Lesson 181: IEEE 802.11a and 802.11g Wireless LANs

摘要

IEEE 802.11b is arguably the most successful networking technology of the early twenty-first century. It has moved the Wireless LAN (WLAN) from niche to mainstream. It's popular within enterprises and for remote access in hotspots. However, both its data rate and the radio spectrum it uses are limited: Even under ideal conditions, most users only see a small fraction of its advertised 11Mbit/sec data rate, and interference usually reduces this even further. To improve WLAN performance, the Wi-Fi Alliance (www.wi-fi.org) has adopted two other IEEE standards: 802.113 and 802.11g. The former has existed on paper since 1999, but real products only became available in volume in 2002. The latter was ratified in June 2003, with the first officially compliant hardware due to ship in August 2003.