Vulnerability of communication protocols can cause denial-of-service (DoS) attacks, which cause significant damage to systems connected to the internet. therefore, analysis of resistance against DoS attacks is important. previously, we developed a formal framework for DoS attack resistance, the spice calculus. here, we propose a method for analyzing communication protocols from the viewpoint of DoS attack resistance. in this method, we first formulate a communication protocols in terms of the spice communications protocol in terms of the spice calculus. then we translate expressions of the spice calculus into timed automata and analyze them using the real-time model checker UPPAAL. the method is explained here by showing an example of a simple communication protocol.