"This isn't just a network access point -- it's a whole new network infrastructure that holds a lot of potential for new applications. It's been a very exciting project," says MIX architect Susan Campbell, now president of BellSouth Internet Exchange, Atlanta, which runs the NAP. The four BellSouth MIX nodes were strategically distributed around the region in case of severe weather or other problems that could cause outages. A carrier's Internet traffic, for instance, can go through any of the nodes.

IT Department Info Size of MIX IT Department: 15 Campbell's Average Workweek: 80-90 hours Biggest Challenge: Expressing the value of what's been built to customers who are not accustomed to the new technology or architecture, and educating them on this. Latest Projects: Creating new services for Internet exchanges. Coolest Part of the Job: Working with the technology every day and seeing it work.

For now, the MIX is over-engineered with more bandwidth than its ISP and carrier customers can drain, so QoS (Quality of Service) isn't much of an issue except in some cases with multicast. "We're adding bandwidth where customers are experiencing delays [with multicast traffic]," Campbell says. "The network is very reliable for basic rerouting and adding bandwidth. But some of the more complex signaling requirements aren't standardized."

This month or next, BellSouth will activate the MPLS features in its Sycamore Networks optical switches and in its routers, which will let the MIX automatically set parameters for QoS at the IP layer. That will help with multicast traffic, as well as video and voice.

MPLS, which is finally catching on in the carrier space for QoS among different types of networks, will let the BellSouth network support Gigabit Ethernet, SONET, ATM or most any other transport interface, Campbell says. "And it's more scalable because it supports more customers' service types," she adds. It also will help carriers peering at the BellSouth MIX to off-load some IP traffic to keep their backbones from overload, and the MIX network will be able to dynamically adjust the bandwidth based on the QoS parameters. To take advantage of this, carriers must support the Optical Internetworking Forum's UNI (User Network Interface) protocol.

BellSouth's DWDM (Dense Wave Division Multiplexing) architecture is based on Sycamore Networks' SN 8000 DWDM optical network nodes and SN 16000 optical switches in the four Florida locations that house the MIX. Campbell says BellSouth passed on pure ATM, which most NAPs use for transport, because it's limited to OC-12 and comes with the infamous cell tax.

"The other option was adding more fiber, which meant more electronics and regenerators," Campbell says. "DWDM is more dynamic -- it's always on. You don't have to go out and activate new fiber every time you add a new customer."

Provisioning an OC-48 circuit for an ISP or carrier with Sycamore's DWDM software takes only four and a half minutes, versus the traditional days or week it takes with a SONET backbone. "One of the key differentiators is that we can use software for setting QoS, meeting service level agreements and providing dynamic bandwidth and faster provisioning times," says Campbell.