Foreword1 Scope2 References3 Definitions, symbols and abbreviations4 Overview5 Functional architecture6 Procedures7 Use of transport functions8 Security9 ManagementA.1 Scope of signalling flowsA.2 IntroductionA.3 Signalling flows for registrationA.4 Signalling flows for call originationA.5 Signalling flows for call termination A.1 Scope of signalling flows 24.5253GPPArchitecture and functional descriptionBusiness trunkingRelease 17TS Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM Void.