4g Lte Evolved Packet Core Epc Concepts And Call Flows Download Hot | _top_

Manages user data during inter-eNodeB handovers. DL Packet Buffering: Buffers downlink packets for idle UEs. C. PDN Gateway (P-GW / PDN GW)

The UE is already attached (Idle or Connected state).

The MME instructs the S-GW and P-GW to create a session (Create Session Request). Manages user data during inter-eNodeB handovers

The MME serves as the primary control-plane node. It manages session states, tracks user equipment (UE) locations, and handles security keys. It also authenticates users by interacting with the HSS. 2. Serving Gateway (S-GW)

Connects the MME to the S-GW for bearer management control. PDN Gateway (P-GW / PDN GW) The UE

Handles control signaling between the MME and the S-GW.

These components communicate via standardized interfaces such as (control plane between eNB and MME), S1-U (user plane between eNB and S-GW), X2 (direct eNB-to-eNB communication), and Diameter interfaces like S6a (MME to HSS). It manages session states, tracks user equipment (UE)

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Handover is the procedure that moves a connected UE from one cell to another without dropping the call or session. There are two primary types:

: The main user-plane gateway and the mobility anchor for the UE. It routes and forwards user data packets, manages handovers by switching the data path, and buffers downlink data for UEs in idle mode, triggering paging when data arrives.

MME sends "Attach Accept" to the UE via eNodeB.