CPN modeling and analysis of L2TP

L2TP is an important tunneling protocol in IP VPN. Coloured Petri nets (CPN) is a well- suited formal approach for modeling and analysis of network protocol. Upon the introduction to CPN and L2TP hierarchical and timed CPN is used to create the model of L2TP Then the occurrence graph is analyzed. With this model, we test the protocol behavior to verify its applicability and feasibility. Moreover, we find an exception that L2TP did not define when tunnels are establishing concurrently and then give the solution. This model can also be referred for programming of L2TP.