For anyone working on 5G Core, RAN, or UE integration, a solid understanding of the end-to-end signaling involved in UE registration and PDU session establishment is critical.
This illustration outlines the full procedure from DL/UL Synchronization to PDU Session Establishment, including all key layers and interfaces:
At high level, 5G SA Registration call flow includes following Steps and shown in following figure:
- Achieving DL/UL sync via SSB decode and RACH Procedure
- SRB0 establishment with RRC Connection Request
- Contention Resolution and SRB1 establishment with RRC setup
- Registration Request
- NAS Procedures like UE Identity transfer, Authentication and Security
- AS UE Capability transfer and AS security
- SRB2 and DRB establishment
- Registration Complete and PDU session Establishment
****IEs Table added for each procedure *****
Use Cases: This is foundational for:**
5G NSA/SA deployment validation
UE bring-up and conformance testing
Core network integration
Packet data flow setup via PDU sessions (e.g., for slicing or QoS policies)
Whether you’re debugging attach failures or building new 5G services, having visibility into each signaling step is invaluable.
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