This thesis evaluates the performance of the 802.11 wireless network. The newly defined DCF+ protocol performance is studied and compared with the DCF protocol under different traffic conditions. A service differentiation mechanism is also applied to both protocols for basic access mechanism and the efficiency of the protocols is examined. As an additional work, the same study is performed for RTS/CTS access scheme and efficiency of the protocols is examined As a result of this study, it is shown that the DCF+ protocol provides performance enhancement to the DCF protocol under different traffic conditions but fails to provide service differentiation because of its structure.