Each day, the dream of seamless networking and connectivity everywhere is getting closer to become a reality. In this regard, mobile Ad-Hoc networks (MANETs) have been a hot topic in the last decade; but the amount of MANET usage nowadays confines to a tiny percentage of all our network connectivity in our everyday life, which connectivity through infrastructured networks has the major share. On the other hand, we know that future of networking belongs to Ad-Hocing , so for now we try to give our everyday infrastructure network a taste of Ad-Hocing ability; these types of networks are called Wireless Mesh Networks (WMN) and routing features play a vital role in their functionality. In this thesis we examine the functionality of 3 Ad-Hoc routing protocols known as AODV, OLSR and GRP using simulation method in OPNET17.5. For this goal we set up 4 different scenarios to examine the performance of these routing protocols; these scenarios vary from each other in amount of nodes, background traffic and mobility of the nodes. Performance measurements of these protocols are done by network throughput, end-end delay of the transmitted packets and packet loss ratio as our performance metrics. After the simulation run and gathering the results we study them in a comparative view, first based on each scenario and then based on each protocol. For conclusion, as former studies suggest AODV, OLSR and DRP are among the best routing protocols for WMNs, so in this research we don’t introduce the best RP based on the obtained functionality results, instead we discuss the network conditions that each of these protocols show their best functionality in them and suggest the best routing mechanism for different networks based on the analysis from the former part.