Abstract: The architecture of cognitive network based on congnitive layer is proposed.Characteristics of the architecture can be found as follows.Firstly the cognitive layer independent of traditional OSI seven layers can realize the modularity and reduce the complexity of the network implementation.Secondly,implementation modules of cognition are given in cognitive layer,especially demonstrating certain methods to realize two kinds of cognition,which implement the off-line learning based on genetic algorithms,and implement the real-time decision based on case-based reasoning.Finally,an example of using the cognitive layer to control the data flow in heterogeneous network through reconfiguring network parameters is given.Simulation result shows that the performance is greatly improved when the mechanism of cognition is adopted.