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ECM vs EMM in LTE | Functions of ECM and EMM in LTE

This page mentions functional difference between ECM and EMM used in LTE. ECM stands for EPS Connection Management and EMM stands for EPS Mobility Management in LTE technology.

• These are parts of NAS (Non Access Stratum).
• NAS is basically used to transport non radio signalling messages between UE and MME in LTE.
• NAS resides on top of control plane in protocol stack.
• The procedures used in NAS are divided into two parts viz. EMM and ESM (EPS Session Management).


LTE Stack showing NAS-ECM,EMM

The figure-1 depicts the location of NAS (ECM, EMM) in the LTE protocol stack.

LTE ECM | EPS Connection Management

ECM States-IDLE,Connected

• ECM stands for EPS Connection Management.
• It mentions signalling connectivity between two LTE entities viz. UE and EPC (Evolved Packet Core).
• Following are the two states in ECM viz. ECM IDLE MODE and ECM Connected mode. The figure-2 depicts the ECM states.

LTE EMM | EPS Mobility Management

EMM States-registered,de-registered

• EMM stands for EPS Mobility Management.
• EMM deals with mobility management procedures e.g. TAU procedure and Attach procedure.
• Following are the EPS mobility management states viz. EMM De-registered and EMM Registered. The figure-3 depicts the EMM states.

What is difference between

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