IEEE 802.11 is described as set of standards that carry out (WlAN) Wireless local area network in computer communication in the 5 GHz and 2.4, 3.6. These sets are created and also maintained by IEEE LAN/ MAN Standard Committee (IEEE 802).The base current version of these sets of standard is IEEE 802.11-2007.Its main purpose is to develop (CSMA/ CA)Carrier Sense Multiple Access/ Collision Avoidance which is based at (WLNA) Wireless Local Area Network standards that is within IEEE802.

Limitation and the success of Ethernet, together with the proliferation of mobile computing devices and laptops created significant market demands for all wireless computer networks. Originally Wireless Ethernet was intended to provide some connectivity wiring in premises’ is inadequate in supporting LANs. Therefore Ethernet requires special cables known as CAT5. Another motivation of Ethernet was allocation of 2.4GHz band for all unlicensed devices by the FCC. 802.11 has only one MAC protocol. Recently it has undergone significant development.

Security is one of the major issues in network processes. Normally security threats arise without anyone noticing. Therefore any network must know how to prevent this threat. Nevertheless, connections must be established before any exchange of data. In order to establish a network authentication, scan and association is necessary. Scanning discovers any existence f BSSs that might be within the range. In a wired LAN, if in any way a station can connect to the network physically, it is authenticated. Therefore authentication is also necessary in wireless network. Thus the protocol through which various stations prove their identities is through security mechanism- authentication. Authentication is not enough in providing security because the wireless medium is still open to any attacker. Therefore the frame requires to be cryptographically protected through tying key to the original authentication. Decryption and encryption form the privacy mechanism. As a result what IEEE 802.11 offers some security services that protects the above threats. They include: key distribution, replay protection, authentication and privacy.

IEEE 802.11 Standard Architecture shows how the system is separated into four major parts. This includes: MCA of data link layer, the PHY, IEEE 802.IX and also upper layer authentication protocols. MAC sub layer and 802.1X layer are found in data link layer. Authorization Agent (AA) and 802.1X act as the security sub layer. Physical layer have two sub layers: physical medium- dependent (PMD) and physical convergence protocol (PLCP) sub layer. The MAC and PHY have management sub-entities that communicate with station management entity. A Robusta security network normally requires three components. These components have been developed outside 802.x11. IEEE 8021X port is the first new component. It determines when some traffic across 802.11 wireless links. Authentication Agent is the second new component. It resides on top of IEEE 802.11 station. The third new component is authentication server AS which is not part of 802.11 stations.

Each computer, mobile, fixed or portable, is known as station in 802.11(Wireless Local Area networks. Therefore when two or more join together in order to communicate they form (BSS) basic Service Set. The minimum Basic Set Service consists of two stations. Thus 802.11 LANS normally uses BSS as major standard building block. BSS which is not connected to the base and usually stands alone is known as Independent Basic Set (IBSS) which is also referred to as Ad-Hoc Network. Thus IBSS is a network which stations communicate only peer to peer. Group of BSS can also be combined to form (ESS) Extended Service Set. Its main purpose is to support both IBSS and BSS. Another thing is decision making in BSS I centralized while in IBSS decision making is always distributed.

IAPP Inter- Access point Protocol is also required in local wireless networking. First, in order to achieve roaming capability APs must communicate among themselves. They are usually connected through abstract layer, known as distribution system (DS). Anew protocol called inter-access point protocol is used across DS. The new protocol is known as 802.11 adopted in 2002. In the network the IAPP does not only affect APs. It affects other devices such as layer 2 networking devices for instance, switches and bridges. On the other hand the major goal of IAPP is to make sure that station is associated with at least one AP, as it continues to roam within the ESS. The main goal of single association is normally achieved using registration protocol that is developed by the IETF known as Service Location Protocol (SLP). Therefore, this registration service can even be hosted on a server that is independent or even be contained within an AP. Another goal is that APs interoperable.

Association with a new AP may be accomplished through two commands that are association and reassociation. Therefore, the IAPP tends to work in different ways depending on whether any roaming station chooses to use reassociation or association. The APME always generate proper request to the IAPP every time when the station is associating with a new AP. The IAPP try to enforce one single station association requirement through sending an LAPP ADD- notify packet to the DS. This informs other layer 2 devices and also APs. As a result two changes are caused that is forwarding tables are updated. The second change caused is that every AP that normally receives the ADDS- packet checks if the roaming station was not associated previously. If it was then it disassociates. Thus, it removes any context stored for the station. After reassociating the AP informs IAPP of the BSSID of the AP with which the station was associated previously. Thus the context that is from the old station is forwarded to the new AP.

When 802.11 started working on the MAC that is 1990, it was supposed to be used for computer data communication that is real- time data. Therefore, audio and voice were not put into consideration. This is because of its CSMA nature that is optimal for only computer data communication. However data communication systems are being used to transport real-time data such as video, audio and voice. In order to achieve this different networks are trying to provide different levels of quality services(QoS) Thus nature of real-time traffic is very different from data application. The major QoS factors include; end- to-end delay, latency jitter, bandwidth, signal quality and packet loss, service availability, and capability to offer services differentiation.

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