Friday | 10 July, 2009
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First large-scale 802.11n wireless LAN now operational
Morrisville State College has 720 access points that create a pervasive, reliable, high-throughput wireless LAN
John Cox (Network World) 30/11/2007 08:23:14

The world's first large-scale 802.11n wireless LAN is now operational. And students using the network at the small, rural New York state college where the wireless technology is deployed say they see a dramatic difference in what they can do with it, along with a more reliable WLAN connection.

The 11n WLAN, based on gear from Meru Networks, is still in its shakedown phase, according to Morrisville State College IT staff. The 720 new AP 320 11n access points, hot off Meru's assembly line, replace the same number of 11a/b/g access points installed over the summer in the first phase of Morrisville's migration to 11n.

There's been no time yet for systematic performance and capacity testing, but students and IT staff say they're seeing improvements compared to the previous 11a/b/g infrastructure. Bandwidth-hungry applications are noticeably faster. Classrooms can run video newsfeeds and online conferences without buffering delays. Users don't have to struggle with dropped connections.

MSC student Timothy Koch, a senior in the Network Administration bachelor's degree program, says 11n throughput and capacity are changing what can be done in classrooms. In his Network Defense and Countermeasures class, for example, students now can work effortlessly with streaming video feeds and online security conferences. "The wireless [network] that was provided before wasn't fast enough to watch the video feeds," Koch says. "The videos would still take time to buffer, and it was annoying when you're trying to participate in class exercises and the video streams do not want to function properly."

Currently, Morrisville is seeing just over 1,200 simultaneous wireless clients at peak periods. There are about 3,000 official, registered users. Besides laptops there are about 80 other devices on the network to date, including new wireless iPod Touches, a few Apple iPhones, some other handhelds and wireless gaming consoles.

Meru was the first vendor to ship Draft 2-compliant 11n gear, but its rivals are crowding close behind. Colleges and universities are among the first organizations to take the plunge with 11n. Duke University is piloting Cisco 11n access points at several dorms, and Carnegie Mellon University has announced its decision to deploy 11n gear from Aruba Networks and Xirrus in 2008, in a massive, campuswide WLAN.

The advent of Draft 11n equipment could mean the "end of Ethernet" as the medium for client access, says Burton Group analyst Paul DeBeasi. One reason for the willingness to adopt the new equipment is the 11n interoperability testing now under way by the Wi-Fi Alliance.

Still unresolved: Power over Ethernet

One major issue still unresolved is whether to upgrade the campus to the higher-wattage Power-over-Ethernet standard, 802.3at, sometimes called PoEPlus. The WLAN vendors are handling this in different ways. Currently, 90% of the Meru access points are using the campus' existing 15-watt 802.3af-based PoE infrastructure, drawing power through the Gigabit Ethernet ports of Enterasys Networks LAN switches.

This limits the access points to what's called a 2x2 antenna configuration, which breaks a data stream into two substreams for transmitting and receiving. To run both radios at the same time in a 3x3 antenna configuration, which Meru supports, requires higher wattage, however. According to Meru, there is no difference in data rate and throughput. The difference is in the reliability of the signal: The more streams there are, the more reliable is the signal. And the 3x3 arrangement will support more clients on each access point, the vendor says.

PoE gear based on the 30-watt 802.3at standard is only just starting to become available. MSC is testing an 802.3at power injector from Phihong to see what impact the third pair of antennas will have, says Matt Barber, MSC's network administrator. The performance question is complicated by the fact that all existing 11n clients have only a 2x2 antenna arrangement, says Jean Boland, MSC's vice president of information services. They'll be testing the 3x3 AP configuration with several embedded and plug-in 2x2 11n client radios.

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