VPNs make waves in the islands - University of Hawaii system - Technology Information

Communications News, August, 2001

Hawaii bandwidth shortage relieved with optical wavelength solution.

To accommodate the growing communications needs of users throughout the Hawaiian Islands, a collaboration emerged among state organizations--the University of Hawaii system (University of Hawaii and Community Colleges), the Hawaii Department of Education (DOE) serving the state's K-12 public schools, and the government offices of the state--to interconnect geographically remote locations with a common communications infrastructure. The mission of Hawaii's Institutional NETwork (INET) initiative is to plan and build cost-effective, scalable networks.

On the main island of Oahu, the initial network was configured with two independent and interconnected fiber-optic backbone rings covering a wide geographic area. These two rings are owned and maintained by this state consortium.

The INET rings used a SONET OC-12 (622 Mbps) on only two fibers provided by Oceanic Cable, Hawaii's cable television provider.

Reallocation of existing bandwidth was difficult because each consortium member would have to agree on changes. Further, new data service requirements, such as Gigabit Ethernet, could not be handled easily by the SONET OC-12 and threatened to consume much of the existing capacity. Additional capacity was required beyond that which OC-12 could support. The question was how to cost-effectively upgrade network capacity and speed when an existing operating infrastructure is already in place.

The consortium decided to investigate solutions that would meet the diverse requirements of each member. While varying in specifics, the general proposals presented to INET by various traditional equipment vendors were to upgrade the OC-12 network to SONET OC-48 (2.48 Gbps). Aside from the expense and time needed to implement this complete system overhaul, two other user needs were not addressed by the SONET solution.

First, upgrading the SONET network would not solve the problem and contention of shared bandwidth. Second, each entity had different voice and data requirements--ranging from T-1 service to 10/100 ethernet to Gigabit Ethernet. While T-1 service is easily mapped into SONET, the various data services would require SONET framing, an inefficient use of the available bandwidth. Two Gigabit Ethernet applications would nearly consume the entire OC-48 bandwidth.

LuxN, Sunnyvale, CA, proposed an entirely different solution, based on the company's physical layer wave division multiplexing capability. By assigning services to different wavelengths, the company provided a high-bandwidth solution that was flexible in nature and that coexisted with the OC-12 SONET network. More importantly, it also allowed modularity in service and bandwidth, so that each of the INET members could manage its own independent private network requirements, while sharing the same fiber pair. As an added benefit, INET's network could be upgraded quickly and without disrupting the existing OC-12 network traffic.

After considering the various proposals, the INET group selected this solution over the more traditional SONET system upgrade. Cost and speed of implementation were key criteria in choosing the solution. This system could be expanded easily by any current node or future location without impacting the existing services of other INET members.

"We wanted an optical networking solution, not a SONET networking solution," says David Lassner, information technology services director at the University of Hawaii. "We now have the capability to manage any of our growth needs incrementally. Of particular interest was the system's accommodation of a variety of traffic protocols. In our view, this will assure easy system expansion and be cost-effective, as well."

This proposal keeps the existing OC-12 SONET network in place, carrying traffic using the 1310 nm wavelength. For new bandwidth requirements, native data traffic is multiplexed onto the ring at various ITU 1550 nm wavelengths. In essence, multiple virtual private networks (VPNs) were created over one pair of fiber.

The basic building block of the solution is the WavStation, which can currently support a variety of traffic types on each of 16 different wavelengths. For the Hawaii INET project, only four of the 16 wavelengths (operating up to gigabit speeds) were required to meet the current needs. Flexibility is built into the system, however, allowing INET to incrementally increase capacity as needed, simply by adding additional wavelengths via a new pair of channel cards.

WavStation supports T-1, 10/100 ethernet, Fibre Channel, SONET OC-3/12/ 48 and Gigabit Ethernet. Because LuxN operates at the Layer 1 level, it can transport these services in their native format at full line speed. No framing of data is required.

The simplicity of this solution is that the department of education, the state government, and the University of Hawaii system can easily manage their own VPNs while sharing the same infrastructure. At any site along the ring, individual wavelengths (service channels) can be added or dropped. This allows complete flexibility in delivering services to any point in the ring, without disrupting other data channels/wavelengths, which are passively sent through the LuxN equipment.