7.4. Reference Points
The following table lists the reference points in the reference point representation figure. TS 23.501 clause 4.2.7 defines all of these reference points except Uu and Xn, which TS 38.300 defines for the NG-RAN.
| Reference point | Between | Specification | Protocol |
|---|---|---|---|
Uu |
UE and NG-RAN |
TS 38.331 |
Radio Resource Control (RRC) |
Xn |
Two NG-RAN nodes |
TS 38.423 |
Xn Application Protocol (XnAP) |
N1 |
UE and AMF |
TS 24.501 |
NAS |
N2 |
NG-RAN and AMF |
TS 38.413 |
NG Application Protocol (NGAP) |
N3 |
NG-RAN and UPF |
TS 29.281 |
GTP version 1 for the user plane (GTPv1-U) |
N4 |
SMF and UPF |
TS 29.244 |
Packet Forwarding Control Protocol (PFCP) |
N5 |
PCF and AF |
TS 29.514 |
HTTP/2 |
N6 |
UPF and DN |
TS 29.561 |
IP |
N7 |
SMF and PCF |
TS 29.512 |
HTTP/2 |
N8 |
UDM and AMF |
TS 29.503 |
HTTP/2 |
N9 |
Two UPFs |
TS 29.281 |
GTPv1-U |
N10 |
UDM and SMF |
TS 29.503 |
HTTP/2 |
N11 |
AMF and SMF |
TS 29.502 |
HTTP/2 |
N12 |
AMF and AUSF |
TS 29.509 |
HTTP/2 |
N13 |
UDM and AUSF |
TS 29.503 |
HTTP/2 |
N14 |
Two AMFs |
TS 29.518 |
HTTP/2 |
N15 |
PCF and AMF |
TS 29.507 |
HTTP/2 |
N17 |
AMF and 5G-EIR |
TS 29.511 |
HTTP/2 |
N22 |
AMF and NSSF |
TS 29.531 |
HTTP/2 |
N23 |
PCF and NWDAF |
TS 29.520 |
HTTP/2 |
N28 |
PCF and CHF |
TS 29.594 |
HTTP/2 |
N29 |
NEF and SMF |
TS 29.508 |
HTTP/2 |
N30 |
PCF and NEF |
TS 29.514 |
HTTP/2 |
N33 |
NEF and AF |
TS 29.522 |
HTTP/2 |
N34 |
NSSF and NWDAF |
TS 29.520 |
HTTP/2 |
N35 |
UDM and UDR |
TS 29.504 |
HTTP/2 |
N36 |
PCF and UDR |
TS 29.504 |
HTTP/2 |
N37 |
NEF and UDR |
TS 29.504 |
HTTP/2 |
N40 |
SMF and CHF |
TS 32.291 |
HTTP/2 |
N41 |
AMF and CHF |
TS 32.291 |
HTTP/2 |
N51 |
AMF and NEF |
TS 29.518 |
HTTP/2 |
N52 |
NEF and UDM |
TS 29.503 |
HTTP/2 |
N58 |
AMF and NSSAAF |
TS 29.526 |
HTTP/2 |
N59 |
UDM and NSSAAF |
TS 29.503 |
HTTP/2 |
N80 |
AMF and NSACF |
TS 29.536 |
HTTP/2 |
N81 |
SMF and NSACF |
TS 29.536 |
HTTP/2 |
N82 |
NSACF and NEF |
TS 29.536 |
HTTP/2 |
N83 |
AUSF and NSSAAF |
TS 29.526 |
HTTP/2 |