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."

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."

Previous work

[Beryllium Sphere(tm)]

Demo of bonding 10 wavelengths together, each carrying 10 Gbps:
http://gigaom.com/2006/11/14/100gbe/ [gigaom.com]
The comments after that post include one about NTT testing 111 Gbps over a single wavelength for 160 km. That's more like the article, which sounds like it's describing a single wavelength.

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?

[msauve]

McLean is right next to Vienna, center of the MAE East [wikipedia.org] Internet Exchange Point [wikipedia.org].

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.