ns document, 802.11b, adds increased data rates and other features while retaining compatibility with equipment Data security Blowfish encryption algorithm (over using the DSSS physical layer of the basic specification. 1 trillion codes) Supplement 802.11 specifies considerably higher rate Data compression LZRW3-A (Lempel-Ziv) algorithm operation in bands of frequencies between 5.2 and 5.8 GHz. These data rates were made available on the 2.4 48-bit network ID Enables concurrent operation of multiple co-located networks GHz band by 802. 11g that has downward compatibility with 802.11b. Short-range wireless applications and technologies CHAPTER 5.2 Network architecture Wi-Fi architecture is very flexible, allowing considerable STA 4 mobility of stations and transparent integration with STA 1 wired IEEE networks. The transparency comes about STA 3 because upper application software layers (see below) are not dependent on the actual physical nature of the communication links between stations. Also, all IEEE Figure 5.2-2 Distribution system and access points. LAN stations, wired or wireless, use the same 48-bit addressing scheme SO an application only has to reference They are authentication and encryption. Authentication source and destination addresses and the underlying is the procedure used to establish the identity of a station lower-level protocols will do the rest. as a member of the set of stations authorized to associate Three Wi-Fi network configurations are shown in with another station. Encryption applies coding to data to Figures 5.2-1 through 5.2-3. Figure 5.2-1 shows two prevent an eavesdropper from intercepting it. 802.11 unattached basic service sets (BSS), each with two sta- details the implementation of these services in the MAC. tions (STA). The BSS is the basic building block of an Further protection of confidentiality may be provided by 802.11 WLAN. A station can make ad hoc connections higher software layers in the network that are not part of with other stations within its wireless communicatio