MPLS is a complicated technology, and complication could be another factor that's limiting the scalability of the Internet, McQuillan says.
"Service providers can't hire enough people," he says. "It's cool to build the latest, biggest and baddest box, but connecting it to everything else is a limiting factor."
In addition to scale, stability of routing iis another concern in growing the 'Net and making it a reliable infrastructure for daily communication, research and commercial use. Routing table sizes and update intervals are of particular concern, says William Norton, co-founder and chief technical liaison of service provider Equinix.
"The propagation of [Border Gateway Protocol] is a cause for great concern," Norton says, referring to the routing protocol used in the Internet. "You have to wait 15 minutes for updates. Can you imagine talking on the phone and waiting 15 minutes for a response?"
But routing is needed for its ability to inspect packets and request or provision bandwidth. If optics are needed for scale, is an intelligent, all-optical 'Net possible?
"We don't have a way optically to tell you what the bits are," says Stephen Alexander, senior vice president and chief technology officer at Ciena. "If you need to know what the bits are, you need electronics."
Alexander does not believe integrating routing and dense wave division multiplexing is the answer.
"We're not big fans of the 'God box,' " a product that is touted to do everything, he says. "There's a reason your car doesn't fly and float."
McQuillan suggests it may be time for the industry to conceive new routing algorithms that are optimized for scale and optics. Others propose that today's core routers will soon be obsolete.
"Packet routers as we know them today will be dead in 18 months," says Lawrence Roberts, chairman and chief technical officer of Caspian Networks. "They need to be vastly more intelligent to solve the scaling and reliability problems."
A jumble of standards
Compounding these issues is the lack of standards and the proposal of standards that appear to compete or overlap. For example, there are four standards proposed for signaling between routers and optical transmission gear: the Optical Internetworking Forum's User-to-Network Interface (UNI); the Optical Domain Service Interconnect's UNI; Multiprotocol Lambda Switching; and the Automatic Switched Optical Network specification.
"Why four standards and not one? We don't have one language, one currency or one government in the world," McQuillan notes. "But this is a very, very pivotal issue for our industry and we're only at the beginning."