back to article Verizon boosts 'selected' US backbones to 100G

Verizon has announced that it will be the first service provider to pump "selected segments" of its US long-haul backbone to 100 Gigabit Ethernet speeds, using Juniper Networks routers and Ciena coherent optical-processing gear. "We've already successfully deployed 100G on a portion of our European network, and now we're …

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Pint

Never Underestimate The...

...customer's need for bandwidth.

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10X on Fiber??

I doubt that a fiber with 100G links has 10x more capacity than one with 10G links. A fiber carries multiple channels using DWDM (dense wavelength division multiplexing.) Each link uses a slightly different "color" of light (i.e., a slightly different wavelength.) I single fiber can carry 160 different "colors" when each color is a 10G link. When the links are 100G the "colors" must be separated further, so the fiber cannot carry 160 100G links. I do not know how many 100G links a fiber can carry. I do k now that a fiber carries 80 40G links, so quadrupling the link speed doubles the fiber capacity.

Latency is silly issue. A huge IP packet (1000 bytes, 8000 bits) is transmitted in 8000ns (nanoseconds) at 1G, 800ns at 10 G, and 80ns at 100G. But the speed of light in fiber is 20cm/ns in fiber, so 8000ns is 1600 meters, 800ns is 160 meters, and 80ns is 16 meters. But the link is more than 500 kilometers, so the difference (160 meters -16 meters= 144meters) is inconsequential relative to the speed-of-light latency on the link.

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@another_vulture

The bandwidth cauded by the modulation is still smaller than what the DWDM system typically can do. So I don't think it would be a noticable increase in crosstalk between the channels.

They probably don't even use DWDM at all as it's more expensive than using extra fibers.

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You know what the speed of light is?

Fast enough, thank you.

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10x on Fibre

Yes you can.

The Ciena 100G uses QPSK encoding, with Dual Polarization launch, and a CoFDM technique to pack 100Gb/s of data into the same channel spacing as a conventional 10Gb/s system uses. So yes, you can support 160 DWDM channels of 100G if you like. It is also more robust to PMD than a 10G system, so you can run the 100G system on worse fibre than a 10G system.

Isn't digital signal processing cool.

Simon.

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Anonymous Coward

Ooh! Ooh! I know this one! I know this one!

The speed of light, it's not just a good idea, it's THE LAW!.

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