DALLAS -- Optical Expo 2006 -- Network bandwidth is "exploding" due to demand from applications such as video and multimedia, which will likely require AT&T Inc. (NYSE: T) to upgrade to a 100-Gbit/s backbone by the end of the decade, according to Simon Zelingher, VP of AT&T Labs .

"We will need 100 Gbit/s by the end of the decade," said Zelingher, who was the keynote speaker at Light Reading's Optical Expo, being held here today and tomorrow.

"Currently we are looking at traffic growth that's explosive," said Zelingher. "The past traffic growth was steady and predictable. Now, not only is traffic is explosive, it's unpredictable. All of a sudden, people had a new set of needs. We need to get accustomed to that situation."

Some of the new network needs include the capability to adapt to a wide variety of services, such as VOIP, video, and online gaming, which require low latency and low amounts of packet loss.

"What we see is a lot of multimedia content," said Zelingher. "This includes P2P [peer-to-peer downloading]. It comes in various forms. One is real-time multimedia traffic. This is just beginning to take off. We are going to see a lot more of that."

Zelingher said the rapid adoption of broadband access is pushing the needs of the core network. AT&T has rapidly moved to one global OC-768 (40 Gbit/s) core, but that bandwidth is being eaten up more quickly than expected, he said.

To show how fast the new core, deployed only in the last year, is filling up, Zelingher noted that a 40-Gbit/s DWDM system in one point of presence, capable of carrying 80 wavelengths at full capacity, is already 25 percent full.

Zelingher gave no specifics on AT&T's network equipment, but the company previously announced a contract to buy optical core long-haul gear from Siemens AG (NYSE: SI; Frankfurt: SIE) and switching gear from Ciena Corp. (NYSE: CIEN). (See AT&T Readies 40-Gig Backbone.)

The AT&T network is carrying 5.4 petabytes of traffic every day with 1,600 access points, Zelingher said.

"You can't monkey around with this type of network," he said. "This is the reason why we have to converge the networks. We can't support this kind of scale over multiple networks."

AT&T plans to continue integrating the networks it acquires: first SBC, where integration is still in progress, then BellSouth Corp. (NYSE: BLS) and Cingular Wireless . The last two mergers are expected to be completed later this year.

Zelingher described the single, integrated AT&T backbone as a network that operates in four layers: (1) Hosting centers; (2) IP routers and the "Global Packet Layer," based on MPLS; (3) Intelligent Optical Switching; and (4) Fiber and DWDM. He said this model will be deployed globally.

"Part of the integration is, you have a footprint that is second to none," said Zelingher. "All of this layering has to apply across the entire globe."

Addressing equipment vendors in the audience, Zelingher said service provider optical networking has additional needs, including more standardization that will allow for "plug-and-play" components and better vendor interoperability. He also advised equipment vendors to focus on reliability, especially in software.

— R. Scott Raynovich, Editor in Chief, Light Reading