Optical in the enterprise

Once the sole purview of carriers, beaming gigabits over glass is now taking root in corporate networks.

Optical switching and transport systems are finding their way into corporate networks as users deploy fiber to support high-speed connections and bandwidth-hungry applications between buildings in a metropolitan campus. Educational institutions and governmental bodies are leading the way; even a few utilities and financial institutions are seeing the light.

Chief motivators for employing light instead of electrons are simple physics and economics: moving more weight - in this case, applications - at faster speeds, leading to operational efficiencies that save and make money.

The state of Hawaii, for example, is deploying an optical Ethernet network to support increasing amounts of bursty data traffic and cap its investment in SONET.

Hawaii's Institutional Network (INET), which connects the state government, Department of Education and the University of Hawaii and its community colleges, has an optical Ethernet network augmenting an OC-12 SONET ring. INET is installing up to 30 Luxn WavSystem wavelength division multiplexers (WDM) to extend its data network.

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Chief motivators for employing light instead of electrons are simple physics and economics: moving more weight - in this case, applications - at faster speeds, leading to operational efficiencies that save and make money.

The state of Hawaii, for example, is deploying an optical Ethernet network to support increasing amounts of bursty data traffic and cap its investment in SONET.

Hawaii's Institutional Network (INET), which connects the state government, Department of Education and the University of Hawaii and its community colleges, has an optical Ethernet network augmenting an OC-12 SONET ring. INET is installing up to 30 Luxn WavSystem wavelength division multiplexers (WDM) to extend its data network.

The network is on the island of Oahu, and is being expanded to Maui and Hawaii.

INET required WDM for its flexibility and bandwidth capacity as it extends its network to outlying areas. SONET proved unwieldy for handling increasing loads of data traffic from Ethernet and Gigabit Ethernet switches at the INET's three users.

"We looked at upgrading SONET and basically felt that it was not cost-effective, and it wasn't going to take us far enough into the future," says David Lassner, technology director at the University of Hawaii. "We could have done a moderate increase in capacity but then we would have been pushing the envelope on SONET speeds."

Lassner says the alternative to the INET WDM network would have been OC-48 SONET, which would have cost at least five times what Hawaii spent on INET.

The INET backbone consists of two physical rings. The rings are tied together at the Hawaii Community College campus using a Fujitsu SONET switch and a Cisco Layer 3 switch.

INET considered upgrading this network to OC-48 SONET to handle increasing traffic loads, but that would have involved replacing the SONET add-drop multiplexers at each site. Also, the three users of the SONET ring had different bandwidth requirements. Independently allocating, regulating and expanding the network capacity would be difficult in the shared SONET ring because all three users would have to agree on any change.

"It's a shared network, and we have different policies on how we deploy TCP/IP," Lassner says. "Doing a shared TCP/IP probably wasn't going to work, in addition to not giving us enough bandwidth. Our routing issues would have been just too complex."

Each user also had different voice and data requirements ranging from T-1 to 10/100M bit/sec and Gigabit Ethernet. While T-1 service is easily mapped into SONET, the various data services would require SONET framing and the inherent overhead and bandwidth inefficiencies.