Cognitive Radio (CR) and Cognitive Network (CN) are proposed to meet requirements of increasing network dependability, availability and adaptability. Aiming current network puzzles, background and technical traits of CR are introduced firstly and concepts of CN are explained. Then, relevant research works of CN are summed up. Based on above expatiation, general architecture of CN is given and its resource management mode is elaborated. Finally, conclusion is drawn and future works are prospected.