With the dramatic increase in traffic on the wireless network, users enjoy broadband wireless access at the same time, for effective and robust quality of service and the demand for more and more prominent. QoS implementation of the first applications to accurately distinguish the type of each network, followed by distribution to appropriate network resources, such as bandwidth and the relative priority and so on. Early research focused on the wired network QoS, provided above the network layer quality of service guarantee. Such as the Integrated Services / resource reservation, DiffServ, MPLS, traffic engineering, constraint routing, subnet bandwidth management, etc. [3]. But the above QoS mechanism can not be directly applied to wireless networks, there are two reasons: First, different wireless transmission and wired transmission, wireless transmission, crosstalk and multi-path propagation causes fading and dispersion, so the wireless network has data transmission rate and bit error rate characteristics; the WLAN and WPAN etc. To ensure flexibility and compatibility, protocol standards generally develop MAC layer and PHY layer specification, resulting in network and wireless link QoS upper layer separation end QoS can not be brought into full play; Second, with the wireless access technology, the application of heterogeneous networks will become increasingly popular, a variety of applications usually through wireless access, wired backbone network transmission, the transmission of wireless access way, in this case, closely rely on the traditional wired network QoS mechanisms have been unable to provide end to end quality of service and the urgent need for a wireless channel to the characteristics of the wireless link layer Media Access Control sub-layer provides the network the distinction between business, priority control, resource allocation, etc. QoS control and security, so that the wireless network and wired network QoS for the overall planning. This article will examine the two wireless networks to provide QoS guaranteed media access control protocol - May 2002 published IEEE802.11e D3 [4] and in February 2003 announced the IEEE802.15.3 D16 [5], the first of two MAC media access protocol mechanism, followed by the comparison of the two protocols in handling multiple data service types, different network configurations to address the "hidden node" problem and other aspects of the advantages and disadvantages, and finally give conclusions.
Birmingham City Councils attitude is not so clear. When asked whether the test result of deploying Linux PC from Microsoft, got more favorable conditions, the Birmingham City Councils IT director, said Green, we did not try to get special offers from Microsoft, this is not our Linux project objectives. But he did not clearly indicate whether Microsoft has provided access to special offers. Many observers have pointed out that once the regional government showed interest in open source, Microsoft will be offering special concessions to ensure that they continue to use Windows. Laurent, senior analyst at Ovum, said Microsoft will be desperate to lower prices to get the deal. If Microsoft will reduce the price of deploying open source software to lose their meaning when, for the customers is a good deal.