Core routers: The path to cloud, content delivery network services?

Does more traffic require bigger core routers? As content delivery network (CDN) services push content closer to the edge, core network investment may become secondary.

Does traffic growth dictate the need for bigger core routers? Cisco Systems' much-hyped release for its latest souped-up core router, the CRS-3, may lead carriers to think so. But as content delivery network (CDN) services enable operators to push content closer to the edge, the almighty core may become a shadow of its former self.

Our IP backbone is a critical link to support all this growth for both our wired traffic and increasingly for these mobile broadband applications.

Keith Cambron
President and CEO, AT&T Labs

"The Internet is becoming more and more an access process, and less and less a core process. Even the products that are called 'core routers' are usually used as on-ramps [to CDN providers'] data centers," said consultant Tom Nolle, president of CIMI Corp. "The Internet is turning into something else under pressure for content distribution … a federation of metro networks."

CDN service providers -- Akamai Technologies probably the best known among them -- cache popular content within metro areas, meaning that customers aren't going back and forth over the Internet backbone to get to Netflix's data centers for every high-definition video they stream, Nolle said.

"The notion that more traffic implies more routers is not necessarily true because all of the traffic that's generated doesn't have to pass through any common set of devices," he said. "If you watch a movie online and I watch a movie online, it's very likely there isn't a single shred of infrastructure on this planet that carries our traffic together … [because] we're in different metro areas."

Although it's faster and cheaper for operators to carry traffic on an optical transport network versus Layer 3 switching with routers, core routers are not becoming extinct, according to Michael Howard, cofounder and principal analyst at Infonetics.

"Most of the router intelligence goes to the edge, and most of the core traffic is carried on optical networks. People have been saying that for a long time," Howard said. "But still, the core router's never going to go away.... You have to have some machine to process IP packets."

But until IP video becomes profitable, upgrading to more expensive and powerful core routers may not yet be worth the investment for carriers, according to Nolle.

"Traffic transport is not a divine right, meaning that service providers are going to expand networks and build out infrastructure to the extent that it's profitable," he said. "The notion that traffic drives network deployment is not correct. Revenue drives network deployment."

Investment in core routers may still have its place

But big box vendors disagree. During a live webcast last week, Cisco CEO John Chambers touted the CRS-3 -- which has a starting price of $90,000 and, if strung together with 72 interconnected chassis, can gallop at 322 Tbps -- as "the foundation of the next-generation Internet." 

It's a hypothetical maximum, however, since "no operator in the world ... would ever think about putting 72 routers together in a single node," Howard said.

"The truth is I think the largest single node of interconnected routers ... I'm aware of is six, and the most frequent multi-chassis [deployment] is two," he said.

Last Feburary, Juniper Networks threw a similar punch with its T-Series core routers, which are claimed to reach up to 4 Tbps -- about 8 Gbps behind Cisco's CRS-3 but in half the rack space.

"There's a delicate balance. On one hand, you'd like to push the CDN video close to the subscriber," said Mallik Tatipamula, vice president of service provider business at Juniper. "On the other hand, there is such traffic as peer-to-peer or over-the-top that is still consuming a lot of bandwidth within the [Internet] backbone, and the core needs to be upgraded to accommodate."

So far, the top two North American Tier 1 carriers are sold on the idea. Juniper recently announced that Verizon has installed its T1600 core router to achieve 100 Gbps on its backbone in Texas. Keith Cambron, president and CEO of AT&T Labs, said the operator had chosen the CRS-3 to complete its 100-gig test between New Orleans and Miami.

"Our IP backbone is a critical link to support all this growth for both our wired traffic and increasingly for these mobile broadband applications," Cambron said during the Cisco webcast.

Using powerful core routers to get into the cloud services business

Although it was the CRS-3's speed that grabbed the spotlight last week, the software it supports is what will enable carriers to monetize their investment in the core, according to Mike Capuano, director of service provider marketing for routing and switching products at Cisco.

The vendor's two-pronged Data Center Services System (DSS) enables carriers to take a step toward competing in the cloud provider market by automating the routing, Capuano said.

Half of DSS is its Network Positioning System, which enables the CRS-3 to respond to a cloud service request from an enterprise customer's data center infrastructure by connecting it to the operator's closest data center with those resources. Carriers have had to manually configure these connections or use techniques that lacked intelligent routing, Capuano said.

The other piece of DSS is what Cisco calls its Cloud VPN capability, which drills the secure tunnel for enterprise customers to extend their multiprotocol label switching (MPLS) network into carrier cloud resources.

"A lot of focus is put on how fast the access [network] is. Access is as good as the core and the edge of the network," said Suraj Shetty, vice president of marketing for Cisco's service provider unit, during the webcast. "I think the core becomes one of the primary drivers of [what] the next-generation Internet looks like."

Let us know what you think about the story; email: Jessica Scarpati, News Writer

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