How SDNs bring Versatility to 5G Networks

Babu Narayanan K J

Chief Technologist

Centre of Excellence in Wireless technology, IIT Madras (CEWiT)

ICSDN 2019

What do we cover

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•5G Networks – a short intro

• SDN concepts in 5G – RAN, Core, Management

• Flexibilities of 5G network enabled by SDN

• SDN based Indigenous 5G Test bed

Basic 5G network

3

Core NetworkAccess NetworkDevices & User Equipments

gNodeB

RAN Cloud

Edge Cloud

5G Network Functions

Virtualized 5G

4

UE Data Network

VM/Container

Computing Storage Networking

5G CoreNG RAN

Centralised Unit

Distributed Unit

Virtualised InfraDistributed Unit

Distributed Unit

SDN concepts for 5G networks

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• Separation of Control plane from User/Data plane• Control nodes for connectivity and Data nodes for traffic

• Logically centralized network controller handles allocation and routing of traffic through data plane network elements

• System-wide view of the network to enable centralized control

• Keep UP standardized while the CP manages the variability

SDN in Core Networks

Control Plane

User Plane

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UE NG RANUser Plane Function

(UPF)

Data Network

VM/Container

Computing Storage Networking

Control Plane Functions • Access and Mobility Management,

Authorization• Session management, Routing

policies and rules

SDN in 5G Core 5G Core

Control Plane

User Plane

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UE NG RANUser Plane Function

(UPF)

Data Network

VM/Container

Computing Storage Networking

5G Core

Service Based Architecture

Service Based ArchitectureVirtual Network

Functions

What SDN in Core brings to 5G• Flexible architectures and topologies – selecting and locating

CP and UP resources independently

• Independent evolution of the CP and UP functions

• Ex. When throughput is to be increased, add/scale UP nodes

• Reducing Latency on application service

• Selecting User plane nodes closer to RAN

• Advanced analytics using AI/ML tools in CP, executions in the UP

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Enabling Mobile Edge Computing

UE NG RAN UPFN6

Data Network

N4

UPFN6

SMF

N9

N9

10

AMF

5GC CP Functions

UPF

N4N4

Mobile Edge Platform

AppApps

Data Network -1

Data Network -1

• Low latency

• Real time access to RAN

• High bandwidth

• Location info

N3

Routing influenced by Application Functions

UE NG RAN UPF1N6

Data Network

N4

UPF2N6

Data Network

SMF

N3

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N4

AMF NEF

AF (Int) • User Traffic routing decisions influenced by AF

• Trusted AF or External AF

• Application Mobility: Application locations can change

N3

PCF

AF (ext)

Flexible architectures

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CU-UP

CU-CP

DU

DU

DU

Cloud Infra

UEs

MEC Platform

Cloud Infra

Edge Cloud

Central Cloud

UPF

SMF SMF

UPF

Data Network

Data Network

Virtual network Functions

APP

UPFUPF

Data Network

UPF Local Data

Network

CU-UPCU-UP

SDN in Radio Access Networks

SDN in 5G RAN

Centralised Unit – Control Plane

Distributed Unit

Centralised Unit – User

Plane

E1

F1-C

F1-U

Centralised Unit – User

Plane

Distributed Unit

Distributed Unit

Radio Units (with PHY low)

• gNB-CU-CP selects the gNB-CU-UP(s) for the requested services

• RAN cloud better enabled by SDN. Control centralised, Data distributed

• Very tight coupling of CP / UP in RAN. Full separation is complex

5G Core - CP 5G Core - UP

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RAN Controller

UE

Configurability in 5G RAN

E1

F1-CF1-U

PDCP-C

RRC

PDCP-U

SDAP

PDCP-U

SDAP

MAC

PHY-High

MAC

RLC

PHY-High

MAC

PHY-High

CU-CP CU-UP

Radio Units (with PHY low)

5G Core - CP 5G Core - UP

CU-UP

RLC RLCRLC RLCRLC

DU DU DU

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• The individual modules like RLC, PDCP etc are configured as per the User Plane requirements

• Ex. What features for URLLC traffic vis-à-vis eMBB traffic

UE

Configurability in 5G RAN

UE

PDCP-C

RRC

PDCP-U

SDAP

PDCP-U

SDAP

MAC

PHY-High

MAC

RLC

PHY-High

MAC

PHY-High

CU-CP CU-UP

Radio Units (with PHY low)

5G Core - CP 5G Core - UP

CU-UP

RLC RLCRLC RLCRLC

DU DU DU

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• Data Radio Bearers carry the User Plane traffic

• The bearers are configured to meet the QoS and Slice requirements

Examples of what SDN brings to RAN

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• Independent scaling of data functions• Signalling loads v/s data loads

Ex. Large number of devices with low throughputs (IOT) v/s small number of devices with high throughputs (eMBB)

• Latency reduction

• Leveraging Multiple Radio Access Types (NR, WiFi, DSL)

• Cell densification• Managing users in large number of cells spread over a smaller area

• RAN Cloud

• Optimum use of resources, power etc

SDN along with NFV enabling two major end to end features of 5G –

Slicing and Orchestration

Network Slicing in 5G Networks

PDCP SDAP

PDCP SDAP

MAC RLCPHY

RLC

PDCP SDAP

MAC

RLC

PHY

SMF UPFIOT

service

eMBBService

URLLC Service

SMF UPF

SMF UPF

Slicing help in creating and dynamically managing virtual end to end networks over a common infrastructure

• Dynamic service chaining using SDN & NFV to support features like URLLC

• Flexible placement of network elements and optimize their interactions19

Transport CoreRadio Access

Orchestration in 5G Networks

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Automatically programming the network - the hardware and the software that makes it up, to create and manage the services

Infrastructure

RAN -Low

VNFVNF

PNF

PNFPNF

Network Infrastructure

RAN-High Transport Core

End to end Orchestrator

IP/ Optical

PNF

VNF VNF

VNF

Orchestrator

Domain Controllers

Network Functions

Virtual Infrastructure

(NFVI, VIM)

Orchestration in 5G Networks

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• Centralised controllers get overall state of the network

• Multiple SDN controllers to orchestrate the network - multiple levels, multiple domains

• SDN control - Connectivity among VNFs and PNFs (NFVI) and Control & configuration of the VNFs

Automatically programming the network - the hardware and the software that makes it up, to create and manage the services

Infrastructure

RAN -Low

VNFVNF

PNF

PNFPNF

Network Infrastructure

RAN-High Transport Core

End to end Orchestrator

IP/ Optical

PNF

VNF VNF

VNF

Orchestrator

Domain Controllers

Network Functions

Virtual Infrastructure

(NFVI, VIM)

Synergy of AI and Data analytics with SDN/NFV

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• Network Intelligence• Software defined networking allows the distribution of network intelligence

including edge

• Service creation and Traffic routing can use big data analytics

• Automated and Self healing networks • AI and Data Analytics hugely enhance operational automation of 5G networks

• Decide where to scale specific network functions and application services -Based on machine learning algorithms that analyze network utilization and traffic data patterns

• AI and ML monitor the behaviour of the network, detect events and provide suitable solutions

• Decisions are implemented automatically by the orchestration platform

SDN based End to end 5G Test Bed

Building End to End Indigenous 5G Test Bed –

IITMIITB IITH

IISc

IITD

IITK

Along With

Several Industry Partners

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A Collaborative Project by:

Test Bed Outcomes and their uses

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Hardware and Software IPs

(Hardware platforms, Prototypes, ASICs, Stacks)

Start-ups, SMEs, Tech companies

End to end Test Bed

Industry - Start-ups, SMEs,

Technology Institutes - research and teaching

Algorithms & Techniques

(Implementation IPs, patents)

R&D organisations, Product Companies, Research teams –

Academia & Industry

Expertise

5G Ecosystem in India, especially product and service companies

5G Test Bed Project

End to end 5G Indigenous Test Bed

UE

oreAMF

UPF

NRF

AUSF UDM NSSF

SMF

UDR

External Network

IMS

AF

PCF

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Basic Telecom management and Orchestration layer

NEF N1, N2

N3

WiFi Interworking

Non-3GPP (WiFi)

Fronthaul

Backhaul

RAN Emulator

Base Station (gNodeB) 5G Core

NR

eCPRI

RRH

RF mmWave

RF sub6GHzBaseBand

L2/L3

User Device

Thank You

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