5gc_amf

AMF - Access & Mobility Management Function

The AMF makes the signaling connection with UE and helps UE to register.

Handles connection and management mobility tasks. As the AMF performs the role of access point to 5G Core, terminating RAN control plane and UE traffic originating on the N1 and N2 reference interfaces, it is responsible for NAS ciphering and integrity protection algorithms [AMF:2].

Mobility Management in the 5G SBA

Mobility management is a key function in any network, as it's responsible for the tracking, registration, management, and authorization of network connections - and access to subscribed services- as devices roam between base stations.

Functions and Responsibilities:

Registration Management
Reachability Management
Connection Management
Mobility Management
Authentication and Authorization
Security and Context Management
It also selects appropriate:
- Authentication Server Function (AUSF)
- Unified Data Management (UDM)
- Policy Control Function (PCF)
- Session Management Function (SMF)
- Network Slice Selection Assistance Information (S-NSSAI)
- Short Message Service Function (SMSF)

Also you can examine the 5G call flow process from the [AMF:1] text given below.

AMF Procedures

Registration Procedure: The AMF manages the registration process for UEs, which includes sending a registration request, authenticating the user, and establishing a connection [8] [9].
Service Request Procedure: The AMF handles service requests from UEs, which establishing a connection and allocating resources.
Handover Procedure: The AMF manages handovers between different access networks, assuring seamless mobility and minimizing service disruptions.
1. Xn Handover: The AMF supports Xn handover, used to handover a UE from source NG-RAN to target NG-RAN using Xn when the AMF is unchanged [6].
2. N2 Handover: The AMF supports inter-AMF and intra-AMF N2 handovers. These can be triggered due to new radio conditions/load balancing, if there is no Xn connectivity between source and target NG-RAN or due to AMF change [5].

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