AT&T to deploy new gateway system
By STEPHEN HARDY
At&t (Morristown, NJ) may be the first carrier to deploy a new class of crossconnect system designed to ease the evolution to all-optical networks. With at&t`s stamp of approval on the concept, the system`s manufacturer, Alcatel Network Systems (Richardson, TX), hopes the system will be on the leading edge of a new networking trend.
The two companies recently signed a multiyear agreement that calls for at&t to test and deploy Alcatel`s new Optinex 1680 optical gateway crossconnect (ogx). The system operates in much the same fashion as traditional crossconnects, but will accommodate greatly increased traffic capacity. For example, the scalable system will support a total of 80 Gbits/sec to 2.56 Tbits/sec through anywhere from 32 to 1024 ports.
The system is a response to the increasing need to aggregate traffic into high-speed channels, such as OC-48 (2.5 Gbits/sec), before transmission over fiber-optic transport networks, according to Fred Ellefson, senior director of marketing and business development at Alcatel. "In the decade from 2000 to 2010, the transport network is now going to run at the OC-48, the OC-192 [10-Gbit/sec], and the OC-768 [40-Gbit/sec] rates. And most of the traffic now is stuck down at the DS-3 [44.736-Mbit/sec] rate, which is where transport used to start from. So now you need a way to get from DS-3 to OC-48, or DS-3 to OC-192, or DS-3 to OC-768. Because before you go and wdm [wavelength-division multiplex] stuff and use optical crossconnects, you`re going to make sure that you`ve got the biggest electrical pipe that you can," he explains. "And so this optical gateway basically takes you out of the sonet [Synchronous Optical Network] electrical or asynch electrical domain and launches you into the optical layer at OC-48 and above."
Currently, add/drop multiplexers perform this kind of traffic aggregation. "But if you think back to the [early] `90s, we had M13s that did that [at lower speeds] as well," Ellefson says. "But what you found was that as your network grew, it didn`t make sense to have 242 M13s at a site; you put in a crossconnect instead."
Thus, Alcatel is betting that as network capacity increases, carriers will not want to buy the large number of add/drop multiplexers that might be necessary to keep pace.
"If you look at the broadband crossconnect market and the evolution that we`re about to go through, most of the broadband crossconnects that are deployed today are used for restoration," says Ellefson. "The at&t and mci networks, when you get a fiber cut, they`ll route around them using a broadband crossconnect. But going forward, in the next decade I think we`re going to see the role of these broadband crossconnects evolve from being a restoration vehicle to being more of a multiplexing and, as we call it, a gateway between the sonet layer and the optical layer."
at&t is already anticipating this trend as it attempts to cope with its increasing capacity demands, says Ellefson. Thus, the carrier asked for a robust crossconnect capable of handling greater speeds. Alcatel plans to deliver the first units of the crossconnect late this year. at&t will conduct lab evaluations through the beginning of next year, after which deployment into the network is expected. In addition to supporting sonet traffic, the system also will accommodate cell-based transmission schemes such as Asynchronous Transfer Mode and Internet protocol.
at&t`s application of the ogx will include the Alcatel 1320 NM network manager. The Telecommunications Management Network-based system will enable the ogx to be integrated with at&t`s existing network management systems. q