5G-CONNECTED EDGE CLOUD

5G-C ONNECTED E DGE C LOUD

Larry Peterson, Princeton & ONF Oguz Sunay, ONF Nate Foster, Cornell Sachin Katti, Stanford Nick McKeown, Stanford Jennifer Rexford, Princeton

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T ^UTORIAL P ^LAN

Deconstruct 5G

• Emphasize Concepts over Acronyms

• Relate to Internet Counterparts

• Identify Open Source Building Blocks

Provide an End-to-end Perspective

• Up and Down the Software Stack

• From Research to Real-World Deployment

Discuss Research Opportunities

• Ongoing in the Slack channel – #sigcomm-2021-tutorial-5gcloud

• Open the floor during the last 30-45 minutes

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M ^OBILE C ^ELLULAR N ^ETWORK

…

…

Access Network

• Tens-of-Thousands of Cell Towers

• Thousands of Aggregation Points

»Often called Central Offices

»Anchor Wired & Wireless Nets

Internet (Backbone)

H ISTORY OF THE M ^OBILE N ^ETWORK

Parallels the 40-year history of the Internet

• First two generations introduced Voice and Text service

• 3G introduced Broadband Data Service (hundreds of kilobits-per-second)

• 4G improved Broadband Data rates (few megabits-per-second)

• 5G will improve data rates, but promises much more…

Largely opaque to many Internet/Cloud developers

• 3GPP is the primary standardization body

• Release 15 demarks transition from 4G to 5G

•

Each generation defines a 10-year evolutionary path

•

Implementations are closed, proprietary, and bundled

5G G ^OALS

Enhanced Mobile Broadband

• Extreme aggregate capacity (10 Tbps per square kilometer)

• Extreme data rates (multi-Gbps peak, 100+ Mbps sustained)

Massive Internet-of-Things

• Ultra-low energy (10+ years of battery life)

• Ultra-low complexity (10s of bits-per-second)

• Ultra-high density (1 million nodes per square kilometer)

Mission-Critical Control

• Ultra-low latency (as low as 1 ms)

• Ultra-high availability (meet latency goal 99.999% of the time)

• Extreme mobility (up to 100 km/h)

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E DGE C LOUD Functionality is moving from Datacenters to the Edge

• Close proximity to end users and their devices

• Enables new applications

• Augmented Reality (AR) / Virtual Reality (VR) / Immersive UIs

• Internet-of-Things (IoT) / Autonomous Vehicles / Coordinated Robots

• Buzzword to Know: Industry 4.0

Where is the Edge?

• Central Offices that implement the Access Network are one possibility

• Combination of “on-prem” and “in the cloud” is another

5G is leveraging best practices in building scalable clouds

• Bare-metal servers and switches

• Cloud native (microservice-based) software

• Agile engineering practices (DevOps)

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Sensors

Surveillance IoT

Multimedia

Employees

Visitors

Small Cell (CBRS)

Small Cell (CBRS)

Small Cell (CBRS)

Enterprise Edge

Edge Apps

Control and Management Platform

Enterprise Control Portal

Distributed Data Plane provides local breakout at

every remote Edge site

Central Cloud

Central Apps

5G-ENABLED ENTERPRISE EDGE CLOUD

Data Plane5G

5GControl Plane

M ^ORE I ^NFORMATION

Research Position Papers

• Deep Programmability: SIGCOMM CCR, Oct 2020.

• Democratizing the Edge: SIGCOMM CCR, Apr 2019.

Project Web Sites

• P^RONTO: https://prontoproject.org

ØIncludes links to demo videos

• AETHER: https://aetherproject.org

ØIncludes links to SD-Fabric, SD-RAN, and SD-Core projects

Background Reading Material

• https://5G.systemsapproach.org

• https://SDN.systemsapproach.org

5G-C ONNECTED E DGE C LOUD

Introduction

Basics of 5G Architecture Radio Transmission RAN Internals 5G x SDN

Open Source Edge Cloud Research Opportunities 9

M ^OBILE C ^ELLULAR N ^ETWORK

…

…

Access Network

• Tens-of-Thousands of Cell Towers

• Thousands of Aggregation Points

»Often called Central Offices

»Anchor Wired & Wireless Nets

Internet (Backbone)

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Cellular Access Network

eNB UEs

eNB UEs

eNB

UEs

Mobile Core

Radio Access Network

Backhaul Network

M ^OBILE N ^ETWORK = RAN + M ^OBILE C ^ORE

Mobile Core

• Provides IP connectivity

• Ensures QoS promises are met

• Tracks usage for billing

• Tracks mobility

Terminology

• UE = User Equipment

• eNB = 4G Base Station

• gNB = 5G Base Station

• EPC = 4G Mobile Core

• NG-Core = 5G Mobile Core

Internet (Backbone)

Mobile Core Control Plane Base Station

Mobile Core User Plane

CUPS: C ^ONTROL /U ^SER P ^LANE S ^EPARATION

RANUser Plane ControlRAN Plane

CoreUser Plane ControlCore Plane

4G/5G Mobile Cellular

Network

Mobile Core User Plane Mobile Core Control Plane Base Station

UE

B ^ASE S ^TATIONS : D ^ETECT A ^CTIVE UE ^S

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Mobile Core User Plane Mobile Core Control Plane Base Station

UE

B ^ASE S ^TATIONS : ^SET U ^P C ^ONTROL P ^LANE

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Mobile Core User Plane Mobile Core Control Plane Base Station

Voice Traffic

Streaming Multimedia Traffic UE

B ^ASE S ^TATIONS : S ^ET U ^P U ^SER P ^LANE

Mobile Core User Plane Mobile Core Control Plane Base Station

UE

GTP + UDP over IP Physical Layer

Packets Transmitted Using Analog Modulation

SCTP over IP

B ^ASE S ^TATIONS : T ^UNNEL O ^VER IP

Mobile Core User Plane Mobile Core Control Plane Base Station

UE

B ^ASE S ^TATIONS : H ^ANDOVER

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Mobile Core User Plane Mobile Core Control Plane Base Station

UE

B ^ASE S ^TATIONS : L ^INK A ^GGREGATION & L ^OAD B ^ALANCING

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Mobile Core Base Station

UPF

User Plane Control Plane SDSF UDSF

PCF NRF NEF

NSSF UDM

MobilityAMF SMF

Session AUSF

Auth

5G M ^OBILE C ^ORE (NG-CORE)

Microservice Building Blocks

Internet (Backbone)

Core-UP Core-CP

Base Station UE

Secure Private Network (3a) (3c) (3b)

(1)

(2)

(4)

SCTP/IP GTP/UDP/IP

E ^STABLISH S ^ECURE CP/UP C ^HANNELS

SIM

(1) UE connects over an open channel (2) Core-CP authenticates UE (3) Core-CP sets up user plane channel (4) User plane channel established

5G-C ONNECTED E DGE C LOUD

Introduction

Basics of 5G Architecture Radio Transmission RAN Internals 5G x SDN

Open Source Edge Cloud Research Opportunities 21

M ^ULTIPATH S ^IGNAL P ^ROPAGATION

CQI = Channel Quality Index

Sent from devices to base stations every 1ms

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F ^OUNDATION

Coding

• Insert extra bits into the message to improve the ability to recover the original data

• e.g., Turbo Codes

Digital Modulation

• Vary the base signal (amplitude, frequency, phase) to encode the message

• e.g., Quadrature Amplitude Modulation (16-QAM, 64-QAM)

Multiplexing

• Share the available radio spectrum

•

e.g., TDMA (2G), CDMA (3G), OFDMA (4G, 5G)

Coding Digital

Modulation

RF Modulation Pulse

Shaping

OFDMA = Orthogonal Frequency Division Multiple Access

Time (Symbols)

Frequency

Df = 15kHz PRB

12 subcarriers

= 180 kHz

1 OFDMA Symbol Resource Element Transmission Time Interval (TTI) = 1ms

PRB

F ^ROM M ULTIPLEXING TO S ^CHEDULING

Scheduler Requested QCI (subscriber assigned) Reported CQI

(from devices)

Select segments to transmit from a set of subscriber queues

Allocate Resource Blocks

S CHEDULING R ESOURCE B LOCKS

QCI = QoS Class Index Resource Type

Guaranteed Bit Rate (GBR) Delay-Critical GBR Non-GBR

Delay Budget, Error Rate, Max Burst…

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5G N ^EW R ^ADIO (NR)

4G permits one waveform, with numerology presented on the earlier diagram

• Waveform = Frequency, Amplitude, Phase-shift independent property of the signal

For sub-1GHz bands, 5G allows 50MHz bandwidths with two waveforms

• 15kHz subcarrier spacing / 0.5ms scheduling intervals

• 30kHz subcarrier spacing / 0.25ms scheduling intervals

For 1-6GHz bands, 5G allows up to 100MHz bandwidths with three waveforms

• 15kHz subcarrier spacing / 0.5ms scheduling intervals

• 30kHz subcarrier spacing / 0.25ms scheduling intervals

• 60kHz subcarrier spacing / 0.125ms scheduling intervals

For mmWave bands, 5G allows up to 400MHz bandwidths with two waveforms

• 60kHz subcarrier spacing / 0.125ms scheduling intervals

• 120Hz subcarrier spacing / 0.125ms scheduling intervals

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5G NR: A Q UALITATIVELY B ^ETTER R ^ADIO

Dynamically change the waveform to achieve better channel utilization Super-wide bandwidths enable high throughput with line-of-sight coverage Shorter scheduling intervals makes latency more predictable

• Important for mission-critical applications

Narrow bandwidths set aside for simplified air interface

• Important for massive numbers of low-power IoT devices

5G-C ONNECTED E DGE C LOUD

Introduction

Basics of 5G Architecture Radio Transmission RAN Internals 5G x SDN

Open Source Edge Cloud

Research Opportunities

RF Front End D/A

Conversion MAC PHY

PDCP Mobile Core RRC

Control Plane

Mobile Core User Plane

control

RLC

Scheduling

R ^AN P ^IPELINE

RRC (Radio Resource Control) – Configures coarse-grain and policy-related aspects of the pipeline.

PDCP (Packet Data Convergence Protocol) – Header compression, integrity, early forwarding decision.

RLC (Radio Link Control) – Segmentation/reassembly, reliable transmission (ARQ).

MAC (Media Access Control) – Schedules/multiplexes segments, late forwarding decision.

PHY (Physical Layer) – Coding and modulation.

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RF Front End D/A

Conversion MAC PHY

PDCP Mobile Core RRC

Control Plane

Mobile Core User Plane

control

RLC

Scheduling

Other Base Stations (for Handover, Link Aggregation, and

Load Balancing)

Other Carrier Frequencies (for Multi-Carrier

Transmissions)

R ^AN P ^IPELINE

(Historically, the entire pipeline runs in the base station.)

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RF Front End D/A

Conversion MAC PHY

PDCP Mobile Core RRC

Control Plane

Mobile Core User Plane

control

RLC

Scheduling

S ^PLIT RAN

Central Unit

(CU) Distributed Unit

(DU) Radio Unit

(RU)

CU has Control & User Plane elements

• CU-C

• CU-U

DU must be within 1ms of RUs

• Same Cell Tower

• Same campus, manufacturing plant

RU

RU RU

RU RU RU

RU RU

DU DU DU DU

CU

S ^PLIT RAN

RF Front End D/A

Conversion MAC PHY

PDCP RLC

Scheduling Real Time RAN Control Mobile Core

Control Plane

Mobile Core User Plane

Near-Real Time RAN Control (RRC)

Control Signals To/From Mobile Devices

S ^OFTWARE -D ^EFINED RAN

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RF Front End D/A

Conversion MAC PHY

PDCP RLC

Scheduling

Mobile Core Control Plane

Mobile Core User Plane

Near-Real Time RAN Intelligent Controller (RIC)

Control Signals To/From Mobile Devices

Control Plane (Forwarding)

RRC

SD-RAN

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Near Real-Time RAN Intelligent Controller (RIC) Load Balancing Interference Management Link AggregationControl Cipher Key Assignment Semi-Persistent Scheduling

Base Station Real Time Control (MAC Scheduler)

RAN Slicing

Handover Control

R-NIB: Device Config, Session Info R-NIB: Time Averaged CQI Values

R-NIB: Instantaneous CQI Values

…

RF Configuration

SD-RAN

Control Apps

Network OS

To Other RAN Pipeline Stages

Y ^OU A ^RE H ^ERE

UserRAN Plane ControlRAN Plane

CoreUser Plane ControlCore

Plane

CU-URAN CU-CRAN

CoreUser Plane ControlCore Plane DU

RU

CU-CRAN ControlCore

Plane DU

RU

CU-UData ControlCU-U

Core-U Data Core-U Control RIC

App App App

(Next: How to Implement UPF) UPF (Later)

Mobile Core Base Station

UPF

User Plane Control Plane SDSF UDSF NRF

PCF NEF

NSSF UDM

AMF

Mobility SMF

Session

AUSF Auth

U ^SER P ^LANE F ^UNCTION

Internet (Backbone)

GTP / UDP / IP

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P4-B ^ASED U ^SER P ^LANE

UPF

Server vSwitch

smartNIC NIC

Internet

Softw are

Hardw are

Programmable Switch

HW Path SW Path

Buffering

GTP Termination HQoS

Radio Unit

Ctrl Agent

…Control Plane…

(See Robert MacDavid’s paper at SOSR ‘21)

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