Verifying a UMTS Protocol Using Spin and EASN

In this paper, we consider model checking the RLC protocol in the UMTS system that is seeing ongoing development as a third generation mobile communication system. We briefly describe EASN, a model checker wherein the behavior can be formally specified through a language based upon Promela for control structures but with data models from ASN.1. We discuss the verification problem for RLC and then discuss the results of using EASN on the verification problem and compare with Spin which also is the basis for the EASN realization. As a side-effect of realizing EASN, we have been able to locate some intricate performance bugs in the Spin implementation. We believe that this type of “n-version” programming is necessary to increase confidence in model checkers.