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 Fiber, Gigabit Ethernet Make the Spokane MAN January 25, 1999 | |||||||||||||||
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By Kelly Jackson Higgins Sometimes it takes a village to build a MAN. Such was the case in Spokane, Wash., where the construction of the new fiber-based Gigabit Ethernet educational metropolitan area network (EMAN) for K-12 schools and state universities is under way. The first to join EMAN is Spokane Public Schools, the state's second-largest school system with 54 buildings and 32,000 students. After Spokane-area voters passed a bond initiative last year to upgrade the school system's voice and data infrastructure, local officials selected the fiber MAN ring network and decided to lease dark fiber from a local utility and run Gigabit Ethernet, rather than ATM. Now Spokane officials have begun lighting up that fiber with voice and data traffic from the school system. EMAN could eventually connect all of Spokane's 13 educational institutions--about 120 sites overall. Each building within the Spokane Public Schools system has or will have a fiber connection, as well as 10/100 switched Ethernet to the classroom. "We can put a telephone or computer in each outlet on the wall," says Dennis Schweikhardt, manager of technology infrastructure for Spokane Public Schools. Spokane went with this universal wiring scheme to support telephones and video to the classroom, as well as faster Internet access. "Instead of running our old frame relay circuit, we have a gigabit fiber line [to the building] and 10/100 switched to all classrooms," Schweikhardt says. Spokane officials chose to lease the dark-fiber ring because it gives them unlimited access, and a pay-as-you-go setup. "We attempted to plan a MAN based on cable years earlier, and there were difficulties over access to the bandwidth and the management of it," Schweikhardt says. "This time we wanted to make it dark fiber, so one agency is on a particular fiber ring." That separates a community college from a public school, for instance, for administrative and bandwidth reasons. One of the biggest drawbacks of Gigabit Ethernet has been its distance limitation over fiber. But distance hasn't been a hurdle for the EMAN project, which calls for distances of up to 20 kilometers. Packet Engines, maker of the PowerRail switches used in EMAN, tested transmissions over single-mode fiber to about 22 km with no problems. One of the most interesting applications of the MAN is that it blends voice and data over IP and Gigabit Ethernet. Spokane school officials are using NEC PBXes over the MAN instead of their old analog Centrex service. That's where the QoS (Quality of Service) issues with IP and Gigabit Ethernet come in. "We have overbuilt the network substantially," he says. Still, the school system and other educational institutions eventually will rely on features such as the ToS (Type of Service) bit in IP and VLAN (virtual LAN) functions in the PowerRail Layer 3 switches, especially when they start adding video traffic. |
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