Vendors demonstrate optical provisioning from Internet-protocol layer

By STEPHEN HARDY

The current vision of tomorrow's optical core generally calls for Layer 3 switch/routers to push Internet-protocol (IP) traffic across dynamically provisioned optical pipes provided by a new generation of optical-networking equipment. While the systems required to fulfill this vision have begun to appear, the drive to get them to work together has not progressed beyond discussions within such industry groups as the Optical Internetworking Forum (OIF) and the Optical Domain Service Inter connect (ODSI) coalition-at least until recently. A pair of vendors took the opportunity afforded by the recent Conference on Optical Fiber Com munications (OFC 2000) to demonstrate how such dynamic provisioning might be accomplished.

The demonstrations comprised Tera bit Switch Routers (TSRs) from Avici Systems Inc. (North Billerica, MA) working with Aurora 32 optical switches from Tellium Inc. (Oceanport, NJ). The two companies strung three fiber pairs between their booths; each booth contained a TSR and an Aurora 32. The companies configured the mini-network to transmit a pair of OC-48 (2.5-Gbit/sec) links between the booths as the "base" traffic level. In the demonstration, a third OC-48 link was added to the access side of the network, attempting to run through one of the TSRs. The TSR sensed that it needed an extra link between the booths and alerted its companion Aurora 32 switch, which established the link. When the added access link was shut off, the extra connection between the booths was terminated automatically.

The two companies touted the demonstration as proof that running IP directly over the optical layer with flexible bandwidth provisioning could enable carriers to avoid having to hardwire capacity at peak demand levels. Such flexible provisioning would enable carriers to accommodate unexpected traffic surges as well as the addition of new services or customers.

Nick DeVito, vice president of product management and business development at Tellium, says the demonstration took about six weeks to put together-but would require another six months to polish properly for a customer trial. That said, Williams Communications is expected to give the combination a spin in its Terabit Test Bed project.

DeVito reveals that the interoperability demonstrated with Avici could not be immediately replicated with other switch/router vendors and that Tellium was not interested in pursuing a proprietary interoperability technology. An "open systems" approach to interoperability is the goal of both the OIF and ODSI, and sources at Avici and Tellium say they plan to share the results of their efforts with interested industry groups.

With at least two industry groups (the Internet Engineering Task Force is another possibility) and now vendors working independently on the problem of interoperability between the IP and optical layers, the industry appears on the verge of developing competing strategies. Carl Russo, vice president and general manager of the Optical Networking Group at Cisco Systems Inc. (San Jose, CA), says that demonstrations such as the one conducted by Avici and Tellium may spur the industry organizations to move more quickly in developing common ground. With Cisco being a member of the OIF, Russo believes that organization is the organization best suited to develop an open interoperability scheme.

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