SUMMARYThis paper describes the architecture and operations of a test system NGNAS-SIOTP. NGNAS-SIOTP is designed based on the Testing and Test Control Notation Version 3 (TTCN-3) specifications for the conformance testing of next generation network applications and systems. By specifying conformance test cases in abstract level, the test cases are language and platform-independent, and the implementation of the test cases can be more convenient. We use an Open Mobile Alliance (OMA) Browsing test case of XHTML Structure Module and an IP Multimedia Subsystem (IMS) test case of Replaces Extension Header Field to illustrate how conformance tests can be implemented and conducted in our NGNAS-SIOTP. These test cases conform to the OMA Enabler Test Specification (Conformance) for OMA Browsing and RFC documents for IMS.