IoT overview

IoT basics

• Internet of things
• Extends Internet connectivity beyond standard devices to everyday objects
• Usually uses IPv6 due to the limited number of IPv4 addresses
• Operating systems: Linux or Windows (10) IoT

Top-level components

• Device
  • Includes hardware and software that directly interact with the world.
  • They connect to a network to communicate with each other, or to centralized applications
• Gateway
  • Enables services to reach cloud services.
  • Infrastructure component providing security and protocol translations
  • Also used as a service that process data on behalf of group or cluster devices.
  • Often a device e.g. smart home hub.
  • Usually from the same vendor
• Cloud
  • See cloud computing
• Sensors
  • Detects, measures or indicates any specific physical quantity
  • E.g. light, heat, motion, moisture, pressure, or similar entities
  • Converts them into any other form which is mostly, electrical pulses.

IoT communication models

Device-To-Device (D2D)

• Direct communication between devices
• Uses a medium such as Bluetooth Low Energy etc.
• Common in home automation systems e.g. light bulbs or wearables e.g. smart watch and heart monitor.
• Simpler security
• E.g. Vehicle-to-vehicle (V2V)
  • Uses Vehicle Ad Hoc Network (VANET)
    • Based on MANET i.e. decentralized wireless network (without routers)

Device-To-Cloud (D2C)

• IoT device directly communicating with the cloud server
• Often uses ethernet or WiFi
• Lets the user (and an application) to obtain remote access to a device
• E.g. smart card for dogs, remote monitoring
• Two credentials:
  • the network access credentials (such as the mobile device's SIM card)
  • credentials for cloud access
• E.g. Nest Learning Thermostat

Device-To-Gateway (DTG)

• IoT devices basically connect to an intermediary device to access a cloud service
• Often includes an application software operating on a local gateway device (like a smartphone or a "hub")
• Gateway provides security, protocol translation and usually does aggregation
• E.g. Samsung SmartThing ecosystem

Back-end data-sharing

• Extends device-to-cloud model
• Access are granted to the uploaded data to third-parties
• E.g. Map My Fitness that compiles data from other applications

Layered architecture

• IoT architecture can be categorized into different layers.
• There's no consistency regarding naming of layer.
  • Different methodologies are used but the concepts they represent are very similar.
• 📝 It usually consists of 5 layers:
  1. Edge technology layer the "IoT objects collecting data"
  2. Access gateway layer the "data transporter"
  3. Internet layer the "endpoint connector"
  4. Middleware layer the "data analyzer and processor"
  5. Application layer the "user interface"
• Some sources also name sixth layer: 6. Business layer the "core logic"
• Each layer is utilized by layer below without knowledge of other layers
• 
• Read more: IoT Elements, Layered Architectures and Security Issues: A Comprehensive Survey

Five-layers of IoT architecture

Edge technology layer

• Also known as perception layer or hardware layer
• Physical objects (hardware components)
  • Covers IoT capable devices
  • E.g. sensors, actuators, heat sensor, RFID tags, readers, device itself
• Connects devices within network and server
• Gathers environment data
• Key security components
  • Encryption and key agreement
  • Sensor data protection
• Vulnerabilities
  • Eavesdropping: real time attack to intercept privacy communications.
  • Node Capture: capturing a key node such as gateway to reveal information.
  • Fake Node and Malicious: adding node to input fake data to stop transmitting real information
  • Replay (play back) attack: eavesdrops a communication and reusing it to authenticate.
  • Timing Attack: Extract secrets by observing respond time

Access gateway layer

• Also known as network layer or transport layer
• Handles data transmission i.e. transferring the data through network
• E.g. Wi-Fi, bluetooth
• Enables communication
  • Connects two endpoints e.g. a clients with a device.
  • Includes the initial data handling.
  • Through e.g. message routing, message identification, and subscriptions.
• Key security components
  • Encryption
  • Identity authentication
• Vulnerabilities
  • Denial of Service (DoS) Attack with redundant requests
  • Main-in-The-Middle (MiTM) Attack: to intercept and manipulate data in real-time
  • Storage Attack: Changing data stored in device or cloud
  • Exploit attack: Exploits vulnerabilities in an application, system or hardware

Internet layer

• Responsible for end-points connectivity.
• Carries out communication between two endpoints.
  • E.g. device-to-device, device-to-cloud, device-to-gateway and back-end data-sharing.

Middleware layer

• Also known as processing layer
• Responsible for device and information management.
• Handles data analytics
  • I.e. storing, processing and analysis of data.
  • E.g. data analysis, data aggregation, data filtering, device information discovery, and access control.
• Behaves as interface for two-way communication between
  • Application layer (the user interface).
  • Edge technology layer (the hardware).
• Key security components
  • Key security layer, secure cloud computing, antivirus
• Vulnerabilities
  • Exhaustion: Can disturb memory, battery e.g. after effect of a DoS
  • Malware

Application layer

• The user interface for
  • Graphic data representation
  • Controlling, managing and commanding IoT devices.
• Responsible for delivering service and data to users.
  • A service is application-specific e.g. industrial, manufacturing, automobile, security, healthcare...
• Key security components
  • Authentication
  • Key agreement
• Vulnerabilities
  • Cross site scripting: injecting code through e.g. JavaScript
  • Malicious code attack: can activate itself or require user attention to perform an action.
  • Dealing with Mass Data
    • Caused by massive amount of data transmission
    • Can lead to data loss and network disturbance

Other IoT layers

Business layer

• Includes business models
• System management
• Key security components
  • Privacy protection
• Vulnerabilities
  • Business logic attack: exploits a programming flaw
  • Zero-day attack: exploits security hole unknown to the vendor

IoT connectivity

Wireless IoT connectivity

Approx. range up to	Connectivity	Speed
10 cm	NFC	424 kbit/s
1 m	RFID	300 tags per second
10 m	Li-Fi	100 gbit/s
60 m	Bluetooth low energi (BLE)	1 or 2 mbit/s
100 m	WiFi	1300 mbit/s
1 km	Wi-Fi HaLow	78 mbit/s
2 km	5G	20 gbit/s
30 km	LTE-Advanced	300 mbit/s
70 km	Celullar	- (depends on 4g etc.)
1000 km	LPWAN	200 kbit/s
World-wide	VSAT	16 mbit/s

Short-range wireless communication

• Bluetooth Low Energy (BLE)
  • Newer versions of bluetooth (after 4.0)
  • Optimized for battery usage.
• Wi-Fi
  • Wireless network protocol using radio waves.
  • Wi-Fi 6 specification standard (2020) is the latest standard (x6 faster).
• Radio-Frequency Identification (RFID)
  • Data storage tag that can be attached to an item for tracking
  • Passive tag has range up to 1m while active tags can go up to 100m.
  • Used in e.g. passports, credit cards.
• Li-Fi (Light-Fidelity)
  • Similar to Wi-Fi, but using visible light for communication
• Near-Field Communication (NFC)
  • Based on a radio frequency (RF)
  • Used e.g. in phones, payment cards
  • Must either either physically touch or be in a few centimeters of each other.

Medium-Range Wireless Communication

• LTE-Advanced: Formally submitted as a candidate 4G, often being described as 3.9G.
• Wi-Fi HaLow: low power, long-range, also known as "WiFi for Internet of Things"
• 5G: Introduced in 2019, highest with minimum of 10 Gbps

Long Range Wireless Communication

• Low-Power Wild-Area Network (LPWAN)
  • Long range communication (up to 10 km) at a low bit rate
• (VSAT) Very Small Aperture Terminal
  • World-wide satellite communication technology uses small dish antennas
• Cellular using e.g. radio towers to spread e.g. 4G, 5G..

Wired IoT connectivity

• Ethernet (cat 6 up to 10 Gbps speed)
• Power-Line Communication (PLC) : using electrical wiring to carry power and data, around 200 Mbit/s.