e management 2.4. X2-AP protocol 2.4.1. Mobility management 2.4.2. Load management 2.4.3. X2 interface management 2.5. GTPv2-C protocol 2.5.1. Bearer management 2.5.2. Mobility management 2.6. SIP protocol 2.6.1. Requests 2.6.2. Responses 2.7. SDP protocol 2.8. DIAMETER protocol 2.8.1. Application to EPS network 2.8.2. Application to IMS network 2.8.3. Application to PCC function Chapter 3. Basic Procedures 3.1. Attachment 3.2. Registration 3.3. Deregistration 3.4. Detachment 3.5. Establishment of VoLTE session 3.5.1. Originating side 3.5.2. Terminating side 3.6. Termination of VoLTE session 3.6.1. Initiated side 3.6.2. Received side 3.7. Establishment of ViLTE session 3.8. Termination of ViLTE session 3.9. Emergency call Contents Chapter 4. Radio Interface Procedures 4.1. Radio interface 4.1.1. Data link sub-layer 4.1.2. Logical channels 4.1.3. Transport channels 4.1.4. Physical layer 4.1.5. Physical signals 4.1.6. Physical channels 4.2. Procedures 4.2.1. Access control 4.2.2. Data transfer Chapter 5. Service Profiles 5.1. Subscription data 5.1.1. Subscription to the EPS network 5.1.2. Subscription to the IMS network 5.2. VoLTE profile service 5.2.1. Supplementary telephone services 5.2.2. Audio flow 5.3. ViLTE profile service 5.3.1. Supplementary conversational video service 5.3.2. Video flow Chapter 6. Interconnections 6.1. Interconnection CS network 6.1.1. Functional architecture 6.1.2. Protocol architecture 6.1.3. Session establishment 6.1.4. Session termination 6.2. Interconnection with IMS network 6.2.1. Functional architecture 6.2.2. Session establishment Chapter 7. Handover 7.1. Introduction 7.2. Handover based on X2 7.2.1. Handover based on X2 without relocation 7.2.2. Handover based on X2 with relocation 7.3. Handover based on S1 7.3.1. Handover based on S1 without relocation 7.3.2. Handover based on S1 with relocation VoLTE and ViLTE 7.4. PS-PS inter-system handover 7.4.1. Functional architecture 7.4.2. Procedure Chapter 8. Roaming 8.1. Functional architecture 8.1.1. Roaming applied to the EPS network