ational Conference on Computer and Information Technology, p. 99. C 2009 by Taylor & Francis Group, LLC Compliance and Interoperability Testing of SIP Devices Doris Bao, Luca De Vito, Sergio Rapuano, and Laura Tomaciello University of Sannio CONTENTS 8.1 Protocol Testing Protocol Testing Methods SIP Testing Tools 8.4 Case Study: Validation of the INVITE Client Transaction 8.5 Conclusions and Future Directions References The Session Initiation Protocol (SIP) standards [1-5] define a common inter- face for SIP products made by different manufacturers. If all products of a network are compliant to the same standards, they can interoperate each other and a well-defined set of features can be provided to the users. However, SIP standards can lead to different implementations. SIP products, which are independently developed by different vendors, need compliance and interop- erability tests to obtain a problem-free integration. While developing a SIP network device, an essential phase is, therefore, the verification of the compli- ance to the standards and the interoperability with other implementations of the same reference standards. This chapter is organized in four main parts. In the first part, the defi- nitions and characteristics of the compliance and interoperability testing of network protocols are presented. Then, the methods to perform such testing on SIP entities, which are commonly used in the industry and the research, are reported. Moreover, a summary of commercially available instruments and tools that provide assistance in the analysis, implementation, and robustness verification of the SIP protocol is presented. Finally, a SIP validation case study is examined in order to clarify the investigated methods and concepts. Protocol Testing Protocol testing is used to benchmark performance of the SIP device with respect to standard features and to the other products existing in the market. © 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security This is particularly true in th