In this section, we describe how an end-host can estimate both the potential upstream and downstream bandwidth between the AP and itself. The final affiliation decision made by the end-host is going to be some function of the upstream and downstream bandwidth and is likely to depend on the user's requirements. For the remainder of this work, we assume that the client has credentials to associate with any AP within range and selects the AP offering the highest bandwidth in the direction the client will use for its data transfer. We begin by providing a brief background of the IEEE 802.11 MAC protocol for data transmission.