Gig-E goes to the head of the class.
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.
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.
To design and build a network of this magnitude efficiently and economically, the fiber engineering team created a custom tool set that includes a database with a graphical user interface (GUI) and Geographical Information System (GIS) links. The custom tool set not only helps track progress, but also allows each circuit to be designed, routed, and fused logically before a single physical termination is made. The result is significantly improved efficiency and lower implementation costs. All fibers are fused at each cross-connect point, providing the low decibel losses required by long-distance gigabit transport. For example, 112,000 feet of fiber connection with 20 splices has a small 11-decibel loss.
This dark-fiber-leasing package provides E-MAN with the best of both worlds--a private interconnected MAN topology with essentially unlimited bandwidth, plus the bonus of maintenance and repair expertise from a local utility company. This is a departure from traditional solutions provided by legacy systems where all traffic is aggregated at central points and transported together with other client traffic. Leasing the fiber ensures E-MAN security and privacy, as well as the flexibility of using non-traditional transport mechanisms such as gigabit technology.
THE RESULTING SOLUTION
After an extensive evaluation by the E-MAN consortium, it was clear that Gigabit Ethernet, provided by Packet Engines, was the best choice for a scalable and reliable high-performance networking solution that was also the easiest to manage. Avista Corp. dark-fiber service offering made practical and economical sense, providing the schools with a reliable, fiber-optic cable foundation enabling transparent end-to-end connectivity at costs similar to their legacy systems already in place.
The E-MAN network application demonstrates that a full range of integrated services can be deployed with high quality across an Ethernet MAN over dark fiber. The combination of Gigabit Ethernet and fiber provides a highly reliable and scalable network solution that will allow E-MAN to meet bandwidth demands without having to replace equipment, even as usage increases, into the next millennium. Ultimately, the students will reap the benefits of connectivity provided by the E-MAN, enabling them to access a wealth of information and bringing a new level of advanced teaching methods to participating school systems.
McCleod is director of marketing for Packet Engines, Spokane, Wash. Burke is senior telecom engineer at Avista Corp., Spokane, Wash.
Circle 251 for more information from Packet Engines
Circle 272 for more information from Avista Corp.
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|Title Annotation:||Company Business and Marketing; Packet Engines and Avista, Gigabit Ethernet for Spokane, WA, schools' metropolitan area networks|
|Author:||McCleod, Brian; Burke, Jim Sr.|
|Date:||Feb 1, 1999|
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