Optical/IP Networks

Ciena Claims DWDM Coup

Ciena Corp. (Nasdaq: CIEN) has produced what it claims is the most flexible DWDM platform to date, offering the ability to run arbitrary protocols and line speeds from a generic line card.

If that's true, then the FlexSelect architecture, being launched today, is a major step forward in the "any service, any port" mantra that's being chanted by nearly every optical vendor. In general, Wavelength Division Multiplexing (WDM) vendors have been making interfaces increasingly flexible, but Ciena says it goes beyond anything produced by competitors such as ADVA Optical Networking (Frankfurt: ADV), Alcatel (NYSE: ALA; Paris: CGEP:PA), Cisco Systems Inc. (Nasdaq: CSCO), and Nortel Networks Ltd. (NYSE/Toronto: NT).

Ciena's claims will face their first test with the CN 4200, a 24-slot chassis that's the first system in the FlexSelect fold (see Ciena Launches FlexSelect). It's already gotten two votes of approval, having won deals with BT Group plc (NYSE: BT; London: BTA) for its 21CN network and Swisscom AG.

For the past few years, the optical transport market has seemingly progressed with all the speed of a German art flick. But even so, optical technology continued advancing, and carriers today are awash with new capabilities to consider (see Optical Networking: All Grown Up).

Enter FlexSelect, which Ciena believes is as large a step as the introduction of CoreDirector, the company's flagship product. CoreDirector added smarts to optical transport by deciding where in the network to send TDM traffic, much the way a router decides where to forward Internet Protocol (IP) traffic.

The key to FlexSelect is a programmable framer, which allows a line card to change personalities among options including Fast Ethernet, 10-Gbit/s Ethernet, OC3, OC192, Fibre Channel, and the venerable Escon. Changes are made remotely and nearly instantly using pull-down menus. The FlexSelect operating system then establishes the new path for the traffic -- ideally, in Ciena officials' minds, using CoreDirectors to negotiate the path -- and enforces any service-level agreements in place.

The CN 4200 can also work in subwavelengths, using digital wrapper technology to pack multiple traffic feeds into one wavelength.

The FlexSelect technology originated at Internet Photonics, which Ciena acquired last May for $149 million (see Ciena Buys More Than Catena ). But much of what's being released today was developed after Ciena acquired that company, says Tom Mock, Ciena's senior vice president of strategic planning.

Some of FlexSelect's capabilities are already established in competitors' products. Nortel's OM 5000, for example, offers a four-port card that packs multiple traffic streams into one 1.25-Gbit/s wavelength.

Likewise, Release 5.0 of Cisco's DWDM software added an "any service, any port" feature, with one set of optics able to handle OC3, OC12, OC48, or Gigabit Ethernet. That capability comes from the programmable nature of the pluggable optics Cisco has begun using in DWDM. "Every board we design uses pluggable optics at this point," says Rajiv Ramaswami, vice president of Cicso's optical division (see DWDM Goes Pluggable).

Similarly, Alcatel has long supported a "4xAny" technology in its metro equipment. This enables up to four different protocols to be multiplexed onto a single wavelength (see Alcatel Intros Metro DWDM Gear and Alcatel Spruces Up SDH Box).

But other platforms' flexibility has limitations, notably in needing different line cards to support different protocols, Mock says. Ciena is preaching the use of a generic line card to carry pretty much anything.

"Ciena does seem to have taken that flexibility to a new level," says Sterling Perrin, an analyst with IDC.

That doesn't mean FlexSelect is the last word in DWDM flexibility. Ciena used FPGAs to give the architecture its programmability, claiming that network processors couldn't keep up with newer protocols that are in flux. That decision seems to leave open the possibility of some silicon advances. "In general, IDC is seeing a trend towards network processors in next-generation telecom products, so I think we'll see more" boxes with similar flexibility, Perrin says.

Aside from giving Ciena some features to brag about, FlexSelect provides ammunition against some recent challenges to classic DWDM.

First, and more specifically, Ciena now has a response to hot-shot startup Infinera Inc., whose DTN system combines DWDM with add-drop multiplexing capabilities (see Infinera Declares WDM War). The DTN offers flexibility in add/drop assignments, but it's also capable of grooming and multiplexing traffic.

A more widespread challenge -- one that targets Ciena's older installed base -- is the idea of "collapsing" the Sonet layer, running traffic directly over DWDM wavelengths. The concept was popular during the bubble as a way to simplify carrier networks, but the buzz surrounding it dwindled after the crash. Now, vendors including Cisco have reignited the idea, catering in part to cable MSOs that need additional network builds but don't have the Sonet/SDH baggage of the telecom carriers.

Should Sonet liquidation catch on, Ciena can pitch systems like the CN 4200 for the job, because they allow carriers to start with a bevy of Sonet ports and tune them to Ethernet as needed, Mock says. This gives Ciena a play for helping carriers ease into the Sonetless world. "We see [Ethernet-over-optical] as the underpinning for most of the transport services that will be offered," Mock says, pointing to IPTV in particular.

Ciena also sees potential for FlexSelect to go beyond carrier networks and into government and enterprise networks. "There's a fairly large first-time buyer market in the enterprise that finds value in the CN 4200 architecture," Mock says. "It gives them the look and feel of what they've been getting from the carrier."

— Craig Matsumoto, Senior Editor, Light Reading

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