ECM vs EMM in LTE: Connection and Mobility Management

This page outlines the functional differences between ECM and EMM, as used in LTE. In LTE technology, ECM stands for EPS Connection Management, while EMM stands for EPS Mobility Management.

• These are parts of NAS (Non-Access Stratum). • NAS is primarily used to transport non-radio signaling messages between the UE (User Equipment) and MME (Mobility Management Entity) in LTE. • NAS resides on top of the control plane in the protocol stack. • The procedures used in NAS are divided into two parts: EMM and ESM (EPS Session Management).

Figure 1: Location of NAS (ECM, EMM) in the LTE protocol stack.

LTE ECM | EPS Connection Management

• ECM stands for EPS Connection Management. • It manages the signaling connectivity between two LTE entities: the UE and the EPC (Evolved Packet Core). • There are two states in ECM: ECM IDLE MODE and ECM Connected MODE.

Figure 2: ECM states.

LTE EMM | EPS Mobility Management

• EMM stands for EPS Mobility Management. • EMM deals with mobility management procedures, such as the TAU (Tracking Area Update) procedure and the Attach procedure. • The EPS mobility management states are: EMM De-registered and EMM Registered.

Figure 3: EMM states.