Internet of Things (IoT) Notes

Definition
The Internet of Things (IoT) is a dynamic global network infrastructure with self-
configuring capabilities that relies on standard and interoperable communication
protocols. In IoT:
• Physical and virtual "things" are equipped with unique identities, physical
attributes, and virtual personalities.
• These "things" use intelligent interfaces (e.g., sensors, actuators, embedded
systems) to connect and interact.
• They are seamlessly integrated into the information network, enabling smooth
communication and data exchange.
• IoT devices often collect, process, and share data related to users, their
activities, and their environment.
Key Characteristics in the Definition
1. Dynamic – Devices can adapt to changes in network conditions or requirements.
2. Global – IoT operates on a worldwide scale, connecting devices across
geographies.
3. Self-configuring – Devices can automatically connect, configure, and update
themselves without manual intervention.
4. Interoperable – Uses standard protocols so different devices from different
vendors can work together.
5. Physical & Virtual Integration – Bridges the gap between the physical world
(objects, sensors) and the virtual world (data, cloud services).

Characteristics of IoT
The Internet of Things (IoT) exhibits several key characteristics that define how it
functions and how devices interact in a connected ecosystem.
1. Connectivity
• Core Requirement: IoT devices must be connected to the infrastructure to
function.
 • Anytime, Anywhere: The network should support communication anytime,
anywhere.
• Importance: Without connectivity, the IoT concept has no value — devices must
remain online to exchange data.
2. Intelligence and Identity
• Intelligence: IoT systems must extract useful knowledge from raw data
generated by sensors.
• Data Interpretation: Proper data processing is essential for decision-making.
• Unique Identity: Each IoT device has a unique identifier (e.g., IP address, MAC
address) for tracking, querying, and managing devices.
3. Scalability
• IoT networks must support massive growth in the number of connected devices.
• The infrastructure should handle large-scale data generation and processing
efficiently.
4. Dynamic and Self-Adapting
• Devices should adapt automatically to changing conditions.
• Example: A surveillance camera adjusts to different lighting conditions
(day/night).
5. Self-Configuring
• Devices can connect, configure, and update themselves without manual
intervention.
• This feature supports rapid deployment and reduced maintenance effort.
6. Interoperability
• The architecture must allow different manufacturers’ devices to work together.
• Standard communication protocols are essential for smooth integration.
7. Safety and Privacy
• Data Security: Sensitive information must be protected from unauthorized
access.
• Device Security: Prevent unauthorized control or tampering of devices.
• User Privacy: Protect personal information and maintain confidentiality.

IoT Stack / Layers

IoT systems can be represented as a 7-layer stack, each layer handling a specific
function.

Layer Name Function

Provides specific services to the end user (e.g., smart

Layer 7 Application Layer
home apps, health monitoring dashboards).

User Experience Focuses on the interaction between the user and IoT
Layer 6
Layer system, ensuring ease of use and accessibility.

Session / Message Handles communication sessions and message

Layer 5
Layer exchanges (e.g., MQTT, CoAP protocols).

Deals with wireless communication technologies (e.g.,

Layer 4 RF Layer
Wi-Fi, Bluetooth, Zigbee, LoRa).

Hardware Interface Manages the interface between hardware modules and

Layer 3
Layer processing units.

Processing and
Layer 2 Processes collected data and triggers control actions.
Control Action Layer

Physical / Sensor Physical devices and sensors that collect data from the
Layer 1
Layer environment.

Challenges in IoT
IoT brings immense opportunities, but it also faces significant challenges that impact its
implementation, security, and efficiency.

1. Security & Personnel Safety

• Most critical challenge in IoT.
• With many devices connected in a network, a single compromised device can
potentially expose the entire system.
• User data vulnerability: Sensitive personal and business data can be stolen or
misused.
• Safety concerns: Devices like implants, health sensors, and industrial
controllers can put human safety at risk if hacked.
• Poor security design in devices can lead to large-scale cyberattacks.
 • Example: A hacked pacemaker or smart vehicle could cause life-threatening
situations.

2. Privacy
• Users can be tracked or monitored 24/7 due to continuous connectivity.
• Tracking may happen without the user’s knowledge or consent.
• Risk of profiling, surveillance, and misuse of personal activities.
• Privacy laws and encryption standards must be enforced to protect users.

3. Data Extraction from Complex Environments

• Sensors must be able to accurately collect data in varied and harsh
environments.
• Challenges include sensing temperature, humidity, vibration, or pressure during
transport or in remote areas.
• Example: Monitoring temperature-sensitive goods during shipping requires
robust sensors and stable network connectivity.

4. Connectivity
• Reliable wired or wireless connectivity is mandatory for IoT.
• Wireless technologies (Wi-Fi, Bluetooth, Zigbee, LoRa) rely on frequency bands
(e.g., 2.4 GHz), which may face congestion.
• Limited spectrum availability can lead to interference and slower data transfer.
• Rural areas may suffer from poor network infrastructure.

5. Power Requirements
• Most IoT devices are battery-operated, requiring energy-efficient operation.
• Battery life is a limitation, especially for remote or hard-to-reach devices.
• Growing device count increases total energy demand.
• Adoption of green energy sources (solar, wind) is encouraged for sustainable
IoT.
6. Complexity
• IoT is inherently multidisciplinary, involving hardware, software, networking,
data analytics, and domain-specific expertise.
• Rapid growth has led to a shortage of skilled professionals.
• Limited availability of toolkits, software frameworks, and hardware adds to the
difficulty.
• Integrating devices from different vendors increases complexity.

7. Storage
• IoT generates huge amounts of data that require efficient storage solutions.
• Cloud storage is becoming the standard, but decisions must be made:
o Which cloud provider to choose?
o Cost vs. capacity considerations.
o Security and compliance of stored data.
• In some cases, edge computing is preferred to process and store data closer to
the source to reduce latency.

Physical Design of IoT

1. "Things" in IoT
• In IoT, "things" usually refer to IoT devices with unique identities (e.g., IP
address, MAC address).
• They can perform remote sensing, actuating, and monitoring tasks.
Capabilities of IoT Devices:
1. Exchange data with other connected devices and applications (directly or
indirectly).
2. Collect and process data locally using onboard processors.
3. Send data to centralized servers or cloud-based back-ends for processing.
4. Perform some tasks locally and others within the IoT infrastructure depending
on time (temporal) and location (spatial) constraints.

Generic Block Diagram of an IoT Device

An IoT device typically includes multiple interfaces for wired and wireless
communication.
Key Components:
• I/O Interfaces for Sensors – Connect various sensors (temperature, motion,
light, etc.) to collect environmental data.
• Interfaces for Internet Connectivity – Wired (Ethernet) or wireless (Wi-Fi,
cellular, etc.).
• Memory and Storage Interfaces – Onboard storage (Flash, EEPROM) or external
storage for data buffering.
• Audio/Video Interfaces – For devices with media capabilities (e.g., surveillance
cameras, smart assistants).

Examples of IoT Devices

• Home Appliances – Smart refrigerators, washing machines, thermostats.
• Smartphones & Computers – Control hubs for IoT devices.
• Wearable Electronics – Fitness trackers, smartwatches.
• Automobiles – Connected cars, GPS systems.
• Energy Systems – Smart meters, solar panel monitoring.
• Retail Payment Systems – Contactless payment terminals.
• Printers – Network-enabled printing devices.
• Industrial Machines – Predictive maintenance sensors, factory automation.
 • Healthcare Systems – Remote patient monitoring devices.
• Surveillance Cameras – Smart security systems.

IoT Protocols
IoT communication follows protocol stacks, similar to traditional networking but
optimized for constrained devices.
a) Link Layer Protocols (Data transfer over physical medium)
• IEEE 802.3 – Ethernet: Wired LAN connectivity.
• IEEE 802.11 – Wi-Fi: Wireless LAN for high-speed data.
• IEEE 802.16 – WiMax: Long-range broadband wireless.
• IEEE 802.15.4 – LR-WPAN: Low-rate wireless personal area network (used in
Zigbee).
• 2G / 3G / 4G: Cellular network connectivity for wide-area communication.
b) Network / Internet Layer Protocols (Addressing & Routing)
• IPv4: Traditional IP addressing.
• IPv6: Extended addressing for a large number of devices.
• 6LoWPAN: IPv6 over Low-Power Wireless Personal Area Networks (efficient for
constrained devices).
c) Transport Layer Protocols (End-to-end communication)
• TCP (Transmission Control Protocol): Reliable, connection-oriented
communication.
• UDP (User Datagram Protocol): Faster, connectionless communication (used in
low-latency IoT apps).
d) Application Layer Protocols (Data formatting & exchange)
• HTTP (HyperText Transfer Protocol): Common web communication protocol.
• CoAP (Constrained Application Protocol): Lightweight protocol for constrained
devices.
• WebSocket: Full-duplex communication between client and server.
• MQTT (Message Queuing Telemetry Transport): Lightweight publish-subscribe
protocol for IoT.
• XMPP (Extensible Messaging and Presence Protocol): Messaging protocol
used for real-time communication.
Link Layer in IoT
Overview
• Function: Determines how data is physically sent over the network’s physical
medium (e.g., copper wire, coaxial cable, radio waves).
• Scope: Local network connection between hosts (devices) on the same link.
• Operation: Hosts on the same link exchange data packets using link layer
protocols.
• Responsibility: Defines coding and signaling methods for hardware devices to
send data over the medium.
1. IEEE 802.3 – Ethernet (Wired LAN)
• Definition: A collection of wired Ethernet standards for the link layer.
• Types & Mediums:
o 802.3 (10BASE5): Coaxial cable as shared medium.
o 802.3i (10BASE-T): Copper twisted-pair connections.
o 802.3j (10BASE-F): Fiber optic connections.
o 802.3ae: 10 Gbps Ethernet over fiber.
• Data Rates: From 10 Mb/s to 40 Gb/s+.
• Operation: Shared medium carries communication for all devices; data sent by
one device can be received by all others (depending on propagation and
transceiver capabilities).

2. IEEE 802.11 – Wi-Fi (Wireless LAN)

• Definition: Wireless Local Area Network (WLAN) standards.
• Frequency Bands & Types:
o 802.11a: 5 GHz band.
o 802.11b / 802.11g: 2.4 GHz band.
o 802.11n: 2.4 / 5 GHz bands.
o 802.11ac: 5 GHz band.
o 802.11ad: 60 GHz band.
• Data Rates: 1 Mb/s to 6.75 Gb/s.
• Usage in IoT: Provides wireless connectivity for devices within local networks
(e.g., smart home, offices).

3. IEEE 802.16 – WiMAX (Wireless Broadband)

• Definition: Wireless broadband access standards.
• Data Rates: 1.5 Mb/s to 1 Gb/s.
• Recent Update: 802.16m –
o 100 Mb/s for mobile stations.
o 1 Gb/s for fixed stations.
 • Usage in IoT: Suitable for wide-area IoT deployments requiring high-speed
wireless access (e.g., smart city infrastructure).

4. IEEE 802.15.4 – LR-WPAN (Low-Rate Wireless Personal Area Network)

• Definition: Standards for short-range, low-rate wireless communication.
• Data Rates: 40 Kb/s to 250 Kb/s.
• Power Efficiency: Designed for low-cost, low-speed communication in power-
constrained devices.
• Usage: Forms the basis for protocols like Zigbee, used in home automation and
sensor networks.

5. Mobile Communication (2G / 3G / 4G)

• Generations & Standards:
o 2G: GSM, CDMA — ~9.6 Kb/s.
o 3G: UMTS, CDMA2000 — higher speeds.
o 4G: LTE — up to 100 Mb/s.
• Usage in IoT: Enables devices to connect over cellular networks, especially
useful for mobile or remote IoT devices.

Network / Internet Layer in IoT

Overview
• Function: Sends IP datagrams from the source network to the destination
network.
• Responsibilities:
o Host addressing – Assigning unique addresses to devices.
o Packet routing – Determining the best path for packets across multiple
networks.
• Data Structure: The datagram contains:
o Source address – Identifies the sending device.
o Destination address – Identifies the receiving device.
• Addressing Scheme: Uses hierarchical IP addressing such as IPv4 or IPv6 for
host identification.
1. IPv4 (Internet Protocol Version 4)
• Definition: Most widely deployed version of the Internet Protocol.
• Addressing: 32-bit address scheme → total of 2³² = ~4.3 billion addresses.
• Format: Written in dotted decimal (e.g., 192.168.1.1).
• Limitation: Address exhaustion due to rapid growth of internet-connected
devices.
• Status: Being replaced gradually by IPv6.

2. IPv6 (Internet Protocol Version 6)

• Definition: Latest version of Internet Protocol, successor to IPv4.
• Addressing: 128-bit address scheme → 2¹²⁸ (~3.4 × 10³⁸) unique addresses.
• Format: Written in hexadecimal colon-separated form (e.g.,
2001:0db8:85a3::8a2e:0370:7334).
• Advantages over IPv4:
o Vastly larger address space.
o Better security features (IPSec is mandatory).
o Improved routing efficiency.

3. 6LoWPAN (IPv6 over Low-Power Wireless Personal Area Networks)

• Purpose: Brings IPv6 to low-power devices with limited processing capability.
• Frequency: Operates in the 2.4 GHz range.
• Data Rate: Up to 250 Kb/s.
• Compatibility: Works with IEEE 802.15.4 link layer protocol.
• Special Feature: Uses compression mechanisms to efficiently transmit IPv6
datagrams over low-bandwidth, low-power networks.
• Use Case: Ideal for wireless sensor networks in smart homes, healthcare
monitoring, and industrial IoT.
Transport Layer
The Transport Layer protocols provide end-to-end message transfer capability that is
independent of the underlying network.
Message transfer can be:
• Connection-oriented using a handshake (e.g., TCP)
• Connectionless without handshake or acknowledgements (e.g., UDP)
This layer is responsible for:
• Error control – detecting and correcting transmission errors
• Segmentation – breaking messages into smaller units for transmission
• Flow control – ensuring the sender does not overwhelm the receiver
• Congestion control – preventing excessive data flow that could slow or crash
the network

TCP (Transmission Control Protocol)

TCP is the most widely used transport layer protocol, used by:
• Web browsers (with HTTP, HTTPS)
• Email programs (SMTP)
• File transfer applications (FTP)
Characteristics:
• Connection-oriented and stateful
• Ensures reliable transmission of packets in the correct order
• Provides error detection, discarding duplicates and retransmitting lost packets
• Flow control prevents the sender from overwhelming the receiver
• Congestion control avoids network congestion and performance degradation

UDP (User Datagram Protocol)

UDP is a connectionless transport protocol that does not require a setup handshake.
Best suited for:
• Time-sensitive applications
• Small, quick data exchanges
• Scenarios where low latency is more important than reliability
Characteristics:
• Transaction-oriented and stateless
• Does not guarantee delivery, packet ordering, or duplicate elimination
• Has minimal overhead compared to TCP

Application Layer
The Application Layer defines how an application interacts with lower-layer protocols
to send data over a network.
Key functions:
• Encodes application data (e.g., files) before transport
• Uses port numbers for application addressing
• Enables process-to-process communication via ports
• Works closely with the Transport Layer (e.g., TCP, UDP)

HTTP (HyperText Transfer Protocol)

• Foundation of the World Wide Web
• Request–Response Model: Client sends a request → Server responds
 • Commands (methods): GET, PUT, POST, DELETE, HEAD, TRACE, OPTIONS
• Stateless – each request is independent
• Identifies resources using URIs (Uniform Resource Identifiers)
• Clients can be browsers, IoT applications, mobile apps, etc.

CoAP (Constrained Application Protocol)

• Designed for Machine-to-Machine (M2M) communication in constrained
environments (low power, low bandwidth)
• Similar to HTTP, but runs over UDP instead of TCP
• Client–Server architecture using connectionless datagrams
• Easily interfaces with HTTP
• Supports methods: GET, PUT, POST, DELETE
WebSocket
• Enables full-duplex communication over a single TCP connection
• Allows continuous message exchange between client and server without
reopening the connection
• Clients can be browsers, mobile apps, or IoT devices
• Ideal for real-time applications (e.g., live data updates, chat systems)
MQTT (Message Queue Telemetry Transport)
• Lightweight publish–subscribe protocol
• Client–Server architecture:
o Clients (e.g., IoT devices) publish messages to topics on a broker
o Broker forwards messages to clients subscribed to those topics
• Well-suited for low-power devices and low-bandwidth networks
• Commonly used in IoT sensor networks
XMPP (Extensible Messaging and Presence Protocol)
• Real-time communication and XML data streaming between network entities
• Applications: messaging, presence, data syndication, multiplayer gaming, group
chat, voice/video calls
• Decentralized with client–server and server–server communication
 • Allows IoT devices to exchange real-time messages efficiently

DDS (Data Distribution Service)

Definition:
DDS is a data-centric middleware standard designed for device-to-device or
machine-to-machine communication. It uses a publish–subscribe model for efficient
and scalable data exchange.
Key Concepts:
• Publisher: Object responsible for distributing data.
• Subscriber: Object responsible for receiving data.
• Topic: Named channel for data exchange; publishers write to it, subscribers read
from it.
• QoS Control: Provides configurable reliability, delivery guarantees, and
performance tuning.

DDS Middleware
• Middleware is the software layer between the operating system and
applications in a distributed system.
• Purpose:
o Facilitates communication between system components.
o Handles data transmission, routing, and synchronization.
o Allows developers to focus on application logic rather than low-level data
exchange mechanics.
Data-Centricity in DDS
• DDS enables QoS-controlled data sharing between applications.
• Communication happens through publish–subscribe on Topics identified by a
Topic name.
• Subscriptions can apply:
o Time filters – receive data at controlled intervals.
o Content filters – receive only relevant subsets of data.
• DDS Domains are completely independent; no data sharing occurs across
domains.
AMQP (Advanced Message Queuing Protocol)
Definition:
An open application-layer protocol designed for business messaging with reliable
queuing and routing features.
Communication Models:
• Point-to-Point – One sender to one receiver.
• Publish–Subscribe – Multiple subscribers receive published messages.
How It Works:
1. Publisher sends a message to an Exchange.
2. Exchange routes the message to one or more Queues based on routing rules.
3. Consumers receive messages from queues for processing.
Advantages:
• Reliable message delivery.
• Supports complex routing patterns.
• Works well for asynchronous, distributed applications.
Logical Design of IoT
The Logical Design of an IoT system is an abstract representation of entities and
processes. It focuses on what the system does rather than how it is implemented
physically.

Key Components of Logical Design

• IoT Functional Blocks
• IoT Communication Models
 • IoT Communication APIs

1. IoT Functional Blocks

An IoT system is composed of several functional blocks that together provide
capabilities such as identification, sensing, actuation, communication, and
management.

Device Block
• Comprises IoT devices responsible for:
o Sensing environmental parameters.
o Actuating physical elements.
o Monitoring system parameters.
o Controlling devices remotely or locally.

Services Block
• Provides various IoT services such as:
o Device Monitoring Services – tracking device status and health.
o Device Control Services – remotely controlling actuators and sensors.
o Data Publishing Services – sharing collected data with other systems or
applications.
o Device Discovery Services – finding and registering new devices
dynamically within the network.

Communication Block
• Manages data exchange between devices and systems.
• Ensures reliable and efficient communication using appropriate protocols and
models.

Application Block
• Provides the user interface for interaction with the IoT system.
• Allows users to:
 o Control devices and actuators.
o Monitor real-time system status.
o View and analyze processed data and reports.

Management Block
• Offers functions to govern the IoT system:
o Configuration management.
o Network management.
o Fault management.
o Performance monitoring.

Security Block
• Ensures the security of the IoT system by providing:
o Authentication – verifying user/device identities.
o Authorization – controlling access to resources.
o Message and Content Integrity – ensuring data is not altered during
transmission.
o Data Security – encrypting data to prevent unauthorized access.
IoT Communication Models
There are several communication models used in IoT systems to exchange data
efficiently between devices, servers, and applications. The main models are:
• Request-Response
• Publish-Subscribe
• Push-Pull
• Exclusive Pair

1. Request-Response Communication Model

• The client sends a request to the server.
• The server processes the request by fetching data or resource representations.
• The server then sends a response back to the client.
• Used in protocols like HTTP, where clients ask for data and servers respond
accordingly.

2. Publish-Subscribe Communication Model

• Involves three main entities:
o Publishers: Source of data that send messages to topics.
o Brokers: Manage topics and handle message distribution.
o Consumers: Subscribe to topics to receive messages.
 • Publishers are unaware of consumers; communication is decoupled.
• When a broker receives data for a topic, it forwards it to all subscribed
consumers.
• Widely used in IoT messaging protocols like MQTT and DDS.

3. Push-Pull Communication Model

• Producers (pushers) send data to queues without knowing who the consumers
are.
• Consumers (pullers) pull data from queues when ready.
• Queues act as buffers, helping to handle mismatches in production and
consumption rates.
• Provides decoupling between producers and consumers, improving reliability
and scalability.
4. Exclusive Pair Communication Model
• A bidirectional, full-duplex communication model.
• Establishes a persistent connection between client and server.
• Connection remains open until explicitly closed by the client.
• Both client and server can send messages independently after connection
setup.
• Used in protocols like WebSocket for real-time communication.

3. IoT Communication APIs

REST-based Communication APIs

• REST (Representational State Transfer) is an architectural style for designing
web services and APIs that focus on system resources and how resource states
are addressed and transferred.
• REST APIs follow the Request-Response communication model.
• The REST architectural constraints include:
o Client-Server: Separation of concerns between client and server.
o Stateless: Each request contains all information to process it; no client
context is stored on the server.
 o Cacheable: Responses must define themselves as cacheable or not.
o Layered System: Architecture composed of hierarchical layers.
o Uniform Interface: Standardized way to interact with resources (e.g.,
using HTTP methods).
o Code on Demand (optional): Servers can send executable code to
clients.
• A RESTful web service is a web API implemented using HTTP and follows REST
principles.

WebSocket-based Communication APIs

• WebSocket APIs provide bi-directional, full-duplex communication between
clients and servers.
• Follows the Exclusive Pair communication model with a persistent connection.
• Enables real-time, low-latency data exchange between connected entities.
Comparison: REST vs WebSocket

Characteristics REST WebSocket

Stateless: Each request Stateful: Server maintains open

Nature
independent connections

Uni-directional (request →
Direction Bi-directional (full duplex)
response)

Communication
Request-Response Full Duplex
Model

New TCP connection per

TCP Connection Single persistent TCP connection
request

HTTP headers in every request

Minimal overhead after initial
Header Overhead → overhead, less suited for real-
handshake
time

Vertical scaling easier; horizontal

Easier to scale horizontally and
Scalability scaling harder due to state
vertically (stateless)
maintenance
IoT Levels & Deployment Templates
An IoT system is composed of multiple levels/components working together to enable
sensing, processing, communication, and control.

1. Device Level
• IoT Device:
o Enables identification, remote sensing, actuation, and monitoring.
o Physical hardware with sensors, actuators, and communication modules.

2. Resource Level
• Resources:
o Software components on the IoT device responsible for:
▪ Accessing sensor data.
▪ Processing and storing sensor information locally.
▪ Controlling actuators.
▪ Enabling network access for communication with other systems.

3. Controller Service Level

• Controller Service:
o Native service running on the IoT device.
o Acts as an intermediary between the device and external web services.
o Sends sensor data from the device to web services.
o Receives commands from applications via web services to control the
device.

4. Database Level
• Database:
o Stores the data generated by IoT devices.
o Can be local (on-premises) or cloud-based.
 o Supports efficient data retrieval and long-term storage.

5. Web Service Level

• Web Services:
o Link between IoT devices, applications, databases, and analytics.
o Implemented using either:
▪ HTTP and REST principles (RESTful services).
▪ WebSocket protocol (for real-time, full-duplex communication).

6. Analysis Component Level

• Analysis Component:
o Processes and analyzes the raw IoT data.
o Converts data into meaningful results, trends, or alerts.
o Provides insights that are easy for users to understand and act upon.

7. Application Level
• Application:
o User interface to interact with the IoT system.
o Enables users to:
▪ Monitor system status.
▪ Control devices remotely.
▪ View analyzed data and reports.

IoT Levels Explanation

IoT Level 1
• Description:
o Single node/device handles:
▪ Sensing and/or actuation
 ▪ Data storage locally
▪ Data analysis locally
▪ Hosts the application locally
• Use Case:
o Suitable for low-cost, low-complexity systems.
o Data size is small, and analysis requirements are minimal or simple.
• Example:
o Home Automation System – e.g., a smart light or thermostat that senses
and acts locally without cloud dependency.

IoT Level 2
• Description:
o Single node/device performs sensing and/or actuation plus local
analysis.
o Data storage happens on the cloud.
o Application is usually cloud-based for access anywhere.
• Use Case:
o Suitable where data volume is large, but primary analysis is not
computationally heavy and can be done locally.
• Example:
o Smart Irrigation system – sensor node analyzes soil moisture locally but
stores and manages data remotely on the cloud.

IoT Level 3
• Description:
o Single node/device performs sensing and/or actuation.
o Data is stored and analyzed fully in the cloud.
o Application is cloud-based.
• Use Case:
o Suitable for large data volumes with computationally intensive
analysis that cannot be handled locally.
 • Example:
o Tracking Package Handling – devices collect data, but all processing and
analysis are cloud-based for complex insights.

IoT Level 4
• Description:
o Multiple nodes perform local analysis.
o Data is stored in the cloud.
o Application is cloud-based.
o Contains local and cloud-based observer nodes that subscribe to and
receive information collected in the cloud from IoT devices.
• Use Case:
o Suitable where multiple nodes are needed, handling large data volumes
with computationally intensive analysis.
• Example:
o Noise Monitoring system with many distributed sensors analyzing locally
and reporting to cloud for further processing.

IoT Level 5
• Description:
o Multiple end nodes perform sensing and/or actuation.
o A coordinator node collects data from end nodes and sends it to the
cloud.
o Data storage, analysis, and application are all cloud-based.
• Use Case:
o Suitable for wireless sensor network (WSN)-based systems with large
data and heavy analysis needs.
• Example:
o Forest Fire Detection system with many sensor nodes coordinated by a
central node sending data to the cloud for analysis and alerting.

IoT Level 6
 • Description:
o Multiple independent end nodes perform sensing/actuation and send
data directly to the cloud.
o Data storage and analysis happen in the cloud.
o A centralized controller monitors the status of all end nodes and sends
control commands.
o Results are visualized via cloud-based applications.
• Use Case:
o Suitable for distributed systems requiring centralized management and
cloud analytics.
• Example:
o Weather Monitoring System with many independent sensors reporting
weather data to the cloud for analysis and visualization.

Machine-to-Machine (M2M)
• Definition: Direct communication between machines/devices for remote
monitoring, control, and data exchange.
• M2M Area Network:
o Composed of M2M nodes with embedded sensing, actuation, and
communication hardware.
o Uses local communication protocols: ZigBee, Bluetooth, ModBus, M-
Bus, Wireless M-Bus, PLC, 6LoWPAN, IEEE 802.15.4, etc.
o These protocols connect nodes locally within the area network.
• Communication Network:
o Connects remote M2M area networks.
o Can be wired or wireless, typically IP-based.
o M2M area networks may use non-IP protocols, but long-distance
connectivity uses IP protocols.
M2M Gateway
• Purpose: Allows communication between non-IP-based M2M nodes and
external IP-based networks.
• Function:
o Translates between proprietary/non-IP protocols in the M2M area
network and IP-based protocols in the wider communication network.
o Enables inter-network data exchange between remote M2M systems.

IoT vs M2M – Key Differences

Aspect M2M (Machine-to-Machine) IoT (Internet of Things)
Communication Proprietary or non-IP based Standard IP-based
Protocols protocols within area networks; protocols; focus on above
focus on below network layer network layer protocols
protocols. (e.g., HTTP, MQTT).
Devices Homogeneous machines in a Diverse “things” with
closed network. unique IDs, sensing,
actuation, and cloud
connectivity.
Emphasis Hardware-centric, embedded Software-centric, cloud
modules for apps, analytics, and AI.
sensing/communication.
Data Collection Stored on-premises in point Stored in cloud (public,
solutions. private, or hybrid).
Applications Accessed by local/on-premises Accessed by cloud-based
apps. apps.
Scope Limited to specific use cases Broad ecosystem —
(industrial automation, telemetry, consumer, industrial,
remote monitoring). healthcare, transport, etc.
Connectivity Can work without internet (e.g., Primarily internet-enabled
GSM, GPRS, CDMA). communication.
Data Sharing Shared only between the two Shared across multiple
communicating machines. platforms and
applications.
Intelligence Limited intelligence; hardware- Embedded intelligence;
focused. interacts with other
systems for decision-
making.
Examples ATMs, vending machines, industrial Smart homes, wearables,
telemetry. connected cars, smart
cities.