Microwave gives schools a textbook solution; security and future proofing were major considerations in the final selection - Wireless

Communications News, June, 2002

How do you bring connectivity to 23,000 students--K-12, and adult education--in an area 10 miles by 21 miles with 28 campuses? This daunting task faced the Palm Springs Unified School District in California. It needed to connect all of the campuses in Cathedral City, Desert Hot Springs, Rancho Mirage, Thousand Palms and Palm Springs with the school district office and the service-center facility. Not only did the district need the connectivity between the sites, but buildings and classrooms also needed to be wired to bring the intranet and Internet to the students and faculty--with a minimal amount of IT staff to oversee it.

The school district looked at all options that provide connectivity with a reasonable return on investment (ROI), and that allowed for expansion without having to re-do the whole infrastructure as growth dictated.

According to Ben Curatolo, director of technical services, "Being a public school, you only have one shot to do it right, and that means using long-range vision of where you want to be 10 years from now. You need to build your technology as much for the future as for today."

Staff looked at spread spectrum, microwave radio technology, dial-up modems, wireless modems, leased lines, and dark fiber from various utilities, as well as cable and ATM. The solution that proved to work the best with guaranteed throughput, good ROI, and with the easiest expansion and upgrade path was microwave radio technology from Airlinks Networking, Ft. Wayne, IN.

The topology consisted of three main cluster sites with everything ending back at the district office. Every cluster site would have between three to 10 campuses coming into it, and that cluster would go directly to the district office. The schools coming into the cluster sites would all be dual 10-Mbps radios, and the cluster sites to the district office would be comprised of 45-Mbps DS3 radios. The dual radios would add the reliability of a backup system and additional bandwidth by using load-balancing routers.

NOT WITHOUT PROBLEMS

According to Dave Isbell, director of administrative technology, "The project was stalled a few times, because the original project management company was bought and sold twice after the start of the project--something no one could have predicted."

Isbell also mentions a few other delays that no one expected, such as, "having to coordinate everything with four cities, Native American agencies, and `quirky' county and state of California laws." Even internal communications sometimes never made it down the chain to the right parties.

"In one instance, right after a link was put up and running, it started to fade in and out, and finally, after a day, went out completely. Turns out that a two-story mobile classroom building was being put up right in the middle of the path and blocked the line of sight for that link. The situation was resolved quickly, but it still added a few anxious moments. Since then, our interdepartmental communications have greatly improved."

One of the ways security on the network is handled is by running virtual LANs through the district's Cisco-equipped backbone. Alex Garcia, WAN manager for the school district, explains, "Security is an important part of the WAN and LAN. Because of the sensitive information contained in the student information data, we needed to be sure we could secure everything.

"One of our goals in establishing the wireless WAN was to be able to collapse some of the network resources and bring all of the enterprise class servers back to the district office," he adds. "This would enable us to manage the network more efficiently with a small staff. If a problem arose with a server, we didn't have to travel to one of the school sites to resolve the issue."

Isbell adds, "We wanted absolute assurance that the network from the unified district office to the wall plate in each classroom was valid and functional. From the district office, we wanted to be able to check the validity and integrity of the entire system. All connections were to be in the wiring closet of each school, with home runs only from one device/jack to the closet switch. Classroom and/or office hubs/switches or cross connects were not allowed. We wanted to eliminate as much of the time-consuming part of network troubleshooting as possible--such as bad wiring and unauthorized changes."

NEW APPLICATIONS POSSIBLE

"Most classrooms have a minimum of eight drops," explains Curatolo. "Each site has a gigabit backbone with 10/100 Mbps to the desktop. With the way the infrastructure has been set up, the school district is ready to step up to video-conferencing, voice over Internet protocol and video streaming."

A major consideration in the project was how well the radios and components would stand up to and function in the harsh desert environment. Everything from the outdoor units of the microwave radios, to the cabling, tie-downs and indoor equipment closets had to be considered. Hundred degree-plus temperatures for almost five months of the year can shorten the life expectancy of any equipment if not planned out properly. "So far," according to Garcia, "we have had very few failures of any kind. But it does mean keeping a vigilant watch on the air-conditioning units, which keep the equipment cool."