November 4, 2008

Ethernet Reaches Cellular Backhaul

By Monta Monaco Hernon

On this election day, Ethernet might not be as hot a topic as the economy, taxation and Joe the plumber, but among cable operators, the technology is making headlines more frequently as talk turns into action on the commercial services front.

As Ethernet has gained momentum and credibility among cable operators, it has been parlayed into a mechanism for reaching a variety of niche markets under the commercial umbrella. Last week, CT's Pipeline reported on Time Warner's Ethernet over DOCSIS rollout. And now Aurora Networks has announced that its T-1/E-1 over Ethernet access solution has achieved Metro Eethernet Forum (MEF)-18 certification and will be generally available first quarter 2009. The GT3410A will be used to provide cell tower backhaul services and local loop access. (For more on the MEF and cellular backhaul, click here. For more on cell backhaul generally, click here.)

MEF-18 addresses circuit emulation services over Ethernet, which is used to link TDM and metro Ethernet networks.

"One of the attributes important to wireless backhaul is accuracy .... You need to run T-1 transport links for days, weeks and months without errors. MEF-18 tests for error-free transmission," said Luis Yu, Aurora Networks, senior product manager. He added that the GT3410A module can ensure latency of 1 ms or less, which he said is tight enough to support even the "most stringent" cellular technology.

"Multiple operators sometimes lease the same portion of the tower, and all want to have backhaul services. This solution is scalable in the sense that you have Gigabit Ethernet, which is plenty for all of the operators," Yu said. The T-1/E-1 ports are grouped in fours and can be chained together depending on how many each operator needs.

Local loop

A device like Aurora's emulates TDM circuits and packages synchronous T-1 transport so that it can be carried over Ethernet. At the other end, it is translated back into constant bit stream. This allows cable operators to offer legacy type commercial voice services because the Ethernet transport network can be connected directly to the customer's PBX through the device. It is "seamless" from the business' perspective, Yu said.

"Having laid fiber to a school (for example), the operator says, 'Why don't we also provide T-1 local loop service?' The GT3410A can deliver a 1,000 meg Ethernet connection to the school and provide T-1 service to connect the PBXs together," he said.

From an operator perspective, a solution like Aurora's is cost effective compared to buying SONET-based transport gear to provide the same type of services. From a capital perspective, the SONET alternative would be twice as expensive, Yu said. "The construction expense would be a fraction (of the cost) because you can leverage Ethernet transport and (leverage) existing fiber."

- Monta Monaco Hernon

Read more news and analysis on Communications Technology's Web site at www.cable360.net/ct/news/.