Twelve functions. One bus.
Click any of them.
The catalogue of 5G Core NFs — AMF, SMF, UPF, AUSF, UDM, UDR, PCF, NRF, NSSF, NEF, NWDAF, AF — with the reference points that stitch them together. Click any block in the live map for its role, service operations, interface graph and what it means for a satellite deployment.
The whole 5G Core — click any function.
The full service-based architecture of TS 23.501: control-plane NFs hang off the shared SBI bus; the AMF and SMF bridge down to the reference-point world of UE, gNB, UPF and Data Network. Click any block — a panel opens with an animated interface map of every reference point it terminates, its service operations and NTN relevance.
Each function, one line on the satellite question.
Only the gNB and UPF can realistically ride the satellite. Everything else stays on the ground — but each function still has to cope with the feeder-link delay. Here is the one-liner for each.
AMF
One AMF serves a UE across fast-moving LEO cells; T3512 stretched; N2 over feeder RTT.
SMF
Selects an edge/onboard UPF for regenerative payloads; keeps sessions across beam handovers.
UPF
The one NF that can ride the satellite — onboard or edge; store-and-forward.
AUSF
Auth round-trips cross the long RTT — kept minimal; stays ground-based.
UDM
Subscription-based access control per satellite coverage / regulatory area.
UDR
System-of-record stays on the ground; onboard NFs query or cache over the feeder.
PCF
QoS that respects satellite delay; URSP steers TN vs NTN slices.
NRF
Registry stays on the ground even when gNB/UPF are onboard.
NSSF
TN↔NTN slice continuity; a dedicated S-NSSAI for satellite access.
NEF
Exposes satellite coverage windows & UE location to IoT/enterprise AFs.
NWDAF
Predicts satellite handovers & coverage gaps for proactive slice/UPF selection.
AF
Edge apps request local breakout to an onboard/edge UPF, delay-aware QoS.
Sources & specifications
- TS 23.501 — 5G System architecture · §6.2 NFs
- TS 23.502 — 5G System procedures
- TS 24.501 — NAS · N1
- TS 38.413 — NGAP · N2
- TS 29.244 — PFCP · N4
- TR 38.821 — NTN architecture