Off the Rack: Cox Switches Save Space

Cox Communications' San Diego system replaced eight seven-foot racks of networking equipment with two high-density optical switches to connect its two primary data centers for telephone traffic.

The upgrade not only saved space but cut power consumption, said David Vaughn, telephony engineering manager for Cox San Diego. “It saved us a lot of rack space, a ton of power and a ton of complexity from running copper cable everywhere,” he said.


Vaughn said installing Ciena's CoreDirector optical switches required running only a handful of fiber-optic jumpers within each of the two data centers instead of a three-foot-thick bundle of copper cables with its previous synchronous optical networking (SONET) equipment. “You could barely reach around the bundle,” he said.

Cox San Diego was the first cable system to deploy CoreDirector, said Ciena senior director of service-provider solutions Mitch Auster, who added that another multiple-system operator, which he wouldn't name, is deploying the switch.

“We're starting to see the backbones of telco and cable networks becoming very similar,” he said.

Other Cox systems are evaluating CoreDirector, including those in Phoenix and Atlanta.

The Ciena switches will provide the backbone for 300,000 Cox San Diego telephone subscribers. The operator has two primary telecom facilities, in the north and south parts of the San Diego metro area.


About two years ago, Cox began looking for a replacement for the Nortel SONET equipment it used to interconnect the north and south metro network rings, because that vendor was phasing the gear out.

The CoreDirectors provide a “super-high-dense cross-connect,” Vaughn said. Each offers 640 Gigabits per second of bandwidth, of which Cox San Diego is using about 30 Gbps. The two switches are linked over dense-wavelength-division multiplexing (DWDM).

Vaughn and his team spent about eight months testing the units before they went live last fall.

Cox San Diego is now migrating connections from the SONET rings to the CoreDirector, a process Vaughn said is about 35% complete.

After the conversion is completed, the new switches will have freed up four racks of SONET gear and four racks of cross-connect panels for DS-3 (45 Mbps per connection) and T-1 (1.5 Mbps per connection) lines.

Vaughn declined to provide a price tag for the project, but he said the cost of the two Core­Directors was only slightly higher than deploying new SONET gear would have been.