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Protocols

Protocols we speak.

A reference for the 3GPP protocols and interfaces the dflux tools put on the wire — each with its specification and the products that use it. We list what we use; we don't invent coverage percentages.

By protocol

Control plane, user plane, SBI.

The wire-level surface across the toolkit, organized by protocol and 3GPP reference point.

NGAP

3GPP TS 38.413
N2 — gNB ↔ AMF
over SCTP (RFC 4960)

NG Application Protocol carries control signaling between the gNB and the AMF — NG setup, UE context management, and PDU-session resource setup. NAS messages ride inside it.

NAS (5GS)

3GPP TS 24.501
N1 — UE ↔ AMF
tunneled in NGAP over N2

Non-Access Stratum signaling between the UE and the core: registration, authentication (5G-AKA), security mode, PDU-session NAS, and SMS over NAS. It has no transport of its own and is carried inside NGAP.

PFCP

3GPP TS 29.244
N4 — SMF ↔ UPF
over UDP

Packet Forwarding Control Protocol — how the SMF programs the UPF: node association and session establishment, modification, and deletion, plus the forwarding rules for UE packets.

GTP-U

3GPP TS 29.281
N3 — gNB ↔ UPF
over UDP

GPRS Tunneling Protocol, user plane — encapsulates UE user-plane packets between the gNB and the UPF. dflux Runner generates GTP-U user-plane traffic; dflux TinyCore forwards it on its userspace datapath.

In dflux TinyCore, N3 / GTP-U forwarding is handled by the userspace datapath; the default stub datapath is control-plane only.

User-plane data (N6)

IP over TUN
N6 — UPF ↔ data network
userspace datapath

The data-network side of the UPF. In dflux TinyCore the UPF opens a TUN interface and forwards decapsulated UE traffic out through it. This is plain IP, not a 3GPP-specific protocol.

SBI over HTTP/2

3GPP TS 29.500-series
Service-based interfaces
HTTP/2 (h2c by default), JSON

The 5G service-based interfaces between NFs (Namf, Nsmf, Nausf, Nudm, Npcf, Nnrf). NF service framework is TS 29.500; per-NF services live in the 29.5xx specifications (see below).

Diameter

RFC 6733
4G interworking — S6a / Gx / Rx
over TCP or SCTP

Diameter base protocol with the S6a, Gx, and Rx application filters. dflux Runner exercises a vendor's policy plane over Diameter; dflux EdgeGuard relays Diameter through the same policy pipeline it uses for SBI.

S6a / Gx / Rx map to 3GPP TS 29.272 / 29.212 / 29.214 respectively.

SBI services

Service-based interfaces, by NF.

The per-NF service-based interfaces carried over SBI HTTP/2, each defined by its own 3GPP specification.

NFServiceSpec
NRFNnrf_NFManagement / NFDiscovery / AccessTokenTS 29.510
AMFNamf_CommunicationTS 29.518
SMFNsmf_PDUSessionTS 29.502
AUSFNausf_UEAuthenticationTS 29.509
UDMNudm_SDM / UECM / UEAUTS 29.503
PCFNpcf_AMPolicyControl / SMPolicyControlTS 29.514
SMSFNsmsf_SMServiceTS 29.540

Which tool uses what

Protocols by product.

A used / not-used map — not a coverage score. Runner drives procedures as a tester; TinyCore implements the lab core; EdgeGuard fronts SBI and Diameter.

NGAP
NAS (5GS)
PFCP
GTP-U
SBI over HTTP/2
Diameter
Role
Drive procedures as a tester
Govern signaling at the edge
Implement the core

SBI here means the HTTP/2 service framework (TS 29.500-series); per-NF service specs are listed above. Diameter covers the S6a / Gx / Rx application filters over RFC 6733.

Need a specific interface?

Tell us what you need to test.

Looking for a protocol, procedure, or interface that isn't listed? Tell us what you're building and we'll get back to you.