The wireless mesh network(WMN) is a wide network over globe . It is a multi-hop network which is made of static as well as the Mobile nodes which are connected with each other via special node called routers and Backbone gateways. As the infrastructure of WMN is large and it is multi-hop . It is difficult to provide security easily at different communications links. WMN is made up of many type communication media such as wired such as co-axial cable to optical fiber and Wireless Media such as low length WI-FI to high range and capacity Wimax. So it is heterogonous in nature. Due to heterogeneity, security lapses are much more over WMN. There my be several type of attacks which affects the data unlawfully. There are many security mechanisms are deployed which according to transmission media provide adequate security and make WMN a safe network for data transmission. We discussed threats and there possible solution using security mechanisms This paper serves a baseline for developing a secured, full-proof WMN which takes care of all types of attacks.