The Controller Area Network ( CAN) is currently employed in many distributed real-time control applications in the industrial environments. CAN-based distributed control systems have two main problems. These are the size of distributed area and the need for communication with other LANs and with remote CAN segments. A straightforward solution is to use interworking devices with wireless support to extend CAN segments, exploiting an IEEE 802.11 WLAN that is nowadays a low cost technology with high data rates. This research study aims at designing and implementing such an interworking device called Wireless Internetworking Unit (WIU) that is capable of connecting remote CAN 2.0A nodes over IEEE 802.11b WLAN using encapsulation method. Computer modeling and simulation of the proposed approach realized using OPNET Modeler and analysis of the simulation results obtained are also presented.