speaking, to offer speed that are significantly higher than todays broadband offerings. But, people keep bringing up the fibre to the home story and this is where the whole thing falls apart.
While new developments may indeed get fibre to the home but, no provider is going to "rewire". If they already have copper in the ground they are not going to upgrade. Why? Because of the cost.
Providers are already getting top dollar providing anything from 128Kbps (sometimes less) to 2Mbps. There is no incentive for them to make the massive capital outlay needed to bury fibre on routes that are already served by copper. It is unlikely that their customers will pay $100 per month versus the $50 that the providers already get for broadband so, there is no real demand to motivate the providers. Even new services like video on demand work adequately well over copper to negate the need for revamping the infrastructure.
No, providers will continue to offer the same services over their copper infrastructure and when things become saturated they will start to penalize people that use it the most. This is already happening with Comcast and AT&T.
Check out this eetimes article for a little more detail than the article in eWeek:
http://www.eetimes.com/showArticle.jhtml?article ID=18401022
Understandably, the companies that manufacture the cable aren't enthusiastic about SolarFlare's technology, as they would prefer that everyone rewire with Cat6 or better to do 10Gig. They claim that SolarFlare is "overclocking" the cable (my own words), and that some installed Cat5 will work at 10 Gig and some won't. Cat5 is tested to 100 MHz; SolarFlare claims they can do 10G with 350 to 400 MHz of bandwidth and that Cat5 really supports this bandwidth. The cable manufacturers just need to test their Cat5 to this higher frequency.
320mbps on wireless UWB
Remeber that Network lines (CAT) are in paris of 4. So the speed of 10gbs is over 4 cables 2.5gbs each. I know that RG6 operates at 2200 MgHz. We have a room to grow from Cat5e (350 MgHz).
Well' get there - Looking forward to Cat6 and Cat7. Here is the current rating for network lines:
CAT-3 = Category 3, 3 pair 24 ga. solid wire - up to 16Mhz (No twist)
CAT-5 = Category 5, 4 pair 24 ga. solid wire - up to 200Mbps. (avg. 13 twists per foot)
CAT-5e = Enhanced Category 5, 4 pair 24 ga. solid wire - up to 350Mbps
CAT-6 = Category 6, 4 pair 24 ga. solid wire - up to 550Mpbs
CAT-6e = Enhanced Category 6, 4 pair 24 ga. solid wire - up to 1000Mbps
CAT-7 = Category 7, 4 pair 24 ga solid wire - up to 2.4Gbps
Soon as we develop a shielded style RG6 in pairs of 4 the 10Gbs would be achievable. Copper is limited by our switching technology - the major factor with Optical and Copper is the length of drops. You can run optical a greater distance.
Anyone know what the theoretical speed limit of copper cable is? 10Gbs seems faster than copper can go to me.
Depends on its length, thickness, surrounding dilectric, shieling/balance/discontinuities, and the speed of the carrier/modulation. (For any given design of wire it's mainly the length.)
Copper, not being a superconductor, has resistance. The resistance combines with the stray capacatance between the conductors to form a distributed RC low-pass filter/delay line, which attenuates and delays higher frequencies more than lower frequencies - progressively more as the wire gets longer.
It gets even worse for REALLY high frequencies, because they create eddy currents in the copper that impede the penetration of current into the conductor, restricting the current to the outer part of the conductor (the "skin effect") and thus raising the effective resistance and exaggerating the frequency-selective attenuation.
This selective attenuation and delay weakens the signal - more at high frequencies than at low. As the wire gets longer the signal gets weaker and competing noise pickup gets stronger, reducing the signal-to-noise ratio and thus the amount of signal that can be carried.
But the selective attenuation and delay also distorts the waveform, creating "intersymbol interference" (stored charge from previous bits affecting the latest bit). This can be compensated for.
Current technology using SERDESes (fast serial bit streams), with some compensation for the selective attenuation (both preemphasis at the transmitter and compensation at the receiver), can get 3 Gbps through about a yard of printed circuit, or several yards of wire. More advanced devices (using tricks like four-level encoding to get two bits per modulation perios and feedback from the receiver to the transmitter by a return path) can go faster and a bit farther. (A transciever using all four pair of a Cat-5e, as of last year, could get gigabit ethernet across 30 meters.)
Frequency-domain techniques (like ADSL) can do still better. And coding schemes have been developed that get within 50% (turbo codes) or even 90%+ of the Shannon limit bit rate.
But what IS the shannon limit bit rate: It depends on a LOT of things. The biggest are:
- Length of the wire.
- Thickness of the wire.
- Quality of the dilectric around the wire.
- Interference coupled into the wire (i.e. how many other wires are in that bundle, what signals they're carrying, {for twisted pair} how tight the twists are and how they vary from conductor to conductor), how hot the wire is, etc.
You should be able to get gigabit rates to a box on your block with copper pair, with a small router there and fiber to the rest of the net. (This is "fiber to the curb".) For 10G or beyond you'll probably need CO-AX (ala cable TV) or fiber from the curb box as well - otherwise the curb boxes would need to be so close together that they get too costly - and you might as well have strung fiber from the one-per-neighborhood boxes.
(Maybe they'll push it a little farther. But I wouldn't hold my breath. Remeber that, in the US at least, you've typically got Cat-3 to the "curb" box which serves no more than 100 homes. If you're going to spring the bux dig it up and string 5e or 6 you might as well string some fiber. Later that can easily be upgraded to Tbits and beyond by transciever changes at the ends.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Okay, let me nit-pick the example on your otherwise correct statement..
> even if we're streaming HD video to or from the downstairs entertainment center
I'm currently streaming HD video from my entertainment center to/from my 450MHz G4 Cube using 100Mb Ethernet and el-cheapo $30 switches.
Broadcast HD video is an approximately 20Mbps MPEG2 stream. So, it is not a burden on even modest hardware. Other HD formats, like cable, satellite, and HD-DVD might be a bit faster in the future - like maybe 40Mbps. But, it won't go much beyond that.
The other option would be streaming uncompressed HD video (what would that be.. 1920(x) * 1080(y) * 32 (bpp) * 60 (fps) = 2.9Gbps for 1080p ). That's excessive even in a 10Gbps network, and it's unnecessary because all forms of HD will be transferred in a compressed format.
The other factor is whether our benevolent entertainment overlords will ALLOW us to xfer HD content around the house.. The broadcast flag, and all the security/crypto standards used for cable, satellite, and HD-DVD will stifle many of these really obvious uses of future home networks.