ITU Q.3941.2:2011 Network Integration Testing Between Sip And Isdn/Pstn Network Signalling Protocols - Part 2: Abstract Test Suite And Partial Protocol Implementation Extra Information For Testing Proforma Specification For Sip-Isdn Describes the abstract test suite (ATS) and partial protocol implementation extra information for testing (PIXIT) proforma specification for network integration testing (NIT) to verify the overall com