Key Functions of NFs

NF Expansion and Key Function

5G-EIR 5G- Equipment Identity Register: Records blacklisted device IDs

AF Application Function: Influences traffic routing and facilitates QoS control

AMFAccess and Mobility Management Function: Exchanges NAS signaling with the UE and manages registration, connection, reachability, and mobility

AUSF Authentication Server Function: Authenticates the UE

LMF Location Management Function: Helps determine the UE location

N3IWF Non-3GPP Interworking Function: Supports an IPSec tunnel toward the UE through a non-3GPP access network

NRF Network Repository Function: Supports discovery of NFs/services

NSSAAFNetwork Slice-Specific Authentication and Authorization Function: Provides Network Slice-specific authentication and authorization by relaying Extensible Authentication Protocol (EAP) messages

NSSF Network Slice Selection Function: Determines allowed Network Slices

NWDAF Network Data Analytics Function: Provides Network Slice-specific analytics to an NF

PCF Policy Control Function: Creates policy rules (e.g., to support QoS control)

SCP Service Communication Proxy: Facilitates indirection communication between NFs and NF services

SEPP Security Edge Protection Proxy: Secures inter-PLMN Control Plane interfaces

SMF Session Management Function: Manages UE sessions and allocates an IP address to the UE

SMSF Short Message Service (SMS) Function: Supports SMS over NAS

UDM Unified Data Management: Manages subscriptions and generates authentication credentials

UDR Unified Data Repository: Stores subscription data, policy data, and structured data for exposure

UDSF Unstructured Data Storage Function: Supports storage, modification, and retrieval of unstructured data

UPF User Plane Function: Acts as a mobility anchor for user traffic

Selected Reference Points and Associated NFs

Interface/ Reference Point Associated NFs

N4 SMF-UPF

N5 PCF-AF

N7 SMF-PCF

N8 AMF-UDM

N9 UPF-UPF

N11 AMF-SMF

N12 AMF-AUSF

N13 AUSF-UDM

N14 AMF-AMF

N15 AMF-PCF

N22 AMF-NSSF

N33 NEF-AF

N58 AMF-NSSAAF

N59 NSSAAF-UDM

Governing Protocols on Major Interfaces

Interface/ Reference Point Associated NFs Associated NFs

E1 E1 Application Protocol (E1AP) TS 38.463

F1-C F1 Application Protocol (XnAP) TS 38.473

N1 5G Non-Access Stratum (NAS) Signaling TS 24.501

N2 Next Generation Application Protocol (NGAP) TS 38.413

N3, Xn-U, F1-UGPRS Tunneling Protocol version 1- User Plane (GTPv1-U)

TS 29.281

Xn-C Xn Application Protocol (XnAP) TS 38.423

Service Based Interfaces: N***  (Ex: Nausf)

Application Programming Interfaces (APIs) based on Hyper Text Transfer Protocol (HTTP)/2 protocol with Javascript Object Notation (JSON)

IETF RFC 7540 for HTTP/2, IETF RFC 8259 for JSON, TS 29.5NN for NF services (Ex: 29.500 Overall SBA, 29.502 SMF, 29.503 UDM, 29.518 AMF, and so on based on the NF)

5G NETWORK ARCHITECTURE

www.rohde-schwarz.com

IAB-node gNB

Integrated ng-eNB

Integrated ng-eNB

Integrated gNB

UE

UE

UE

UE

UE

LTE Uu

NR Uu

UE NR Uu

NR UuUE

Backhaul Link (NR Uu, F1)

Backhaul Link (NR Uu)

gNB-CU

Xn-U

gNB-DUgNB-DU gNB-CU-C

gNB-CU-U

IAB-node gNB

IAB-donor gNB

Xn-C

N2

F1-C F1-U

N3

E1

F1

Xn-C and Xn-U

F1-U

F1-C

N2

N3

AMF

UPF

N2

N3

Access Link(NR Uu)

Access Link(NR Uu)

Multi-RAT Connectivity

Overall Service Based Architecture (SBA) NG-RAN Architecture

Disaggregated gNB with Disaggregated gNB-CUDisaggregated gNB

Standalone NR with the 5GC (”Option 2”) Non-Standalone NR with the EPC (“Option 3/3a/3x”)

Option 1: E-UTRA with EPC (Baseline)

Option 2: Standalone NR with NGC

Option 3, 3a, 3x: Non-Standalone NR with EPC

Option 4, 4a: Non-Standalone E-UTRA with NGC

Option 5: Standalone E-UTRA with NGC

Option 6: Standalone NR with EPC

Option 7, 7a, 7x: Non-Standalone NR with NGC

Option 8, 8a: Non-Standalone E-UTRA with EPC

AMF

UPF

UE

N3

N2

NR-UugNB

S-GW

MME

UE

NR-Uu S1-U

S1-U

S1-MME

X2

LTE-Uu

gNB

eNB

PCF UDM AF

AUSF AMF SMF SCP V-SEPP/H-SEPP

Nnssf Nnef Nnrf Npcf Nudm Naf

Nnssaaf Nausf Namf Nsmf

NSSF NEF NRF

NSSAAF

N2

N3 N6UPF

N1

NR-Uu

UE

NR-Uu

Needed for enchanced capability only

Data Network (Ex: Internet, IMS,Enterprise)

NG-RAN

Overall Service Based Architecture3GPP has defined a service-based architecture, where different Network Functions (NFs) provide services via service-based interfaces. For example, other NFs can use Namf interface to obtain services of the AMF.

Multi-RAT ConnectivityA UE may connect to multiple base stations (e.g., eNB and gNB) simultaneously. Two popular network architectures are Standalone NR with the NGC (“Option 2”) and Non-Standalone NR with the EPC (EN-DC or Option 3/3a/3x).

NG-RAN ArchitectureThe Next-Generation Radio Access Network (NG-RAN) consists of NR-based gNBs and LTE-based ng-eNBs. The NG-RAN connects to the 5GC/NGC.

For more Information

Su

stai

nab

le p

rod

uct

des

ign

► E

nviro

nmen

tal c

ompa

tibili

ty a

nd e

co-f

ootp

rint

► E

nerg

y ef

ficie

ncy

and

low

em

issi

ons

► L

ong

evity

and

opt

imiz

ed t

otal

cos

t of

ow

ners

hip

Cert

ified

Qua

lity

Man

agem

ent

ISO

9001

Cert

ified

Env

ironm

enta

l Man

agem

ent

ISO

1400

1

Roh

de

& S

chw

arz

US

A,

Inc.

6821

Ben

jam

in F

rank

lin D

rive

Col

umbi

a, M

D 2

1046

1-88

8-TE

ST-

RS

A (1

-888

-837

-877

2)

ww

w.r

ohde

-sch

war

z.co

m/u

s

R&

S®

is a

reg

iste

red

trad

emar

k of

Roh

de &

Sch

war

z G

mbH

& C

o. K

G

© 2

021

Roh

de &

Sch

war

z G

mbH

& C

o. K

G |

8167

1 M

unic

h, G

erm

any

Serv

ice

that

add

s va

lue

►W

orl

dw

ide

►Lo

cal an

d p

ers

on

aliz

ed

►C

usto

miz

ed

an

d fl

exib

le

►U

nco

mp

rom

isin

g q

ualit

y►

Lo

ng

-term

dep

en

dab

ility

Rohd

e & S

chw

arz

The

Roh

de &

Sch

war

z el

ectr

onic

s g

roup

off

ers

inno

vativ

e so

lutio

ns in

the

fol

low

ing

bus

ines

s

field

s: t

est

and

mea

sure

men

t, b

road

cast

and

med

ia, s

ecur

e co

mm

unic

atio

ns, c

yber

secu

rity,

mon

itorin

g a

nd n

etw

ork

test

ing

. Fou

nded

mor

e

than

80

year

s ag

o, t

he in

depe

nden

t co

mpa

ny

whi

ch is

hea

dqua

rter

ed in

Mun

ich,

Ger

man

y,

has

an e

xten

sive

sal

es a

nd s

ervi

ce n

etw

ork

with

loca

tions

in m

ore

than

70

coun

trie

s.

ww

w.r

ohde

-sch

war

z.co

m

Regi

onal

con

tact

► E

urop

e, A

fric

a, M

iddl

e E

ast

| +49

89

4129

123

45

cust

omer

supp

ort@

rohd

e-sc

hwar

z.co

m

► N

orth

Am

eric

a | 1

888

TE

ST

RS

A (1

888

837

87

72)

cust

omer

.sup

port

@rs

a.ro

hde-

schw

arz.

com

► L

atin

Am

eric

a | +

1 41

0 91

0 79

88

cust

omer

supp

ort.

la@

rohd

e-sc

hwar

z.co

m

► A

sia

Paci

fic |

+65

65

13 0

4 88

cust

omer

supp

ort.

asia

@ro

hde-

schw

arz.

com

► C

hina

| +

86 8

00 8

10 8

2 28

| +

86 4

00 6

50 5

8 96

cust

omer

supp

ort.

chin

a@ro

hde-

schw

arz.

com

5G N

ETW

ORK

ARCH

ITEC

TURE

Po

ster

Key

Func

tions

of N

Fs

NF

Expa

nsio

n an

d Ke

y Fu

nctio

n

5G-E

IR5G

- Equ

ipm

ent I

dent

ity R

egis

ter:

Reco

rds

blac

klis

ted

devi

ce ID

s

AFAp

plic

atio

n Fu

nctio

n: In

fluen

ces

traffi

c ro

utin

g an

d fa

cilit

ates

QoS

con

trol

AMF

Acce

ss a

nd M

obili

ty M

anag

emen

t Fun

ctio

n: E

xcha

nges

NAS

sig

nalin

g w

ith th

e UE

and

man

ages

regi

stra

tion,

co

nnec

tion,

reac

habi

lity,

and

mob

ility

AUSF

Auth

entic

atio

n Se

rver

Fun

ctio

n: A

uthe

ntic

ates

the

UE

LMF

Loca

tion

Man

agem

ent F

unct

ion:

Hel

ps d

eter

min

e th

e UE

loca

tion

N3I

WF

Non

-3GP

P In

terw

orki

ng F

unct

ion:

Sup

ports

an

IPSe

c tu

nnel

tow

ard

the

UE th

roug

h a

non-

3GPP

acc

ess

netw

ork

NRF

Net

wor

k Re

posi

tory

Fun

ctio

n: S

uppo

rts d

isco

very

of N

Fs/s

ervi

ces

NSS

AAF

Net

wor

k Sl

ice-

Spec

ific

Auth

entic

atio

n an

d Au

thor

izatio

n Fu

nctio

n: P

rovi

des

Net

wor

k Sl

ice-

spec

ific

auth

entic

atio

n

and

auth

oriza

tion

by re

layi

ng E

xten

sibl

e Au

then

ticat

ion

Prot

ocol

(EAP

) mes

sage

s

NSS

FN

etw

ork

Slic

e Se

lect

ion

Func

tion:

Det

erm

ines

allo

wed

Net

wor

k Sl

ices

NW

DAF

Net

wor

k Da

ta A

naly

tics

Func

tion:

Pro

vide

s N

etw

ork

Slic

e-sp

ecifi

c an

alyt

ics

to a

n N

F

PCF

Polic

y Co

ntro

l Fun

ctio

n: C

reat

es p

olic

y ru

les

(e.g

., to

sup

port

QoS

cont

rol)

SCP

Serv

ice

Com

mun

icat

ion

Prox

y: F

acili

tate

s in

dire

ctio

n co

mm

unic

atio

n be

twee

n N

Fs a

nd N

F se

rvic

es

SEPP

Secu

rity

Edge

Pro

tect

ion

Prox

y: S

ecur

es in

ter-P

LMN

Con

trol P

lane

inte

rface

s

SMF

Sess

ion

Man

agem

ent F

unct

ion:

Man

ages

UE

sess

ions

and

allo

cate

s an

IP a

ddre

ss to

the

UE

SMSF

Shor

t Mes

sage

Ser

vice

(SM

S) F

unct

ion:

Sup

ports

SM

S ov

er N

AS

UDM

Unifi

ed D

ata

Man

agem

ent:

Man

ages

sub

scrip

tions

and

gen

erat

es a

uthe

ntic

atio

n cr

eden

tials

UDR

Unifi

ed D

ata

Repo

sito

ry: S

tore

s su

bscr

iptio

n da

ta, p

olic

y da

ta, a

nd s

truct

ured

dat

a fo

r exp

osur

e

UDSF

Unst

ruct

ured

Dat

a St

orag

e Fu

nctio

n: S

uppo

rts s

tora

ge, m

odifi

catio

n, a

nd re

triev

al o

f uns

truct

ured

dat

a

UPF

User

Pla

ne F

unct

ion:

Act

s as

a m

obili

ty a

ncho

r for

use

r tra

ffic

Sele

cted

Ref

eren

ce

Poin

ts a

nd A

ssoc

iate

d N

Fs

Inte

rfac

e/ R

efer

ence

Poi

ntAs

soci

ated

NFs

N4

SMF-

UPF

N5

PCF-

AF

N7

SMF-

PCF

N8

AMF-

UDM

N9

UPF-

UPF

N11

AMF-

SMF

N12

AMF-

AUSF

N13

AUSF

-UDM

N14

AMF-

AMF

N15

AMF-

PCF

N22

AMF-

NSS

F

N33

NEF

-AF

N58

AMF-

NSS

AAF

N59

NSS

AAF-

UDM

Gove

rnin

g Pr

otoc

ols

on M

ajor

Inte

rfac

es

Inte

rfac

e/ R

efer

ence

Poi

ntAs

soci

ated

NFs

Asso

ciat

ed N

Fs

E1E1

App

licat

ion

Prot

ocol

(E1A

P)TS

38.

463

F1-C

F1 A

pplic

atio

n Pr

otoc

ol (X

nAP)

TS 3

8.47

3

N1

5G N

on-A

cces

s St

ratu

m (N

AS) S

igna

ling

TS 2

4.50

1

N2

Nex

t Gen

erat

ion

Appl

icat

ion

Prot

ocol

(NGA

P)TS

38.

413

N3,

Xn-

U, F

1-U

GPRS

Tun

nelin

g Pr

otoc

ol v

ersi

on 1

- Use

r Pla

ne

(GTP

v1-U

)TS

29.

281

Xn-C

Xn A

pplic

atio

n Pr

otoc

ol (X

nAP)

TS 3

8.42

3

Serv

ice

Base

d In

terfa

ces:

N**

*  (E

x: N

ausf

) Ap

plic

atio

n Pr

ogra

mm

ing

Inte

rface

s (A

PIs)

ba

sed

on H

yper

Tex

t Tra

nsfe

r Pro

toco

l (HT

TP)/2

pr

otoc

ol w

ith J

avas

crip

t Obj

ect N

otat

ion

(JSO

N)

IETF

RFC

754

0 fo

r HTT

P/2,

IETF

RFC

825

9 fo

r JS

ON, T

S 29

.5N

N fo

r NF

serv

ices

(Ex:

29.

500

Over

all S

BA, 2

9.50

2 SM

F, 29

.503

UDM

, 29.

518

AMF,

and

so o

n ba

sed

on th

e N

F)

5G N

ETW

ORK

ARCH

ITEC

TURE

ww

w.ro

hde-

schw

arz.c

om

IAB

-nod

e g

NB

Inte

gra

ted

ng

-eN

B

Inte

gra

ted

ng

-eN

B

Inte

gra

ted

gN

B

UE

UE

UE

UE

UE

LTE

Uu

NR

Uu

UE

NR

Uu

NR

Uu

UE

Bac

khau

l Lin

k (N

R U

u, F1

)

Bac

khau

l Lin

k (N

R U

u)

gNB

-CU

Xn

-U

gN

B-D

UgN

B-D

Ug

NB

-CU

-C

gN

B-C

U-U

IAB

-nod

e g

NB

IAB

-don

or g

NB

Xn

-C

N2

F1-C

F1-U

N3

E1

F1

Xn-C

and

Xn-

U

F1-UF1

-C

N2

N3

AMF

UPF

N2

N3

Acc

ess

Lin

k(N

R U

u)

Acc

ess

Lin

k(N

R U

u)

Mul

ti-RA

T Co

nnec

tivity

Over

all S

ervi

ce B

ased

Arc

hite

ctur

e (S

BA)

NG-

RAN

Arc

hite

ctur

e Disa

ggre

gate

d gN

B w

ith D

isag

greg

ated

gN

B-CU

Disa

ggre

gate

d gN

B

Stan

dalo

ne N

R w

ith th

e 5G

C (”

Optio

n 2”

)N

on-S

tand

alon

e N

R w

ith th

e EP

C (“

Optio

n 3/

3a/3

x”)

Optio

n 1:

E-U

TRA

with

EPC

(Bas

elin

e)

Optio

n 2:

Sta

ndal

one

NR

with

NGC

Optio

n 3,

3a,

3x:

Non

-Sta

ndal

one

NR

with

EPC

Optio

n 4,

4a:

Non

-Sta

ndal

one

E-UT

RA w

ith N

GC

Optio

n 5:

Sta

ndal

one

E-UT

RA w

ith N

GC

Optio

n 6:

Sta

ndal

one

NR

with

EPC

Optio

n 7,

7a,

7x:

Non

-Sta

ndal

one

NR

with

NGC

Optio

n 8,

8a:

Non

-Sta

ndal

one

E-UT

RA w

ith E

PC

AMF

UPF

UE

N3

N2

NR-

UugN

B

S-GW

MM

E

UE

NR-

UuS1

-U

S1-U

S1-M

ME

X2

LTE-

Uu

gNB

eNB

PCF

UDM

AF

AUSF

AMF

SMF

SCP

V-SE

PP/

H-SE

PP

Nns

sfN

nef

Nnr

fN

pcf

Nud

mN

af

Nns

saaf

Nau

sfN

amf

Nsm

f

NSS

FN

EFN

RF

NSS

AAF

N2

N3

N6

UPF

N1

NR-

U u

UE

NR-

Uu

Nee

ded

for e

ncha

nced

cap

abili

ty o

nly

Data

Net

wor

k (E

x: In

tern

et, I

MS,

Ente

rpris

e)

NG-

RAN

Over

all S

ervi

ce B

ased

Arc

hite

ctur

e3G

PP

has

defi

ned

a se

rvic

e-ba

sed

arch

itect

ure,

whe

re d

iffer

ent

Net

wor

k Fu

nctio

ns (N

Fs) p

rovi

de s

ervi

ces

via

serv

ice-

base

d in

terf

aces

. For

exa

mpl

e, o

ther

NFs

can

use

Nam

f in

terf

ace

to o

btai

n se

rvic

es o

f th

e A

MF.

Mul

ti-RA

T Co

nnec

tivity

A U

E m

ay c

onne

ct t

o m

ultip

le b

ase

stat

ions

(e.g

., eN

B a

nd g

NB

) sim

ulta

neou

sly.

Tw

o po

pula

r ne

twor

k ar

chite

ctur

es a

re S

tand

alon

e N

R w

ith t

he N

GC

(“O

ptio

n 2”

) and

Non

-Sta

ndal

one

NR

with

the

EP

C (E

N-D

C o

r O

ptio

n 3/

3a/3

x).

NG-

RAN

Arc

hite

ctur

eTh

e N

ext-

Gen

erat

ion

Rad

io A

cces

s N

etw

ork

(NG

-RA

N) c

onsi

sts

of N

R-b

ased

gN

Bs

and

LTE

-bas

ed n

g-e

NB

s. T

he N

G-R

AN

con

nect

s to

the

5G

C/N

GC

.

For m

ore

Info

rmat

ion