Case Study

Dense 802.11n Network Supports Mobile Devices on USD Campus

• By Bridget McCrea
• 03/12/09

With 12 controllers and nearly 1,500 access points dotted across its 180-acre campus, the University of San Diego's 802.11n and a/b/g wireless network just might be one of the densest in the country. Coverage certainly isn't lacking anywhere on the sunny urban campus, where distinctive Spanish-style buildings with red clay roof tiles dot the hilltop university just outside downtown San Diego.

According to both Vice Provost and CIO Christopher Wessells and Director of Networking and Telecommunications Douglas Burke, coverage on the USD campus is about as ubiquitous as wireless can be. "We wanted the user experience to be amazing," Burke said. "It's definitely pervasive coverage. We've received a lot of compliments about it."

USD's entire wireless network is composed of controllers and access points from Aruba Networks. The reliability and innovation of Aruba's technology has been a principal factor in their decision to deploy Aruba gear, Wessels said. At the same time, both administrators stressed the importance of a solid wired network behind the WiFi and said that the realities of wireless technology dictate a constant three-year upgrade plan to keep a wireless network current.

The university's 7,832 students, including 1,120 in its law school, can access the wireless network from virtually everywhere, including the law library, main library, business school, and student union. Coverage includes all classrooms, where the dense wireless network helps ensure that law students can use their laptop computers along with specialized software called ExamSoft to take exams. Virtually all law students at USD have wireless-enabled laptops, and the law school's needs were some of the drivers behind the move to the new 802.11n standard in January 2008, Burke said. "Our law school was one of our biggest consumers of wireless. They needed something faster and better than a/b/g."

A number of products are already available for the new 802.11n standard, which hasn't yet garnered final approval from the IEEE committee in charge of wireless standards. The 802.11n standard significantly improves data transfer rates over the earlier wireless standards in use at most colleges and universities--usually 802.11a, b, or g, or a combination of the three. Final approval of 802.11n is expected in mid-2010.

The USD wireless network uses Aruba controllers and access points, with 12 Aruba controllers and 1,428 access points, 972 of them 802.11n. The remaining APs are a/b/g.

While one of the advantages of the new standard is that it is much faster, one of the challenges of moving to 802.11n, Wessells and Burke pointed out, is that a denser deployment is usually needed. That's because of 802.11n's higher frequency, which does not penetrate walls as well as a/b/g. For example, upgrading the residence halls from a/b/g to 802.11n will require an additional 1,000 access points in order to ensure the same high level of coverage, Burke and Wessells said. For cost reasons during the recession, the university is delaying the residence hall upgrade to 802.11n for the time being.

On the other hand, that same high-frequency characteristic makes the 802.11n standard a better solution for large classrooms, Burke said, because the 802.11n frequency "tends to reflect rather than pass through walls."

At USD's business school in particular, the importance of being known for having solid wireless coverage "has been huge," Wessells said. Business Week magazine recently released its annual ranking of the best undergraduate business schools, and USD has moved up to twenty-ninth in the national rankings. "We don't know all the variables that go into the rankings, but we like to think that great n wireless coverage may have contributed to that improvement," Wessells said. He mentioned a recent informal conversation with a student who surprised him by specifically complimenting the university on its excellent wireless coverage.

The Wired Backbone
But the super-saturated wireless network doesn't mean USD's wired network is going away any time soon. To the contrary; Wessells and Burke described their Cisco wired network as essential to the university's overall high-quality network and said they plan to keep it that way. "Wired is still the backbone of our network," Wessells said. "Administrators ask me periodically if we still need it. My answer is, 'Absolutely yes.'"

The performance of the wired network is critical to the speed of the wireless one, Burke pointed out, since all wireless access points are connected back to wired Cisco switches in a closet somewhere on campus. "You clearly need great technology there as well," he said, although he also indicated he expects to see fewer and fewer people plugging in to the wired network; new buildings will reflect that reality with fewer wired ports. Residence hall students, for example, use the wired network very little in the dorms. "Students are smart: They know to use wired when they need more speed," Burke said. "Wired will always be faster than wireless."

Innovation and Change
Another challenge with wireless is keeping up with the unrelenting drumbeat of innovation and change. USD has a strategy to replace its wireless network every three years, Wessells said, and added that he finds that pace an essential part of the wireless equation. "We believe that universities in general need to think about innovative ways to fund the replacement of wireless on a three-year cycle," he added.

Another unknown that both administrators mentioned is the impact as more and more students jump on the WiFi network with wireless-enabled devices like smart phones. "It's a bit of a surprise," Wessells said. "The impact is still unclear."

USD is also open to new ways to use the wireless network for less conventional applications and services. For example, mindful of its location in the water-starved West, the university is working with irrigation system manufacturer Rain Bird Corp., Aruba, and the USD facilities department to develop a sophisticated sprinkler control system that runs on the university's wireless network.