4. At the heart of the IoT revolution lies the IoT protocol
stack, a hierarchical structure that facilitates data exchange
and communication across different layers. This white paper
aims to provide a comprehensive overview of the IoT
protocol stack, detailing each layer’s functions, protocols,
and significance.
The IoT Protocol Stack
The IoT protocol stack can be mapped to the seven-
layer OSI (Open Systems Interconnection) model, which is
widely used to understand and design network architectures.
Each layer in the IoT protocol stack has specific roles and
protocols that ensure efficient and reliable communication
between IoT devices and systems.
5. 1. Physical Layer
Function: The physical layer is responsible for the physical
connection of devices to the network. It handles the
transmission of raw data between devices and physical
transmission media, converting digital information into
electrical, radio, or optical signals.
Protocols/Technologies:
Wi-Fi: Wi-Fi is one of the most commonly used wireless
protocols for IoT devices, especially for applications in smart
homes, industrial environments, and consumer electronics. It
provides high-speed data transfer and range but consumes
more power.
6. Bluetooth: is widely used for short-range communication in
IoT systems, such as wearable devices, health monitors, and
smart home applications. Good for high-speed data transfer,
Bluetooth sends both voice and data signals up to 10 meters.
BLE is energy-efficient, making it ideal for battery-powered
devices.
ZigBee: Low-power, low-data-rate wireless communication.
An IEEE 802.15.4-based specification for a suite of high-
level communication protocols used to create personal area
networks with small, low-power digital radios.Zigbee and Z-
Wave are popular protocols for home automation and smart
sensors that use mesh networking to increase range and
reliability. Zigbee devices are often used in smart home hubs,
lighting, and security systems.
7. LTE: Long-term evolution for mobile communication.
NB-IoT: Narrowband IoT for low-power wide-area
networks.
LoRaWAN:(Long Range Wide Area Network) is designed
for long-range, low-power communication in applications
like smart agriculture, asset tracking,
and environmental monitoring. It offers a much greater
range than Wi-Fi or Bluetooth, but with lower data rates.i.e
Long-range, low-power wireless communication. Long-
range wide-area networks (LoRaWANs) connect mobile,
secure, bi-directional battery-operated devices.
8. NFC
A set of communication protocols for communication
between two electronic devices over a distance of 4 cm
(1 ⁄2 in) or less. NFC offers a low-speed connection with
simple setup that can be used to bootstrap more-capable
wireless connections.
The near field communication (NFC) protocol is used for
very small range communication (up to 4 cm), such as
holding an NFC card or tag next to a reader. NFC is often
used for payment systems, but also useful for check-in
systems and smart labels in asset tracking.
9. RFID:
RFID stands for Radio Frequency Identification.
RFID tags store identifiers and data. The tags are attached to
devices and read by an RFID reader. The typical range of
RFID is less than a meter. RFID tags can be active, passive,
or assisted passive. Passive tags are ideal for devices without
batteries, as the ID is passively read by the reader.
Active tags periodically broadcast their ID, while
assisted passive tags become active when RFID reader is
present. Dash7 is a communication protocol that uses active
RFID that is designed to be used within Industrial IoT
applications for secure long-range communication. Similar to
NFC, a typical use case for RFID is tracking inventory items
within retail and industrial IoT applications.
10. Cellular (4G/5G):
Cellular networks, particularly 4G and 5G, are useful
for IoT systems that require wide-area coverage, such as fleet
management or remote sensors in rural areas.
11. 2. Data Link Layer
Function: This layer ensures reliable data transfer across
the physical link. It handles error detection and correction,
flow control, and the establishment and termination of
connections between devices.
Protocols/Technologies:
Ethernet: A common wired networking technology.
PPP (Point-to-Point Protocol): Used for direct
communication between two network nodes.
IEEE 802.15.4: A standard for low-rate wireless personal
area networks, used in ZigBee.
12. 3. Network Layer
Function: The network layer is responsible for routing data
packets from the source to the destination across multiple
networks. It handles logical addressing, traffic directing, and
congestion control.
Protocols/Technologies:
IP (Internet Protocol): The primary protocol for routing
data across networks.
RPL(Routing Protocol for Low-Power and Lossy
Networks): Designed for low-power and lossy networks.
6LoWPAN (IPv6 over Low-Power Wireless Personal
Area Networks): An adaptation layer for IPv6 over IEEE
802.15.4.
13. ARP (Address Resolution Protocol)
ARP stands for Address Resolution Protocol. ARP is used to
convert the logical address ie. IP address into physical
address ie. MAC address. While communicating with other
nodes,
RARP
RARP stands for Reverse Address Resolution Protocol.
RARP works opposite of ARP. Reverse Address Resolution
Protocol is used to convert MAC address ie. physical address
into IP address ie. logical address.
14. ICMP
ICMP stands for Internet Control Message Protocol. ICMP is
a part of IP protocol suite. ICMP is an error reporting and
network diagnostic protocol. Feedback in the network is
reported to the designated host. Meanwhile, if any kind of
error occur it is then reported to ICMP.
IGMP
IGMP stands for Internet Group Message Protocol. IGMP is
a multicasting communication protocol. It utilizes the
resources efficiently while broadcasting the messages and
data packets. IGMP is also a protocol used by TCP/IP.
15. 4. Transport Layer
Function: This layer ensures end-to-end communication
and data transfer reliability. It manages error correction,
flow control, and data segmentation and reassembly.
Protocols/Technologies:
TCP (Transmission Control Protocol): Provides
reliable, ordered, and error-checked delivery of data.
UDP (User Datagram Protocol): Offers a simpler,
connectionless communication model with minimal
overhead.
16. 5. Session Layer
Function: The session layer manages sessions or
connections between applications. It establishes,
maintains, and terminates communication sessions.
Protocols/Technologies:
MQTT (Message Queuing Telemetry Transport): A
lightweight messaging protocol for small sensors and
mobile devices.
CoAP (Constrained Application Protocol): Designed
for use with constrained nodes and networks.
AMQP (Advanced Message Queuing Protocol): Used
for transactional messages between servers.
XMPP (Extensible Messaging and Presence Protocol):
A communication protocol for message-oriented
middleware.
17. 6. Presentation Layer
Function: This layer translates data between the application
layer and the network. It handles data encryption,
compression, and translation.
Protocols/Technologies:
JSON (JavaScript Object Notation): A lightweight data
interchange format.
XML (eXtensible Markup Language): A markup
language for encoding documents.
Data Encryption Standards: Various standards for
securing data.
18. 7. Application Layer
Function: The application layer provides network services
directly to end-user applications. It defines protocols for
specific data exchange and communication needs.
Protocols/Technologies:
HTTP (HyperText Transfer Protocol): The foundation of
data communication for the World Wide Web.
MQTT(Message Queue Telemetry Transport Protocol
): Also used at the application layer for lightweight messaging.
CoAP(Constrained Application Protocol): Also used at the
application layer for constrained environments.
DDS (Data Distribution Service): A middleware protocol for
data-centric connectivity.
OPC UA (Open Platform Communications Unified
Architecture): A machine-to-machine communication
protocol for industrial automation.
19. Conclusion
The IoT protocol stack is a complex but essential
framework that enables the seamless communication and
data exchange necessary for IoT systems to function
effectively. Understanding the roles and protocols at each
layer helps in designing robust, efficient, and scalable IoT
solutions. As the IoT landscape continues to evolve,
staying informed about the latest developments in IoT
protocols and standards will be crucial for leveraging the
full potential of IoT technologies.
