"This was devastating to the productivity of some work areas," says Bret Thomas, computer hardware specialist for Memphis Light, Gas & Water, which is the largest three-service public utility provider in the United States.

The bandwidth-heavy work-management and GIS applications, along with a new CIS (customer information system) under development, were the driving forces behind the utility's decision to build a MAN (metropolitan area network) connecting its service centers and community offices to the data center. Now Memphis Light, Gas & Water is finishing up a massive network makeover to its new Gigabit Ethernet MAN with frame relay backup. Currently, the gigabit pipe runs mostly through the MAN architecture, but hefty applications such as the utility's work-management system will get gigabit NIC cards for their servers. "When we finish the network upgrade in the third quarter, we will baseline our applications. If we find bottlenecks at the server level, we will push gigabit NICs as needed," Thomas says.

Thomas says the utility decided against an ATM MAN because it is more complicated and expensive, and it requires more equipment. A third-party integrator, Venture Technologies, Ridgeland, Miss., spearheaded the design and installation of the network, which primarily uses existing fiber. At the heart of the MAN are two Cisco Systems Catalyst 6509 switches with a redundant eight-gigabit EtherChannel link.

Like most organizations that go gigabit, the utility is nowhere near tapping out the pipe; it currently uses less than 5 percent of its capacity. Still, it has the ability to upgrade to 16 Gbps with EtherChannel, Thomas says. Memphis Light, Gas & Water's network doesn't suffer the distance problems with cabling that some Gigabit Ethernet networks experience. The utility's longest link between wiring closets is 34.3 km, which is well below the 75-km extension of Cisco's 1000 ZX technology.

Each location is configured as its own VLAN (virtual LAN) to isolate Layer 2 broadcasts. "We are keeping that traffic off the gigabit loop," Thomas says. The only catch is that the current version of the utility's CiscoWorks application, which it uses to manage its switches and remotely configure the VLANs, is not Web-enabled. If the application were Web-enabled, the IT staff could access it simultaneously, locally or remotely from home via the Internet/VPN. "Now, you have to be in the computer room to see the status alarms and do the configurations from the console," Thomas says.