Cisco prepping router for terabit speeds

Cisco Systems Inc.'s new terabit router will be based on the same architecture as the company's existing gigabit routers.

Next year, Cisco will unveil 10G-bit-per-second OC-192 interfaces for its 12000 series Gigabit Switch Router, which will begin the GSR's metamorphosis into a terabit switching router, said Graeme Fraser, vice president and general manager of Cisco's ISP business unit. Fraser discussed Cisco's plans two weeks ago at the NetWorld+Interop 98.

"We are going to base [terabit routing] on the GSR," Fraser said. "We plan to upgrade [the GSR] next year with 10G-bps line cards for 250G bps of overall capacity [and] to scale beyond that for multiterabits."

Terabit routing provides the speed many industry experts say is necessary for scaling the Internet into the next decade and providing a new class of data services to end users. Several router startups are designing terabit routers.

Many of the startups, however, say that a crossbar switching fabric - which is at the heart of Cisco's GSR - is inadequate for scaling the Internet to terabit speeds. Specifically, detractors say because crossbar fabrics employ input queuing, they are insufficient for IP multicast applications and are susceptible to head-of-line blocking.

But Cisco claims to have cured the multicast and head-of-line blocking issues of crossbar switches with the GSR. For multicast, the GSR employs a patented output-scheduling algorithm for recognizing and queuing multicast packets, Fraser said. And the GSR employs a technique Cisco calls "virtual output queuing" to alleviate head-of-line blocking.

Another technology that will help scale the GSR is wave-division multiplexing (WDM). WDM is said to provide increased bandwidth efficiency, and eliminates the cost and bandwidth limitations of time-division multiplexing (TDM), which is employed in existing Synchronous Optical Network (SONET) infrastructures. To connect the GSR to WDM gear, Cisco is developing a concatenated OC-48 interface. A concatenated interface statistically multiplexes packets and cells over optical wavelengths and uses all of the 2.5G bps available in an OC-48 trunk.

Optoelectronics
White paper on wave division multiplexing from Scientific Atlanta.

Cisco details optical networking strategy
Network World Fusion, 4/21/98.

Cisco unveils new high-speed GSR
Network World, 1/14/98.

Parallel processing boosts router performance
Network World, 3/30/98.

Router start-up going for terabit speed
A look at Nexabit. Network World Fusion, 3/24/98.

Avici offers glimpse into its really big router
Another terabit device. Network World, 1/12/98.

The really big router battle
A look at terabit startups trying to take down Cisco. Network World, 12/29/97.