The CAN is used in many distributed real-time control applications in industrial environments where basically there are two main problems. These are namely the size of distributed area and the need for communication with other LANs and with independent CAN segments. A practical solution is to use interworking devices with wireless support to extend CAN segments, utilizing an IEEE 802.11b WLAN. Main objective of this research work is to design and implement such an interworking device called Wireless Interworking Unit enabling remote CAN2.0A nodes to communicate over IEEE 802.11b WLAN using encapsulation method. Computer modeling and simulation of the new approach are realized by using OPNET Modeler and analysis of the simulation results obtained are also presented.