Lecture 5 - SDN in 5G

Question 1

What’s the difference between 5G standalone and non-standalone?

Answer 1

Standalone:
- Control & Data go through a 5G-basestation (RAN)
- From RAN to a 5G-Core
- 5G-Core to internet

Non-Standalone
- Data comes from a 5G-Basestation (RAN)
- Control & Data from a 4G-Basestation (RAN), yes data from both
- Information goes from RANs to a 4G-Code (“new frequencies, old architecture and protocols”)
- From 4G-Core to internet

Question 2

What kind of architecture does 5G standalone architecture use within the control plane?

Answer 2

• Service Based Architecture (SBA)
• Check slide 9 in “SDN in 5G” slides for full architecture

Question 3

What kinds of network functions exist in 5G and what are they used for?

Answer 3

RAN (Radio Access Network)
- NOT part of the 5G Core
- Provides a “tunnel over the air”
— Encryption, baseband+HF modulation,…

AMF (Access and Mobility Management Function)
- Control plane interface to RAN
- Coordinates authentication + session setup of connecting UEs

SMF (Session Management Function)
- Upon request of AMF: flow rule installation in the data plane

UPF (User Plane Function)
- Terminates GTP Tunnel from RAN (N3 interface)
- Flow rules for each UE

Question 4

Explain the PFCP protocol and what “PFCP” Stands for.

Answer 4

Packet Forwarding Control Protocol (PFCP)
- Used in 4G/5G networks to control the data/user plane (UPF)
- Similar to OpenFlow
- Used for:
— Tunnel creation
— IPv4, IPv6, Ethernet tunnels possible
— Tunneling protocol (in 4G/5G): GTP (GPRS Tunneling Protocol)

Question 5

When getting a legal frequency range in Germany, who assigns the frequency? What’s the possible spectrum? What’s the required information?

Answer 5

Assigned by Bundesnetzagentur
Possible spectrum:
- 3.7 - 3.8 GHz
- 23.25 - 27.5 GHz (mmWave)

Required info:
- Area
- Requested frequency range
- Time (max 10 years)
- Building info
- Sending power
- …