CRS-1: Cisco’s huge router reaches five-year milestone

Cisco introduced the CRS-1 (Carrier Routing System) on May 25, 2004, as its first multichassis core router platform. The numbers were impressive: Fully configured, the system would have 72 racks of network interface modules and eight racks of interconnecting “fabric” modules, all acting as a single router with 92Tb per second (Tbps) of capacity. In the four-year development of the CRS-1, Cisco even created a new version of its IOS (Internetwork Operating System) software, called IOS XR. The new OS shared elements with the traditional IOS, including its venerable command-line interface, but had a modular architecture for high availability.

Five years later, Cisco’s predictions of high-definition online video and ever-growing demand for Internet capacity have come true, and big carriers including AT&T, Verizon Wireless, China Telecom, Telstra, Comcast and BT Group all have deployed CRS-1s, according to Cisco. But the rising tide has lifted rival Juniper Networks’ core routers even more than Cisco’s, and China’s Huawei Technologies is making inroads in the lower end of the market, according to one analyst.

The CRS-1 came in the wake of Juniper Networks’ T Series routers and TX Matrix interconnection system, another big multichassis platform for the core of carrier networks. It also emerged after several startups, including Caspian Networks and Procket Networks, had tried to jump into the big-money business of supplying the biggest routers on the Internet amid a historic telecommunication crash. Shortly after introducing the CRS-1, Cisco announced it was buying Procket’s assets.

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Calin is a network engineer, with more than 20 years of experience in designing, installing, troubleshooting, and maintaining large enterprise WAN and LAN networks.

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