Verizon expects better economics, lower latency with U.S. 100 G deployment

Verizon expects 100 Gb/s connectivity, which it plans to deploy on certain IP backbone routes in the U.S. by the end of June, to reduce costs and make its IP network operate more efficiently.

Previously the company would have had to use as many as 15 individual 10 Gb/s connections to achieve the same throughput, Verizon Director of Optical Transport Glenn Wellbrock said in an interview. “It depends how you hash those flows. The throughput is better because you’re not breaking the [traffic] up. You can trunk a larger amount of user traffic and manage it more easily. You have one trunk to manage instead of 10.”

The equipment supporting Verizon’s 100 Gb/s deployment includes Ciena optical transmission systems and Juniper routers. Those are the same vendors that supported Verizon’s previous 100 Gb/s deployments on certain European routes.

Lower latency
Verizon expects to see lower latency using the 100 Gb/s network. The reason, Wellbrock said, is that the optical transmission equipment underlying the deployment uses a coherent receiver with digital signal processing that eliminates the need for dispersion compensation.

The high-speed optical transmission equipment that carriers have been using for years has included about 15% of additional fiber at each repeater point, Wellbrock explained. Those repeater points are positioned about every 50 miles along each network route. The extra fiber length is there to compensate for variations among transmission speeds for different wavelengths, but the downside is that this process increases latency because it increases the distance that the signal must travel. By using digital signal processing at the opposite end of the route to address dispersion compensation, the coherent receiver eliminates the need for the extra fiber at the intermediate repeater points, thereby minimizing latency, Wellbrock said.

Carriers have been increasingly interested in reducing network latency since financial companies have become increasingly interested in high-speed algorithmic trading where every millisecond matters.

The optical equipment that Verizon is using conforms to ITU and IEEE standards, Wellbrock said. For the long-haul portion, a 100 Gb/s signal can be carried on a single wavelength. Within an individual central office, four individual 25 Gb/s wavelengths are used.

The routes that Verizon initially is upgrading include Chicago to New York, Sacramento to Los Angeles and Minneapolis to Kansas City. The company plans to upgrade additional U.S. routes this year.

“In North America, Verizon is ahead of the pack,” said Tom Mock, senior vice president of corporate marketing and communications for Ciena. “But we’re starting to see [100 Gb/s deployments] happen broadly around the world. It’s happening faster than some anticipated because the economics are working out.”