For a mere half a million bucks and up, you can’t expect sex appeal. Cisco’s Carrier Routing System-1 is the size of a refrigerator and considerably less appealing to the eye. Debuting late last month, it’s a rackful of hardware and software customized for one job alone: Running the future Internet.

The CRS-1 and rival super-routers are at the other end of the spectrum from the little wireless black box that connects your home PCs to the Internet. And they’re a giant leap up from most of the routers that run corporate networks and the Internet itself (and that turned Cisco Systems into one of the most heavily capitalized corporations of all time). How different? For one thing, Cisco has thrown a massively parallel supercomputer at the challenge of running big networks. Instead of, say, modeling weather data, the CRS-1 is riding herd on mountains of 40-gigabit-per-second fiberoptic network connections. Cisco built what it calls the world’s most advanced custom silicon chip, dubbed the Silicon Packet Processor, to make decisions about how the system flings communication packets across a network. Each chip contains 188 32-bit processors, each with its own protected memory and all working in parallel. A large CRS-1 system can hold hundreds of the chips.

The CRS-1 also stands out for sheer throughput. An individual router can handle 1.2 terabits per second, and 80 routers can be clustered together to provide up to 92 terabits per second. That’s enough, Cisco points out, to deliver an 850 kilobit-per-second connection to every house in the United States or zap a digital version of the Library of Congress to you in less than five seconds. And it’s 70 times faster than the company’s previous best router, which topped out at 1.3 terabits per second.

But far more critical, analysts say, is the reliability and manageability that CRS-1 promises. That Niagara of bandwidth flowing through all those shelves of equipment is all channeled within a single system, running under a new, modular, ultra-reliable operating system. Tasks are distributed flexibly across processors, and a glitch in one operation can be overcome automatically without bringing down the entire router. That way, different processors can run different Internet protocols without stepping on each other. The overall approach “is a fully distributed system that is the network equivalent of grid computing,” says Robert Whiteley, an analyst at Forrester Research.

The result, Cisco declares, is a system that can run for more than a decade without stopping. (Mere mortals who shy from the command-line interfaces that earlier Cisco routers provided will appreciate that the company threw in a graphical user interface for managing this mother of all routers.)

Cisco spent four years and half a billion dollars to develop the CRS-1, most of it devoted to refining the new operating system. “There’s been a lot of talk about making the Internet infrastructure as reliable as the phone system,” says Whitely. “This is one of the first products that starts to deliver on that promise. Its lifespan should be measured in decades, rather than the five years that’s typical for routers.”

Despite its strengths and Cisco’s market-leading position, the CRS-1 will get fierce competition. “These are very complicated products, and Cisco is leading in some technologies but not all,” says Yankee Group analyst Mark Bieberich. Juniper Networks, Avici Systems, and other vendors remain serious rivals. With the technologies advancing so quickly, Bieberich says, suppliers keep leapfrogging each other.

All these systems “are key to building the converged networks that everyone has been talking about, with voice, video, and data all delivered via IP,” Whitely says.

Cisco ads promoting the CRS-1 ask, “What would you do with 90 terabits per second?” It’s an excellent question (after you download the Library of Congress, what do you do for the next five seconds?). And jokesters at the Slashdot geek site are offering plenty of suggestions (one sample: “such routers need to be installed in every home to allow the downloading of [Windows] patches).

Actually, you need to be a Sprint or MCI to profit from a CRS-1. And even such big guns may be slow to buy equipment with these ultra-high-end capabilities, since most currently aren’t spending much on major infrastructure initiatives, says Whitely.

But in a few years, this next generation of routers will form the backbone of an Internet on which service providers offer every digital amenity we can imagine. They’ll build it, and we’ll come.