Comcast Kicks Tires On 100-Gig Optical Links

Balistyx writes to mention that Comcast has announced the first test of 100-gigabit-per-second optical networking equipment designed to carry data over a production fiber network. The trial equipment will connect Philadelphia and McLean, VA. "In November, Verizon said it completed the first field test of 100-Gbps optical transmission on a live 312-mile network route between Tampa, Fla., and Miami. The telco's test used a live video feed from the FiOS TV network, and optical equipment from Alcatel-Lucent. Comcast's test is different, according to Schanz, for several reasons: It's running live traffic, and the 100-Gbps wavelengths in the Comcast trial are running over the same physical fiber as its existing 40-Gbps wavelengths, which are handled by Cisco Systems gear."

Comments

Keypoints..

[EssJay]

Some interesting keypoints:

• "The 100-Gbps trial connects Comcast facilities in Philadelphia and to McLean, Va., running over the operator's metro and long-haul fiber links. Comcast is using preproduction versions of Nortel Networks' 100-Gbps interface cards, running in the vendor's Optical Multiservice Edge 6500 system"
  
• "It's running live traffic, and the 100-Gbps wavelengths in the Comcast trial are running over the same physical fiber as its existing 40-Gbps wavelengths, which are handled by Cisco Systems gear"
  
• "It's not on some dedicated facility ... It's on [the] production fiber, next to other lambdas."
  
• "Comcast believes it's the first test of 100-Gbps wavelengths with reconfigurable optical add/drop multiplexer (ROADM) photonic components."

What good is it?

[Dan541]

But what good is this 100 gigs if you can only pay for it but not use it?

~Dan

Re:What good is it?

[sahonen]

Hit the nail on the head. I have Comcast's fastest plan in this area and I can only sustain an FTP upload at 50 KB/sec. At 3am. To my own private server. It's ridiculous and unacceptable. If I had ANY alternative I would switch immediately. If having all this extra bandwidth means they can relax their insane throttling I'm all for it as long as they don't try to charge me extra for the privilege. I know for a fact that there's more than enough bandwidth in the pipe. They're just not giving any of it to me.

Re:100 gbps wavelength?

[Beryllium Sphere(tm)]

Backbone fiber uses wavelength division multiplexing, which means that more than one color of light carries data over the fiber. So it's common to talk about lighting up a wavelength ("lighting a lambda"), and in general to use "wavelength" to mean one of the several carrier frequencies on the fiber.

So a "100 Gbps wavelength" means a single laser-receiver pair modulated to carry 100 Gbps.

Re:McLean VA?

[jd]

"Are you thinking what I'm thinking?"
"I think so Brain, but what would the NSA do with ten billion smoked herrings?"

Re:100 gbps wavelength?

[icyisamu]

If you need to see it in action, there is an Emacs command to do that of course, C-x M-c M-comcast.

Re:100 gbps wavelength?

[jonaskoelker]

If you read one of the linked articles, you'll learn that

Unlike other trials that used 10 separate 10 Gbps wavelengths to carry 100 Gbps, the Verizon test utilized a 100 Gbps signal on a single wavelength. Other interesting things from that article:

"This is another critical milestone on our way to ensuring that we have the most advanced telecom network technology at the right time, in the right place, to serve our customers," Having never used Comcast, I'll leave it to those who have to asses the meaning of "serve our customers".

"The field trial also confirms optical networking's role as a critical enabler for competitive transformation, as new services and applications reshape network requirements." I thought peer-to-peer data transfer already "reshaped network requirements" and left the ISPs struggling to keep up.

"Applications based on online video are clearly drivers for higher bandwidth [...]" Again, how about peer-to-peer transfer.

"Transmission at 100 Gbps will enable low latency and significant improvement in real-time transaction. Trading institutions and other Verizon customers using real-time communications will find the associated performance very attractive." I can transfer 100 Gbps by putting hard disks in my backpack and running a short sprint. This is orthogonal to latency (which is what real-time is about). Okay, strawman. Assume the big fiber is deployed, and everybody uses it. Then you'll run into contention issues, and your packet will sit in a queue. I'm not saying bigger pipes won't help, but I want an arguement; right now, all I have is a claim.

Re:100 gbps wavelength?

[patlabor]

Although these dense wavelength division multiplexing systems (DWDM) are using different wavelengths, they are barely different, with lambdas separated by just a few (really almost one) nanometers (10^-9 m). This is possible because looking at the wavelength shows that there is a separation of 100 GHz for 1550 nm systems. DWDM is currently the most efficient (by density) method for transmitting mutiple frequencies of light, and the most resiliant to noise. The wavelengths are always grouped together in center frequency, which is chosen for it's optimal transmission capabilities according to a fiber. The currently popular frequency is 1550 nm, but there were several others in the past. There are even some fibers that are efficient for a few wavelengths, which must be the type of fiber Comcast already laid in this case.