5G • Core Network
PSA
PDU Session Anchor UPF
The User Plane Function terminating the N6 interface that allocates IP addresses and anchors user sessions.
Technical Explanation
The PDU Session Anchor (PSA) is the authoritative UPF terminating the N6 interface to the external Data Network. It allocates the UE's IP address, applies session-level charging and rate policing (Session-AMBR), and anchors user traffic against geographic mobility.
Key Functions
- Terminates N6 interface to external Data Network (Internet/IMS)
- Allocates and anchors the user's IP address or IPv6 prefix
- Enforces session-wide rate policing and collects accounting telemetry
Specifications
3GPP TS 23.501
Interfaces
N6N4N9
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