A new path for routing?

Competitors predicted the death of the router, but experts wonder whether it makes more sense to move routing smarts to small devices.

Should routing be done fast and dirty, or smart and elegant?

That's the question facing many network managers, who see the convergence of voice and IP networks, increases in data traffic and new kinds of devices attached to the network as a wave threatening to engulf them. Some want to throw bandwidth at the problem, while others say building routing intelligence into other devices will spread the load and make networks more efficient.

Carl Wood, data communications manager at Tyson Foods Inc., says he hopes to add phone traffic to a network that links more than 200 remote offices to the company's headquarters in Springdale, Ark.

Wood and other experts wonder whether traditional routers and routing schema are the best way to direct new types of network traffic and to give priority to specific types of traffic such as payroll, which should have priority on certain days of the week.

Wood, for example, is considering using the IP routing capabilities built into AT&T Corp.'s frame-relay service to let the service provider handle routing of voice calls over IP. This would mean Tyson wouldn't have to handle voice-over-IP routing in its network infrastructure.

Jerald Murphy, an analyst at Meta Group Inc. in Stamford, Conn., says the debate among internetworking experts centers around whether the ever-increasing load on the routing infrastructure can be best handled by adding smarter routing technologies that can work within the confines of static and sometimes-limited bandwidth. The alternative, he says, would be to expand available bandwidth using optical connections, Gigabit Ethernet or other high-bandwidth links.

More specifically, in a situation where a T1 line running at 1.5M bit/sec. is the fastest pipe connecting sites, routers can be set to classify traffic by IP address, which could, for example, give data between points A and B on the network precedence over traffic between points D and C. However, if the connecting pipe is running over optical fiber at OC-192 speeds, or 10G bit/sec., there may not be a need to prioritize traffic, because the bandwidth is high enough that nothing has to wait.

Close to the User

One scheme to smarten the network comes from Nortel Networks Corp. in Brampton, Ontario. Nortel is promoting OpenIP, a suite of routing development software that it developed and offers to resellers.

OpenIP technology is designed to build routing savvy into any device that has an IP address, by letting it bypass routers and hop on its own from network to network.

Kalai Kalaichelvan, general manager of Nortel's OpenIP division, claims that routers are a bottleneck. He says it makes more sense to put routing intelligence into bunches of small devices that are closer to the user, such as cell phones and personal digital assistants, than it does to make large routers at the outer edge or at the inner core of networks responsible for directing all the traffic.

With OpenIP, according to Kalaichelvan, manufacturers can write code into a device to give it the ability to understand routing algorithms. That allows the device to receive and forward packets over the network without a router.

"It is not the router that is important; it's the routing as a function that's important," Kalaichelvan says. "We have to open this [routing functionality] and have routing intelligence in other devices."

That idea is a little far-fetched, says Charles Boyle, director of research and co-founder of Digex Inc., a managed network and application outsourcer in Beltsville, Md.

"It used to be that you could manipulate routing tables by hand by using all of your tools and service mechanisms to figure out paths," Boyle says. When you work that way, "you have to monitor your network extensively."

However, if Nortel is trying to build the equivalent of routing tables into small devices in a home office, for example, who would be responsible for troubleshooting a PC that does routing when something goes wrong? he asks. "My stereo, [for example], isn't a real good router," Boyle quips.

Tom Russell, director of marketing for high-end routing platforms at Cisco Systems Inc. in San Jose, says he agrees that devices close to the user will eventually become more IP-addressable.

Now network managers are looking for ways to increase routing control and the performance of IP networks by prioritizing traffic, adding security and engineering traffic. The latter, Russell says, refers to predetermining paths through router settings that enable a service provider to send priority traffic over its own network while routing less-critical traffic over the public Internet.

Meta Group's Murphy questions the concept of transferring routing to a variety of small devices not previously endowed with routing intelligence. He says he prefers high-bandwidth optical networks, a category in which he and other analysts say Nortel has focused and is leading.

Too much routing intelligence at the core of a network slows it down, says Alexander Muse, president and CEO of LayerOne Inc., a Dallas integrator that sets up optical network interchanges for service providers.

Muse says that because updating networks to make devices smart is expensive and time-consuming, most routing at the core of the network should be done "dumb and fast" at the optical transport layer, without regard for what types of traffic and protocols are traveling on the wavelengths of light. That leaves it to routers to determine classes of traffic at the network edge.

No one who thinks seriously about high-performance network architectures is happy about putting more intelligence at the core, says Tim Lance, chairman and president of NyserNet Inc., a Syracuse, N.Y.-based not-for-profit internetwork that connects universities and researchers throughout New York. Lance predicts that more intelligence, including routing, will show up at the borders of the network, partially because the applications on the network will have widely varied requirements

What Works?

Tyson's Wood says he's more interested in what works and conserves money and resources than he is in vendor strategies.

Wood says the hub-and-spoke wide-area network works well enough for data that flows between corporate and branch operations. But adding telephone calls over Tyson's network using voice over IP may strain its existing architecture. It would mean calls made from one regional office to another would have to come through routers to Tyson's headquarters, and then go back out through the network to their destination. That, he says, could force him to expand Tyson's core network infrastructure, which means additional capital expenses and increases in ongoing maintenance costs.

Wood says he could avoid those headaches by piping the IP traffic over AT&T's frame-relay network - essentially avoiding the question of how to revamp his routing network by letting the carrier handle it.

The idea of sending IP data packets over frame from one point to another isn't new, but Tim Halpin, product manager for frame and Asynchronous Transfer Mode services at AT&T, says adding IP routing capabilities that facilitate delivery among many locations is.

"Now, instead of just getting packets from one point to another, it's like the network becomes one big router," Wood says.

Diminishing the role of the router by increasing bandwidth or by adding routing intelligence to more devices would no doubt be disconcerting to leading vendors like Cisco, which has the lion's share of the market, according to Jim Slaby, an analyst at Giga Information Group Inc. in Cambridge, Mass.

Although Cisco professes support of open routing standards, Slaby says, "Cisco has really built a bunch of proprietary extensions to existing standards that tend to work only with Cisco products."

Cisco employs a "hybridized" routing scheme, according to experts. The company's scheme combines distance-vector routing and link-state routing. In distance-vector routing, routers regularly send copies of their routing tables to other routers nearby. Link-state routing uses algorithms that help a router compute the best path to a destination on a network.

Among other things, this lessens the need to update sessions, such as a database query or an e-commerce transaction, and gives more bandwidth to applications and less to the routing process itself.

Ultimately, the question of whether colossal bandwidth will obviate smarter routing may become a moot point. As users run more services over internetworks and longer distances, there will no doubt be a need for networks that have speed, capacity and a sense of direction.

Copyright © 2000 IDG Communications, Inc.

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