Gig-E goes to the head of the class - Packet Engines and Avista, Gigabit Ethernet for Spokane, WA, schools' metropolitan area networks - Company Business and Marketing

Communications News, Feb, 1999 by Brian McCleod, Jim Sr. Burke

The Spokane municipal school district runs Gigabit Ethernet over dark fiber for high-speed local and metropolitan area connectivity.

Until recently, metropolitan area networks (MANs) were thought to be the domain of traditional telecommunications technology such as T1, T3, synchronous optical network (SONET), or asynchronous transfer mode (ATM). Today, newly standardized Gigabit Ethernet has emerged as a viable alternative. It bypasses the protocol conversions required to traverse carrier networks and avoids the technical complexity of ATM.

Packet Engines, a provider of gigabit networking solutions, and Avista Corp., a subsidiary of Washington Water Power, are providing the technology foundation for an educational project that represents the first major application of extended-distance Gigabit Ethernet technology into an integrated services MAN.

The Educational Metropolitan Area Network (E-MAN) will connect Spokane-area K-12 school districts, community colleges, and universities in a bid to link 120 educational sites over the next two years. District 81, the largest school district in the city of Spokane, is the first educational agency in Spokane to begin deployment, providing students and teachers with access to the E-MAN.

The project evolved as it became apparent that existing school networks desperately needed upgrades to increase bandwidth capacity and expand computing capabilities. The school systems needed a solution that would deliver high-speed, high-capacity connectivity while simultaneously reducing long-term recurring costs.

Several educational agencies came together along with the TMC Group, a Seattle-based consultancy, to form the E-MAN consortium that would define requirements, develop a network configuration, and issue a request for proposal (RFP) to vendors providing the network infrastructure. The educational agencies placed a premium on a standard, flexible, and reliable solution that would have a life span of approximately 10 years.

Responses to the RFP came in from leading networking equipment and fiber utility vendors. Once the scope of the project was understood, it was apparent from a fiber perspective that Avista Corp. had the most experience in outside fiber plant deployment and maintenance. On the networking side, leading industry vendors submitted solutions ranging from ATM to SONET to Gigabit Ethernet for the backbone of the E-MAN network.

VIABLE SOLUTIONS

ATM and SONET technologies were valid options to consider, since MANs traditionally rely on telecommunications carriers for connectivity. However, both ATM and SONET threatened to add to network cost and complexity. Since most desktop equipment depends on Ethernet connectivity, deploying other technologies for the MAN would demand additional network integration overhead, such as training personnel on multiple technologies and providing equipment to translate from Ethernet to other technologies and back again,

In addition, ATM would involve greater costs, since the fiber plant design specified a ring configuration for maximum resiliency. Networks with ATM at the core and Ethernet at the edge are typically deployed in a star configuration. In the case of E-MAN, if ATM is implemented in a ring configuration, the network then requires an ATM switch at each site, substantially adding to capital equipment costs--something the E-MAN consortium was trying to avoid.

The E-MAN consortium predicts annual traffic on the network will grow up to 40% each year, and Gigabit Ethernet technology promises enough capacity to accommodate this usage. Most end-user connections will run at 10 or 100 Mbps, with some high-speed servers directly connected to the Gigabit infrastructure.

The lower-speed ports on the routing switches are all 10/100 capable, so the backbone infrastructure can cope with increases at the desktop without upgrades. The per-port cost of implementing Gigabit Ethernet is already lower than ATM or SONET, and increasing volumes of Gigabit Ethernet shipments will drop prices faster than with these comparable technologies. Gigabit Ethernet offers higher bandwidth and a more flexible infrastructure, which translates to longer life as network traffic grows over time.

In addition, the E-MAN RFP specifically calls for voice over Internet protocol (VoIP) as the desired videoconferencing application for the schools. Most peripheral developments in videoconferencing like VoIP are targeted at mainstream equipment typically connected via Ethernet. The marriage of Gigabit Ethernet with Gigabit Ethernet routing switch technology provides the benefits of routing everywhere without any performance penalty. And the addition of quality of service (QoS) provides the appropriate protection for time-sensitive voice and video traffic.

DARK FIBER CONNECTIVITY

The E-MAN design spans 65 route miles of backbone fiber, with an additional 105 route miles of distribution fiber to complete the project. For a high degree of resiliency, the design requires four fibers to be installed at each school facility in a ring configuration to transport the Gigabit Ethernet networking traffic.