Qtera Proposes Router-Friendly Optical Transport

By: Erik Kreifeldt

Although the company is not prepared to reveal the specifics of its technology, Qtera Corp. (Boca Raton, FL) is staking its claim as a transparent optical transport network player that supports a core router-based network architecture. Following the current generation of "opaque" optical cross-connect strategies, Qtera plans to deliver more optically transparent transport products next year that optimize bandwidth, distance, and survivability in long-haul, high-capacity networks.

The primary objectives of a long-haul network backbone are to deliver low-cost, survivable bandwidth and rapid service provisioning, says Fahri Diner, Qtera's founder and CEO. Qtera intends to accomplish those objectives with an optical transport platform with physical-layer restoration that interfaces directly with core routers.

The problem with a router-centric transport network architecture, where a core router serves as the convergence point for network traffic, is the mammoth processing power necessary to groom and protect high-bandwidth traffic on a national scale. "With Qtera equipment, the router will only have to do routing. Processing is only a problem when you require the router to do restoration," Diner says. "We relieve the router of this restoration requirement—that's what makes this vision feasible."

Long-haul transparency
Qtera also plans to deliver transparent optical paths at network nodes for express traffic, further reducing the processing burden on routers. "We ride on top of a terabit router—we pass right through," Diner says, using "purely photonic" methods of wavelength management. To solve the problems posed by national-scale transparent networking identified by long-haul operators such as AT&T (New York, NY), Qtera is also working on ultra-long distance, nonregenerated transmission.

In the IP-over-optics model, synchronous optical network (SONET) functions are reduced to a thin layer of framing, sans the add/drop multiplexer (ADM). But the near-term alternatives to a SONET ADM just introduce a different box, albeit a cheaper one, Diner notes. Qtera will avoid introducing another network element to replace SONET ADMs between IP routers and the photonic network layer, he says.

Efficiency versus complexity
Instead of engineering for maximum bandwidth efficiency, Diner proposes a trade-off for simple restoration architecture. "We use bandwidth somewhat inefficiently, but we make it abundant and cheap," he says. "We're trading in complexity for bandwidth."

As optical networking startups such as Lightera and Monterey emerge with "opaque" cross connects that groom traffic in STS-1 (52 Mb/s) channels and higher with electrical switch fabrics, Qtera plans to offer a more optical method of wavelength management. The cost of Qtera's loftier goal is roughly a year's time-to-market disadvantage—it plans to have a commercially viable product in 2000.

By the time Qtera has products available, it plans to have the lowest-cost transport solution with the fastest restoration and "almost infinite" scalability. "Our networking solutions will provide at least an order of magnitude reduction in providing survivable bandwidth," Diner concludes.

Qtera has assembled optics luminaries from Siemens (Boca Raton, FL), Pirelli (Lexington, SC), Alcatel (Richardson, TX), MCI WorldCom (Jackson, MS), Uniphase (San Jose, CA), and a second round of financing of $32 million, totaling $43 million. Investors include Battery Ventures, Oak Investment Partners, VantagePoint Venture Partners, the Mayfield Fund, and CommVest LLC. Diner's most recent endeavor was helping to establish the optical networks business unit for Siemens Information and Communications Networks. He previously worked with Pirelli Cables & Systems.