Standards & SBI coverage

A capability map of the 3GPP interfaces, protocols, and SBI services dflux TinyCore implements — and what it deliberately leaves out.

dflux TinyCore targets the parts of the 3GPP 5G core needed to register a UE, authenticate it, and bring up a PDU session in a lab. This page is a high-level coverage map, not an endpoint-by-endpoint catalogue. Coverage levels are read as: Supported — the main flows work end to end; Partial — implemented for core paths with gaps; Planned — not implemented yet.

Interfaces & protocols

Interface	Protocol	Spec	Support
N1	NAS (UE ↔ AMF)	3GPP TS 24.501	Supported — registration, authentication, PDU-session NAS.
N2	NGAP (gNB ↔ AMF, over SCTP)	3GPP TS 38.413	Supported — NG setup, UE context, PDU-session resource setup.
N4	PFCP (SMF ↔ UPF)	3GPP TS 29.244	Supported — node association and session establish/modify/delete.
N3	GTP-U (gNB ↔ UPF)	3GPP TS 29.281	Partial — forwarded by the userspace datapath; the default stub datapath is control-plane only.
SBI	HTTP/2 + JSON between NFs	3GPP TS 29.500 / 29.501	Supported — h2c (cleartext) by default; TLS / mTLS optional on the NRF.

SBI services by NF

The service-based interfaces each network function exposes, with the 3GPP specification that defines them:

NF	Service	Spec	Support
NRF	Nnrf_NFManagement	3GPP TS 29.510	Supported — register, update, deregister, heartbeat, status subscriptions.
NRF	Nnrf_NFDiscovery	3GPP TS 29.510	Supported — NF instance search with filters.
NRF	Nnrf_AccessToken (OAuth2)	3GPP TS 29.510	Supported — token endpoint; enforcement is opt-in (`-oauth2`).
DMF (AMF)	Namf_Communication	3GPP TS 29.518	Supported — UE-context and N1/N2 message transfer for registration and PDU sessions.
DMF (SMF)	Nsmf_PDUSession	3GPP TS 29.502	Supported — create / update / release SM contexts.
DPF (AUSF)	Nausf_UEAuthentication	3GPP TS 29.509	Supported — 5G-AKA and EAP-AKA' authentication.
DPF (UDM)	Nudm_SDM / UECM / UEAU	3GPP TS 29.503	Supported — subscription-data retrieval, UE-context registration, auth-vector generation.
DPF (PCF)	Npcf_AMPolicyControl / SMPolicyControl	3GPP TS 29.514	Partial — AM- and SM-policy associations for the default flows; advanced policy is limited.

The DPF rolls four NFs into one

AUSF, UDM, UDR, and PCF are separate network functions in the 3GPP architecture. dflux TinyCore bundles them into a single DPF process that registers each as its own NF type with the NRF. See NF discovery.

Out of scope

To stay small and lab-focused, dflux TinyCore deliberately omits carrier-scale features. These are exclusions, not bugs:

Network slicing beyond basic S-NSSAI carried through registration and session setup (optional NSSF process exists for slice selection — see d3x-core-nssf CLI).
Advanced SMS interworking beyond the optional SMSF process (see d3x-core-smsf CLI).
Roaming — single-PLMN home routing only; no N32 / SEPP.
Handover and Xn/N2 mobility — labs assume a single gNB and a single AMF.

For how these interfaces fit together at runtime, see Interfaces and NF discovery.