ANALYTICAL TESTING FOR IEEE802.11b

With the modern implementation of new standards for high-rate wireless LANs (WLANs), mobile users are promised the levels of performance, throughput, security and availability equivalent to those of traditional wired Ethernet. As a result, WLANs could be on the brink of becoming a conventional connectivity solution for a broad range of business and home users. If WLAN’s are to replace or compliment the traditional wired LANs, a significant question is how and to what extent wireless technologies can handle data traffic differently from wired technologies. Issues such as bandwidth, effective throughput, security, range and reliability will decide on the future of a wireless LAN. However, Ethernet technology has evolved and matured over a long time period and it is regarded as the most popular LAN technology in use today. Ethernet is admired because it strikes a good balance between speed, cost and ease of installation. Business and home users are reluctant to migrate from their existing, wired LANs because they are confused over the abilities of wireless equivalent. This project thoroughly investigated current WLAN technologies in an effort to shed some light on their current abilities and their potential for becoming a mainstream connectivity solution. In particular, the investigation concentrates on IEEE 802.11b standard and its equivalent counterpart the 10Mbps Ethernet. Both of these technologies are not currently the best available in there own categories. However, enhanced versions of those technologies work in a fundamentally same manner. Therefore, any conclusions made in this report can be applied to other respective standards. Initially the report presented all necessary information regarding fundamental networking concepts which apply to both technologies followed by a detailed investigation of the standards themselves. This was followed by a substantial number of previously designed experiments which were based on the findings from initial investigation of the two technologies. The extent of the experimentation went way beyond many currently available research papers on the same topic. Te results indicated some major issues with 802.11b standard as well as some fundamental differences between two technologies. Although there have been significant developments in wireless technology with a maximum air rate of 11Mbps available for 802.11b products, the wireless overheads are still large and this still limits the throughput. The overall throughput for the wireless systems that have been tested is ~40% of the maximum air rate and therefore figures of 4.7Mbps are obtainable. These figures are approximately the maximum figures that can be obtained, but the overall throughput may be lower depending on the environment the system is operating in, and the number of people using the network at one time. At the same time, Ethernet has performed significantly better. Maximum throughput obtainable was 90% of the maximum bit rate and figures of 8.9Mbps were easily achievable. However, instability outside the preferred operating regime is not unique to WLANs. In many cases Ethernet’s performance degraded as circumstances changed. At the end of the experiments, a move to 802.11b from an existing wired network is not recommended unless there us an overwhelming need to do so. The IEEE802.11b WLAN has its places, and in those places it performs well. Furthermore, it should be considered as part of a hybrid solution due to deployment advantages and the mobility it provides to users. Future wireless technologies will no doubt improve, but the limitations of a shared medium and reduction in throughput with range will still need to be taken into consideration. Miro Rajic BEng (Hons) CNDS, 2003 4