Section: 4.6 EPS Mobility Management and Connection Management states 4.6.1 General
Content: The EPS Mobility Management (EMM) states describe the Mobility Management states that result from the mobility management procedures e.g. Attach and Tracking Area Update procedures. Two EMM states are described in this document: - EMM-DEREGISTERED. - EMM-REGISTERED. NOTE 1: Other specifications may define more detailed EMM states (see e.g. TS 24.301[ Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 ]  [46]). The EPS Connection Management (ECM) states describe the signalling connectivity between the UE and the EPC. Two ECM states are described in this document: - ECM-IDLE. - ECM-CONNECTED. NOTE 2: The ECM-CONNECTED and ECM-IDLE states used in this document correspond respectively to the EMM-CONNECTED and EMM-IDLE modes defined in TS 24.301[ Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 ]  [46]. In general, the ECM and EMM states are independent of each other. Transition from EMM-REGISTERED to EMM-DEREGISTERED can occur regardless of the ECM state, e.g. by explicit detach signalling in ECM-CONNECTED or by implicit detach locally in the MME during ECM-IDLE. However there are some relations, e.g. to transition from EMM-DEREGISTERED to EMM-REGISTERED the UE has to be in the ECM-CONNECTED state.