Full Story Full Story


A New Era for Communications Begins with CRS-1

Cisco builds a networking router of unprecedented performance and intelligence to run the infrastructure for the Information Age

May 25, 2004

By Charles Waltner, News@Cisco

It took over four years, half a billion dollars, and 500 engineers to build. But no one said creating the future of communications would be easy.

And for Cisco Systems, the future of communications is the Cisco Carrier Routing System (CRS-1), the most ambitious project the company has ever undertaken. But the results have been worth the effort. The CRS-1 is a router of unprecedented power and sophistication for running the infrastructure of the Information Age; a router capable of completing the transition from the era of the telephone to the era of the Internet.

"Every carrier has been telling us they want to move to an IP-based converged packet infrastructure," says Tony Bates, the architect of the CRS-1 and the vice president and general manager of Cisco's Carrier Core and Multiservice business unit. "This wasn't something Cisco just thought up as neat technology. It was what our customers, the world's leading telecommunications companies, were saying they needed. They weren't worried about the technical difficulties of making such a device. They left that challenge to us."

The CRS-1 is a new class of router system Cisco custom-built from the ground up to consolidate all voice, video, and data traffic onto a single network infrastructure based on Internet protocol (IP) technology. The CRS-1 offers the bullet-proof reliability that major telecommunications companies have come to expect from their phone systems, as well as the revolutionary capabilities delivered by Internet communications, all combined on a machine that is vastly more powerful, more expandable and more intelligent than any router ever created.

The CRS-1 can transmit information four times more rapidly and can expand to 100 times more overall capacity than any router in the industry. And it provides an array of features and controls far beyond previous benchmarks. With such capabilities, the CRS-1 will be able to lead the transition to IP-based communications over the next 10 to 15 years.

Without a doubt, building CRS-1 required Cisco to tap every bit and byte of experience it has gained over the last 20 years as the leading maker of IP-based networking equipment.

"This was a product that could have only been created from the roots and heritage of Cisco itself," Bates says.

The idea for the CRS-1 started at a time before the bursting of the dot.com bubble, a time when the Internet was reputed to be growing as much as 10-fold a year. Cisco executives looked to Bates to come up with the basic principles and design parameters for a router that could deliver all the power, expandability, dependability, and flexibility to handle the incredible changes the Internet was forcing on telecommunications networks. Though times have changed, these companies still face a variety of challenges from waning phone service revenues, limited and expensive to maintain multiple legacy networks, continually advancing technologies, and, still, Internet growth.

Despite slowing down since the late 1990s, the Internet continues expanding every year. At the same time, individuals and businesses are demanding more and more bandwidth to run new communications options, such as desktop video conferencing, IP telephony, and remote storage. Soon connections 10 times faster than today's DSL and cable modems will be the required norm.

After Bates spent 90 days in early 2000 establishing the basic principles for the CRS-1, he launched the project and formed his team. The project drew on Cisco's best and brightest minds. Certainly, Bates is no stranger to pioneering Internet development. Before joining Cisco in 1996, he helped create Europe's first pan-continental IP network as well as spearheading Internet MCI, one of the world's first commercial branches of the Internet.

The CRS-1 was a global effort, with members of the 500-person team heralding from the four-corners of the world, including Israel, Canada, England, India, Scotland, and a half-dozen cities in the United States.

Bates' right hand on the project was Dan Lenoski, the CRS-1's vice president of engineering. Lenoski, in particular, brought invaluable insight as a 23-year industry veteran who has helped pioneer the world's most powerful computers for Silicon Graphics, Sun Microsystems and Tandem. Lenoski's experience was particularly valuable in guiding such an ambitious project that pushed the limits of technology on so many fronts.

"Dan really knew what it took to build such a complex machine," says David Ward, the lead software architect for the CRS-1. "He's done so many big projects like this so many times before that he knew how to strike the balance between what the engineers wanted to do and the practical limits of getting all the pieces to work together."

Certainly, over the course of the project, the CRS-1 team had to make hundreds of decisions about how to invent this new networking device. One philosophy, however, guided the entire project.

"We were committed to taking every aspect of the CRS-1 as far as it could go," Bates says.

Such creative carte blanche led the CRS-1 team to several industry firsts in router design. Most importantly they built the CRS-1 as a system rather than an individual router. Unlike typical routers, the CRS-1 is a highly distributed and modular machine. Its basic building block is a chassis that can process 1.2 trillion bits of data per second. But then additional chassis can be seamlessly added to expand the machine to as much as 92 trillion bits of capacity. With such power, a single CRS-1 system can provide an 850 kilobit-per-second (Kbps) connection to every household in the United States, transfer the entire collection of the U.S. Library of Congress in 4.6 seconds, or connect 3 billion telephone calls during the blink of an eye. Such capability makes crystal clear video and audio over the Internet as simple as picking up the phone.

Uniquely, such expansion does not lead to greater management complexity. All the connected chassis runs as one machine, sharing the same operating system, computing resources and other management functions. Also, the CRS-1's distributed architecture spreads out its computing power and functions among various microprocessors, so that no one part of the machine can cause a bottleneck. And the CRS-1's modularity provides tremendous adaptability and flexibility, allowing network managers to add new components incrementally for "pay as you grow" capacity and feature expansion.

"The idea is to turn the system on once and have it run for years, regardless of how many times it's reconfigured, upgraded or worked on," Lenoski says. "That's the Bell phone system model that traditional telecommunication companies have come to expect; extremely dependable and durable equipment. You never have to take it down, at least for a decade or more."

The CRS-1 can thank its innovative "microkernel" operating system for much of its flexibility. This new operating system, called IOS XR, is the first time in Cisco's history the company has created a new operating system since the original IOS debuted 20 years ago. IOS XR is based on a software architecture that breaks the operating system into discrete components, or modules, which are distributed throughout the router system to run such operations as memory management, application support, and system data-basing. This means that the CRS-1 can keep working even if a glitch stops one part of a process. Correspondingly, the microkernel design means network operators can perform upgrades and maintenance on one part of the machine without having to take the device offline, as well as running multiple functions or applications simultaneously without worries of one application affecting the performance of another one.

Cisco's no-holds-barred approach to creating the CRS-1 also inspired several breakthroughs in semiconductor technology. Perhaps most impressive of the eight chips Cisco developed for the CRS-1 is the Silicon Packet Processor (SPP), which runs many of the router's decision-making functions for directing communications packets across a network. Collaborating with chip manufacturing partner IBM, Cisco designed the world's most advanced custom silicon chip, which contains 188 32-bit processors functioning in parallel. A large CRS-1 contains hundreds of these SPPs, making the device a true supercomputer of routing.

"When we first talked to various people about this parallel chip design for the routing system, they asked 'Are you going to run 16 or 32 processors in parallel?" and we would say, 'No, it's closer to 200," Lenoski says. "Well, you know, that caused more than a few jaws to drop."

Certainly, it was Cisco's intent to garner such a response from its customers, and it took no risks in this regard. Cisco designed the CRS-1 in close consultation with telecommunication companies. Now the CRS-1 is the router they had been hoping for.

The CRS-1 will let carriers confidently migrate all of their existing communications infrastructures for voice, video, and data onto a single, packet infrastructure, helping greatly reduce capital costs and operating expenses. At the same time, the CRS-1 will make possible a much broader range of applications than we experience today, especially any video or graphics-based ones demanding of bandwidth.

Though a thrilling adventure to work on the edge of technology, Bates and the rest of his team say building the CRS-1 presented by far the most formidable challenges of their careers. Terms such as "daunting" and "scary" are often uttered when discussing the topic.

"This was like climbing Everest," Bates says. "It was a long, arduous endeavor, and I needed to be like a shepherd, helping people along, pointing the way, and keeping spirits up, because, to be frank, on a long project like this with so many technical barriers, people can get burned out. But we all hung tough and, of course, reaching the goal makes all the toil worth it."

Now the CRS-1 team hopes they have created something not just for today but also for another generation.

"At the start of the project, my son was one-and-a-half years old," Bates says. "To motivate the team, I told them I wanted the CRS-1 ready for him when he begins using the Internet. And in many ways, we were building this CRS-1 for everyone's children. Cisco believes this will be the router that will help telecommunications companies deliver on the promise of the multimedia communications future. That means sparkling video, crystal clear audio, rich graphics and applications not even dreamed of yet. Like the phone today, we shouldn't have to think about whether the network can handle a particular communications method. It should just work. Our next generation is growing up with the Internet, and the CRS-1 will let them use it to its ultimate capability."

Charles Waltner is a freelance journalist in Oakland, CA.

Web Content Display Web Content Display


Web Content Display Web Content Display

Stay Connected

Web Content Display Web Content Display

The Network is offering Google Translate in an effort to more easily share our content with a global audience. As these are free, machine translations, we cannot verify that all translations are accurate.


Web Content Display Web Content Display

Web Content Display Web Content Display
Web Content Display Web Content Display
Web Content Display Web Content Display