Direct Connection: Vendors link switching, routing equipment directly to WDM systems

A pair of announcements last week highlighted what likely will be an important step as networking evolves toward optimization for data traffic.

Bay Networks, Cambrian Systems, 3Com and Packet Engines will jointly demonstrate a gigabit Ethernet-to-dense wavelength division multiplexing (DWDM) direct link at Networld+Interop. Ciena Corp. and Cisco Systems have signed an agreement to develop direct connections between Cisco switch routers and Ciena DWDM systems.

The Cambrian group is touting its demonstration as revolutionary because it will allow LAN users to send data traffic between distant sites without converting it from gigabit Ethernet to a WAN-friendly format. Service providers delivering private networks can offer end-to-end native Internet protocol (IP). Cambrian is supplying the DWDM component.

The project is the culmination of an interface development program for Cambrian, said Solomon Wong, Cambrian's assistant vice president of marketing. "We started developing products with the capability of developing interfaces to accommodate other technologies," he said. The interface will support direct connections with other protocols, but gigabit Ethernet will provide new alternatives for carriers and end-users, Wong added. "This moves [gigabit Ethernet] from just enterprise, single-building solutions to campus or [metropolitan area network] applications," he said.

The demonstration will employ Bay's Accelar 1200 routing switch, 3Com's SuperStack II Switch 9300 and Packet Engines' PowerRail 5200 enterprise routing switch and will simulate traffic between two buildings at least 20 miles apart.

"We've been working for a long time, looking at bringing IP as close to the transmission system as possible," said Richard Pearce, business development director for Bay's Internet Telecommunications Business Group. Those initiatives have included integrating a Bay router into another vendor's Sonet multiplexer, but the direct-to-WDM link is a breakthrough step. "It opens a lot of potential to run enterprise-type applications over a broad area," he said.

Although similar, the Cisco and Ciena initiative is not as aggressive in terms of a new interface. Their project will focus on directly connecting the Sonet interfaces on the router and the WDM system as opposed to running all traffic through a Sonet multiplexer.

"We've been looking at open interfaces using standard OC-48 and Sonet," said Denny Bilter, Ciena's marketing director. "This is a culmination of what we've been promoting-plugging different types of equipment [into the WDM system] rather than having a proprietary system. There will be a host of other vendors going straight to the glass rather than through a Sonet multiplexer."

The direct connection between router and WDM is straightforward for point-to-point fiber exhaust applications, said Graeme Fraser, vice president and general manager of Cisco's Internet service provider business unit. But as wavelength deployments become more complex and service-oriented, the direct link becomes more complex.

"It's possible to connect the router to the WDM terminal, but that doesn't address restoration and topology," he said. "A lot of the work we're doing is integrating those functions of Sonet into the router."

Direct-to-WDM initiatives will play a key role in the development of voice over IP, said Mike Arellano, president of Degas Communications Group.

"If voice over IP actually starts going everywhere, and if the public network is going to go from a circuit-switched to packet-switched architecture, you're going to need these types of devices," he said. "If you can put a switch router directly into a high-speed optical system, that's a step toward allowing voice over IP to work."