The present document describes the Abstract Test Suite (ATS) to test interoperability at IMS NNI for IP multimedia call control protocol based on TS 124 229 [i.1] including Rich Communication Suite (RCS) release 2.0. The ATS has been specified on the basis of the Test Descriptions for IMS NNI interoperability testing for RCS presented in TS 102 901 [i.2] and extents TS 186 011-3 [i.3]. It defines a TTCN-3 framework as well as codec and adapter requirements for analysing interoperability test execution traces generated from the manual or automatic execution of IMS interoperability tests. The scope of this ATS is not to cover all requirements specified in TS 124 229 [i.1]. It only assesses requirements that are observable at the NNI between two IMS core network implementations specified in TS 102 901 [i.2].