This is one of the 25 access points that provided the wireless connectivity for the event. The access points — Cisco Aironet 1250s — are based on the latest wireless LAN specification, 802.11n, and Cisco is keen to showcase them.
802.11n is not yet a standard — standardisation may not happen until next year. But it has many benefits, including a theoretical throughput of 300Mbps — more than five times that of the previous WLAN technology, 802.11g — and greater range, between 50-100 percent more than 802.11g. It also utilises some new techniques for assembling multiple data streams and avoiding interference.
Even with those benefits it was never going to be easy coping with a large volume of concurrent users, which rose to 635 during one interval — but the network appeared to hold up well. The network was being analysed by the PC shown in the photo, which was running Spectrum Expert from Cognio, a company that Cisco bought in September 2007.
But although the network was based on 802.11n, most delegates were using 802.11g, or its predecessor 802.11b, meaning the data rates they were experiencing would have been far lower.
Actual data rates in WLANs are typically around 20 percent of the theoretical data rates, although that depends on how far the user is from the access points, levels of interference and how well the radio signal propogates.
Inbar Lasser-Raab, senior marketing director in Cisco's access routing and switching division, admitted that demand for 802.11n was currently low, but increasing. She justified Cisco's early release of the 802.11n access point by saying that there couldn't be demand without companies first providing the equipment.
"We are seeing interest, definitely — it's starting. But it's like chicken and egg," she said.
