2 Views: to over-provision or conserve

Talk to Cogent CEO Dave Schaffer for any length of time and the topic of over-provisioning bandwidth is bound to come up. Mention multi-protocol label switching, or MPLS, and you're bound to get an earful.

To Schaffer, the world is awash in bandwidth. So much so that it makes America's overindulgence on oil in previous decades look austere by comparison. But unlike the finite supply of fossil fuel sitting beneath the earth, bandwidth is a reproducible resource so cheap — and getting cheaper — that there is no reason to conserve it.

“We're still only using a fraction of optical bandwidth available in the world,” he said. “To my knowledge, no carrier has lit all of their fiber. We've only literally scratched the surface, and there are a lot more wavelengths left.”

Among the potential methods of managing bandwidth in the network, simply adding more of it is the simplest and most cost-effective way, according to Schaffer. That's not to say that Cogent doesn't consider other methods. The company sees wave division multiplexing (WDM) as a viable way to drive down the cost of transport. It's just not a method the company cares to use often, if at all.

The need to manage bandwidth, regardless of the method, stems largely from carriers' desire to provide different classes of service among customers. MPLS, in fact, caught on in the carrier world in large part because many saw it as a way to offer certain guarantees on IP-based networks that are not inherently able to differentiate between different traffic types.

MPLS, however, has a special place on Schaffer's hit list. Derided as something of a trick created by vendors, MPLS is for those carriers that simply don't have the amount of bandwidth to throw at any problem they see arising, he said.

“What you're doing is taking a Layer 3 port and making it emulate a Layer 2 switch,” he said. “So it's a pretty clever trick by the vendors. It's like saying, ‘Go out and buy a Rolls Royce, and we'll make it emulate a Chevy.”

Such talk is nonsense, though, to carriers and others that say throwing more bandwidth at an issue doesn't necessarily solve the root case of the problem. Schaffer, in fact, stands as something of an anomaly in the industry, where MPLS and WDM of several varieties have become accepted means of managing bandwidth. In fact, MPLS has become virtually a “check list” item for many larger enterprises that won't sign contracts with carriers unless they're using the technology, said Ray Kriss, director of engineering for NetGain, a telecom consultancy.

“For the largest of enterprises, as they go to things like storage area networks and have that kind of preponderance of bandwidth, [MPLS] becomes more important,” he said. “The more sophisticated the end user, the more important it is.”

Because MPLS assigns incoming packets a “label” and sends traffic along label switch paths, many viewed it as the most effective way of bringing carrier-type quality of service (QOS) to an IP environment not designed to differentiate between traffic types. In a network where enterprise users are willing to pay a premium to guaranteed traffic that is sensitive to network issues such as voice and video, MPLS also allows carriers to route around congestion.

“The customer often ask, ‘How do I know that I'm getting top priority,’” said Kriss, who spent 25 years as a sales engineer for Verizon. “Most carriers today can't answer that question. Right now, as more of the carriers are rolling out MPLS, that's when you'll start seeing people not able to hide behind the over-provisioned cloak-and-dagger.”

In the access network, there appears to be little option. Consumers' and businesses' appetite for bandwidth is virtually insatiable. At the same time, because DSL and other broadband technologies typically don't run over shared networks, the ability to manage bandwidth depends largely on increasing the overall amount of capacity.

Currently, most DSL is being offered at 3 Mb/s or less, though there are some notable exceptions such as SureWest's recent move to provide a 6 Mb/s service in the Sacramento, Calif., area. However, as the largest carriers begin implementing their deep-fiber strategies, the requirements are going up dramatically, said Corey Geiger, general manager of OSP broadband solutions for UTStarcom.

“The RBOCs are talking about 50, 60 or 70 Megs now, but there are a lot of moving parts to this,” he said. “When it comes to getting bits to the premises, we know what the options are.”

Among the most recent options is VDSL2, which was approved in May as a standard by the International Telecommunications Union. Beyond providing a way for carriers to offer up to 100 Mb/s over very short loops — and 30 Mb/s over up to 6000 feet of copper — the standard also specifies that carriers offer certain QOS levels. In fact, it's doubtful any technology or standard would develop with such attributes.

“QOS has to be embedded in every service the RBOCs and IOCs bring to market,” said Stephen McCarthy, executive vice president of global customers sales and service for Tellabs.

At the 30 Mb/s level and beyond, carriers should have enough bandwidth to ensure QOS. However, as those levels of broadband are deployed, there will be a certain amount of pressure on aggregation points to provide greater than 1 Gb/s of capacity. That shouldn't be overly difficult for most vendors in the access market right now, though. If telcos are successful in getting significant penetration levels on their highest broadband tiers, bandwidth management as an issue could move from the backbone to the access or aggregation points. The debate currently rests squarely in the network core.

And for the most part, carriers are using MPLS. Equant, for instance, has based much of its network around the technology because enterprise customers want the carrier to provide more than just bandwidth. The company also wants assurance that their applications will receive priority in an increasingly crowded network core.

“The MPLS solution is trying answer some of our customers questions on what we can do at the application level,” said Sylvain Corre, product manager of enterprise application management for the carrier. “More and more customers are challenging the fact that we'd offer more bandwidth to solve the problem. We have to ask, ‘What kind of solution would be easy to implement at the customer site and address the application level as independent as possible from the network. They've experienced in the past that more [bandwidth] didn't solve their problems.” Equant is using both Perrabit and Packeteer equipment as part of its MPLS network. The company views both solutions as a way to provide wide area network optimization while reducing the amount of bandwidth required on the network. Before deploying service to a customer, Equant does a network assessment of the enterprise's needs.

“Most of the time, it doesn't result in increasing the bandwidth,” Corre said. “Sometimes it does demonstrate that the customer needs to increase their bandwidth — but not often. We are very much taking into account the true business need versus the network need.”

Indeed one of the biggest reasons carriers have migrated to MPLS is its ability to ensure performance levels. For Equant, the technology is considered to be a true differentiator. However, it's not the only solution, and sometimes over-provisioning must be considered an option.

“The network is considered more and more of a commodity,” Corre said. “And we are addressing a bundled solution with both techniques because without the network, we can't do anything.”

For Schaffer, the only way to manage bandwidth is to pour it on, and the costs of providing more bandwidth are negligible compared with other techniques.

“Every customer will talk about quality of service, but in the end, the customer cares about the bill at the end of month,” he said. “Certain quality of service is table stakes. Once you've reached a certain point, though, there's not a lot of prestige buying that goes on.”