IEEE 802.11 Standard Suite - cont'd 802.11r Enables fast BSS to BSS (Basic Service Set) transitions for mobile devices, to support delay sensitive services such as VoIP on stations roaming between access points. 802.11s Extending 802.11 MAC to support ESS (Extended Service Set) mesh networking. The 802.11s protocol will enable message delivery over self-configuring multi-hop mesh topologies. 802.11T Recommended practices on measurement methods, performance metrics and test procedures to assess the performance of 802.11 equipment and networks. The capital T denotes a recommended practice rather than a technical standard. 802.11u Amendments to both PHY and MAC layers to provide a generic and standardised approach to inter-working with non-802.11 networks, such as Bluetooth, ZigBee and WiMAX. 802.11v Enhancements to increase throughput, reduce interference and improve reliability through network management. 802.11w Increased network security by extending 802.11 protection to management as well as data frames. services specified in the 802.2 standard, which are also used by Ethernet (802.3) networks, and provide the link to the Network layer and higher layer protocols. 802.11 networks are composed of three basic components; stations, access points and a distribution system, as described in Table 6-2. In the 802.11 standard, WLANs are based on a cellular structure where each cell, under the control of an access point, is known as a basic service Network layer Logical Link Control (LLC) Data Link layer Medium Access Control (MAC) Physical layer Physical layer (PHY) OSI Model layers 802.11 specifications Figure 6-1: 802.11 Logical Architecture Chapter Six set (BSS). When a number of stations are working in a BSS it means that they all transmit and receive on the same RF channel, use a common BSSID, use the same set of data rates and are all synchronised to a common timer. These BSS parameters are included in "beacon frames" that are broadcast at regular intervals either by individual stations or by the access point. The