1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Reference model of lite IMS
7 Signalling architecture of lite IMS
7.1 Unified control function
7.2 Service enabler function
7.3 Service user profile function
7.4 End-user function
7.5 Transport control function
7.6 Service and application function
8 Functional entities of lite IMS
8.1 Functional entities in unified control function
8.2 Functional entities in a service user profile function
8.3 Functional entities in a service enabler function
9 Reference points of lite IMS
9.1 Reference point U1
9.2 Reference point U2
9.3 Reference point L1
9.4 Reference point L2
9.5 Reference point L3
9.6 Reference point L4
9.7 Reference point L5
10 Relationship between lite IMS and IMS
11 Security consideration
Appendix I – Application programming interface format
I.1 Examples of API format