2,500 Cisco access points make it one of largest 11n nets announced
Duke University is the latest school to take the 802.11n wireless LAN plunge. It plans to upgrade the campus network with 2,500 Cisco 11n access points.
Duke University says it will install more than 2,500 802.11n access points from Cisco to create one of the largest wireless LAN so far announced for the draft IEEE standard.
The university will blanket most of its Durham, N.C. campus, some 6 million square feet with Cisco’s Aironet 1250 two-radio access points. The school launched a limited pilot of the 1250 last fall, consistently achieving 130Mbps for 11n clients. Because of the multi-antenna technology (called MIMO) in 11n, even existing 802.11g clients saw a big jump in throughput, almost double their previous data rate when connected to the existing campus WLAN.
Duke has concluded that wireless has become the primary connectivity mode for a fast-growing number of its 45,000 students, faculty and staff. The 802.11n equipment promises much higher throughput for end users, and higher aggregate network capacity. But just as importantly, it also promises a much more reliable and resilient radio signal then existing Wi-Fi networks. (Compare 11n products).
That combination has led at least one analyst to speculate that 11n spells the “end of Ethernet” at least as the principal access network for users.
While some institutions have taken the plunge with 11n, others remain skittish because 11n remains a draft standard that’s not expected to be formally ratified by the IEEE until sometime in 2009. Another potential issue is how to power a dual-radio 11n access point, which can draw twice the wattage supplied by current 802.3af power-over-Ethernet products. Equipment for the higher-wattage 802.3at standard is only slowly coming to market and WLAN vendors have developed an array of work-arounds in the meantime.
The 11n network will let Duke wirelessly deliver demanding multimedia applications, with streaming video and audio and even high-definition TV, to users wherever they are. Many schools see high-throughput wireless networks as a way to support highly collaborative interactions among students and with faculty across the entire campus at nearly all hours. A dean with Duke’s Pratt School of Engineering, quoted in the independent Duke Chronicle, envisions a pervasive, 11n WLAN changing the space-time continuum: enabling students to create distributed design teams with engineers in China or India, spanning many time zones.
Duke currently has just eight Cisco 1250 access points deployed, from the original pilot network. The university IT group is now receiving and installing another 200. The remaining 2,200-odd devices will be installed over the next six to nine months, says Kevin Miller, assistant director, Communications Infrastructure, with Duke’s Office of Information Technology.
The network design is aimed at supporting several operational scenarios or “use cases.” At one end, says Miller, is scenario that calls for delivering roughly 25Mbps throughput for each of five to six clients in close proximity. At the other end, is 2Mbps each for a larger group of 25 to 30 users. “Testing has indicated that we can support these use cases with the 802.11n network,” Miller says.
Initially, some access points will be powered via switches that support the existing 802.3af standard. But access points in areas with the greatest client density and throughput requirements will be powered via Cisco 3750-E switches with what Cisco calls “enhanced PoE,” announced just last month. Enhanced PoE is Cisco’s own extension to the 802.3af standard, boosting power to as much as 20 watts from 15.4 watts per port. It’s an interim step until the final ratification of the 802.3at standard.
Duke is the latest in a string of 11n deployments in higher education, many of them campus-wide and consequently with hundreds of 11n access points. The first was Morrisville State College, Morrisville, N.Y., which has deployed more than 700 11n access points from Meru Networks. Wireless pioneer Carnegie Mellon University in December selected two WLAN vendors, Aruba and Xirrus, as its 11n suppliers for a phased WLAN upgrade that may in the end exceed Duke’s: CMU estimates it might end up with about 3.000 11n access points.
A much smaller Cisco deployment was just announced for Concordia University in Montreal, Quebec. Like Duke, Concordia is a Cisco network shop, and it plans to gradually upgrade its existing 802.11abg wireless LAN to 11n. It plans to start first with campus areas that have lots of users and high traffic, says Andrew McAuslan, associate vice president for instructional and information technology services at the university. “There’s a larger data pipe with 11n, so it can serve more simultaneous connections,” he says. “And 11n delivers video that’s noticeably better [than video over 11abg networks].”
Concordia plans to start with about 24 11n access points, and then replace another 120 to 140 existing access points over the next 18 months. The school actually has two campuses in the city, about 1 kilometer apart. Outside on both campuses, Concordia is deploying Cisco Wi-Fi mesh nodes, and in summer of 2008 plans to wirelessly link the two sites with still more mesh access points.
The University of California at Berkeley has a Cisco 11n pilot network operational to evaluate the performance.
