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.
RELATED LINKS
Introduction to WDM and related topics, from IBM.
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.
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