This document discusses IoT protocols for data communication and connection models. It describes the key pillars of IoT protocols as being device, connectivity, data, and analytics. It also outlines various types of IoT data protocols like AMQP, DDS, XMPP, and WebSocket that establish end-to-end communication. Additionally, it covers IoT network protocols like Bluetooth, LPWANs, ZigBee, Z-Wave and others that facilitate secured communication between IoT devices over the internet.

1. IoT Protocols: Making IoT Data Communication Seamless
• The protocols of the Internet of Things (IoT) technology stack
are essential as, without them, the hardware would be rendered
useless, and data communication would be a challenge.

2. IoT protocols by definition and vision
• IoT protocols aim to connect devices to IoT devices over a
seamless and secure connection.
• The IoT protocols operate on four pillars - device, connectivity,
data, and analytics.
• Their defense-in-depth security strategy shields the data
transmission layer by layer.
• While the business layer includes the management of billing
and data marketplaces, the people who interact with IoT
devices and technologies fall under the technology users layer.
• The device layer comprises a combination of sensors,
hardware, actuators, software, and gateways, constituting a
device that connects and interacts with a network.
• The data layer involves the data collected, processed, stored,
and analyzed in business contexts.

3. IoT protocols connection models
• There is no set pattern for data routing, and the communication
is highly dependent on the network topology.
• However, the fundamental models are used either as standalone
or in combinations for IoT deployments, including:

4. 1. Device-to-device
• It enables communication between nearby devices (proximity)
using IoT Protocols like Bluetooth, ZigBee, Z-Wave, 4G, 5G,
and WiFi.
2. Device-to-gateway
• In this model, the devices communicate with the data system
using a mediator platform, such as LPWAN, WiFi, and/or
Ethernet IoT protocols.
• The core functions of device-to-gateway are combining data
from sensors, analyzing it, and routing it to the destination data
system (data center or cloud). Also, in case of any problem, the
connection model sends back the data to the source device.

5. 3. Device-to-data
• It works on edge computing, allowing devices to connect
directly with the data source. A few popular device-to-data
connection models include BLE, LoRaWAN, and Z-Wave.
4. Gateway-to-data
• It is the simple communication between the mediator platform
or central hubs and the data center or cloud. Open Automation
Software (OAS) and Universal Data Connector are the best
examples of robust IoT Gateways.
5. Communication between data
• This protocol connection model allows data transmission
between the data center and the cloud. It includes IoT Data
protocols like MQTT, HTTP, REST, etc.

6. Types of IoT protocols
• IoT protocols and standards are broadly classified into two
separate categories, including IoT data protocols that have
presentation or application layers and network protocols for IoT
comprising datalink and physical layers:

7. 1. IoT Data Protocols
• These protocols establish the end-to-end communication
between low-power IoT devices and the hardware at the source,
client, and/or user side, using only wired or cellular networks.
The IoT data protocols function without an internet connection:
1. Advanced Message Queuing Protocol (AMQP)
• AMQP is widely used in banking and finance as a message-
oriented open standard software protocol. It comprises three
crucial message components - Exchange, Queue, and Routing.
• It is based on the Transmission Control Protocol and works on
the architecture of "publish/subscribe" and "request/response"
types. In addition, the guaranteed delivery or transaction
message makes AMQP interoperable, secure, and reliable.

8. 2. Data Distribution Service (DDS)
• DDS is a UDP based "publish/subscribe" API that facilitates
secure real-time M2M data sharing between the connected IoT
devices. Furthermore, it works on broker-less scalable
architecture (DCPS and DLRL), i.e., it operates independently
of any hardware or software platform.
• Its multi-purpose function simplifies IoT deployment for both
small devices and high-performance networks.
3. Extensible Messaging and Presence Protocol (XMPP)
• XMPP is a decentralized, open-source, and secure protocol
developed using XML language to enable real-time data
exchange.
• It operates as a presence indicator by reflecting the status of
available servers and devices. XMPP-IoT is a lightweight
version of XMPP and is the best for consumer-oriented IoT
deployments as it is extensible, scalable, and flexible.

9. 4. WebSocket
• Introduced by HTML5, WebSocket is an event-triggered independent TCP-based IoT
protocol or API. It establishes full-duplex real-time communication between the
client and server.
• Using advanced technology streamlines complexities involved in the bi-directional
transmission over the internet. And, it is suitable to maintain constant connectivity
across heterogeneous IoT devices. Notably, WebSocket is much faster than HTTP
5. Open Platform Communications Unified Architecture (OPC UA)
• OPC UA is a next-generation data model technology ideal for Industry 4.0 and IoT. It
operates on a platform-independent, encrypted, and extensible multi-layered
architecture. In addition, its service-oriented framework supports both
"publish/subscribe" and "request/response" models.
• As per the latest press release published by OPC Foundation, leading IoT vendors
such as SIEMENS, SAP, Microsoft, IBM, AWS, and Google Cloud are already
leveraging OPC UA for edge-to-cloud applications.

10. II. IoT Network Protocols
• These protocols constitute specific standards, policies, and
unified rules to establish secured communication between IoT
devices over the internet.
• With emerging advancements in the IoT ecosystem, these
protocols utilize multiple technologies that work on network
topologies. The most widely used are star and mesh topologies.
Following are the extensively used IoT network protocols:
• 1. Bluetooth and BLE
• Bluetooth is the top choice for shorter-range wireless
communication, preferably for personal 2.4 GHz networks.
Bluetooth Low Energy (BLE) is its optimized version and the
standard protocol for IoT architecture.
• The latest version of Bluetooth is 5.3. It was released on 13th
July 2021 and is still in beta. Bluetooth best suits beacons,
fitness, automotive, retail, and audio IoT applications.

11. 2. Cellular - 4G and 5G
• Cellular is a wireless mobile communication network technology that
facilitates large bandwidth and reliable broadband services.
• Currently, 3G is almost on the verge of extinction. On the other hand,
4G is leading but not suited for IoT applications due to higher cost
and power consumption.
• However, the new-age 5G is ideal for IoT applications across
industries and personal usage.
3. Wi-Fi and Wi-Fi HaLow
• WiFi is the most popular and conventional wireless network
protocol for home and commercial usage. But, it is not very
flexible and scalable for IoT purposes.
• WiFi HaLow (IEEE 802.11 ah) is a unique solution to overcome
its challenges. This high-level communication protocol provides
a long-range between 750 and 950 MHz with low-power
connectivity.

12. • 4. Low Power Wide Area Networks (LPWANs)
• LPWANs are a new set of wireless network protocols devised
to set up communication between low-power IoT applications
over long ranges.
• They are a cost-saving option because they operate on small
and affordable batteries that are long-lasting and power-
efficient.
• MIOTY, LoRaWAN, 6LoWPAN, Thread, NB-IoT, LTE-M,
SigFox, and HayStack are purpose-built LPWANs for large-
scale IoT deployments.

13. 5. ZigBee
• ZigBee is a mesh wireless communication protocol that
operates on a 2.4 GHz network.
• It is short-range, highly interoperable, low-power consuming,
and facilitates massive data transfer in a single instance with
high security.
• ZigBee is most appropriate for small, and medium ranged IoT
devices such as microcontrollers, sensors, gateways, and so on.
• Notably, due to its mesh grid structural design, the connectivity
can be extended over a long distance using multi-hop routing.
• ZigBee is best suited for commercial building and innovative
home automation applications.
• Actually, it is the safest wireless protocol for transferring real-
time patient data from a sensor.

14. 6. Z-Wave
• Similar to ZigBee, the Z-Wave protocol also works on mesh
network topology. However, it is most prominent for IoT home
automation applications.
• Z-Wave is a Radio Frequency (RF) based, less power-
consuming wireless communication technology that operates on
800-900 MHz and is purely location-dependent.
• As a result, it hardly faces any connectivity hindrance. It
facilitates safe and steady data transmission with low latency.

15. 7. Extensible Messaging and Presence Protocol (XMPP)
• This technology dates back to the early 2000s and was designed for
real-time human-to-human communication. XMPP is now used for
M2M communication and for routing XML data.
• XMPP supports the real-time exchange of structured but extensible
data across multiple network entities, making it suitable for
consumer-oriented IoT deployments, such as smart appliances and
wearables.
• Other than the above-stated options, the network protocols such as
Lightweight M2M (LWM2M), Radio-frequency Identification
(RFID), Near Field Communication (NFC), Ethernet, and Wi-Sun
have contributed significantly towards setting up the sustainable
connection in the IoT space.
• Therefore, be it for home or commercial usage, the selection of an
ideal IoT network protocol must consider the parameters of
bandwidth, range, power consumption, latency, intermittent
connectivity, Quality of Service (QoS), and security.

16. • Benefits of IoT wireless protocols
• IoT protocols form a crucial component of the IoT infrastructure.
They serve higher data throughput with lesser complexities.
Wireless IoT protocols have become the first choice solution for
personal and industrial usage. The rising demand for wireless
IoT protocols is because of the core benefits:
• Affordability
• Less time and energy consumption
• Robust security and data privacy
• Good network coverage and connectivity
• Automated and streamlined communications
• Faster data transfer and smoother operations
• Easy setup and deployment in the IoT infrastructure
• Simple to use while resulting in enhanced productivity

17. IoT Protocol Layers
• IoT works on various networking technologies based on the IT
infrastructure requirements, and therefore, it needs architecture
to establish a coherent IoT ecosystem.
•

18. • Considering the complexities involved in the configuration,
operations, functionalities, and communications, the five
layers of IoT architecture are best suited for all purposes.
• 1. Network layer
• Its core function is to connect the IoT devices with the network
systems and servers. The network layer also helps to route and
control the data transmission with the help of set
communication protocols and unified formats.
• Utilizing the TCP/IP stack and cellular and wireless
technologies depending on the specification, the network layer
helps set up secure transmission across all interconnected
devices. A few examples are IPv4/IPv6, ICMP, IGMP, ARP,
3G/4G/5G, UDP, 6LoWPAN, and WiFi.

19. • 2. Application layer
• It acts as an interface between the IoT devices and the end users
or any other device that requests the information over the
secured network. After successful data processing, formatting,
and presentation, it produces the final information. A few
examples of the application layer are HTTP, FTP, POP, IMAP,
TLS, SMTP, DNS, TFTP, SNMP, and TELNET.
• The IoT application protocol depends on four crucial parameters
- latency, reliability, bandwidth, and transportation. Considering
the same, along with the correspondence of the specifications
and features, the following are the top five IoT application
protocols:
• Representational State Transfer (REST)
• Constrained Application Protocol (CoAP)
• Advanced Message Queuing Protocol (AMQP)
• Message Queue Telemetry Transport (MQTT)
• Extensible Message and Presence Protocol (XMPP)

20. • 3. Perception layer
• It constitutes sensors, actuators, and AI-powered devices to
gather valuable details about the surrounding physical objects
or the environment. The accumulated data is converted from
analog signals to digital format for further operations.
• Its functioning includes identification, information collection,
and automated control technologies to channel the digital and
real worlds. A few examples of the perception layer include
surveillance cameras, bar codes, portable PCs, RFID, WSN,
and GPS.

21. • 4. Security layer
• It minimizes the risk of potential cyberattacks on the most
vulnerable areas of the IoT ecosystem. The security
checkpoints occur at three significant places - the device
(including hardware and software), cloud, and connection.
• With the rapid digital evolution during the outbreak, the
security challenges and underlying threats to the IoT
architecture also grew exponentially. Therefore, the layered
security approach has become of utmost importance in the
ongoing scenario.
• A few examples of the security layer include Trusted Platform
Module (TPM) chips, multiple authorizations, firewalls, NAC,
AAA, NAP, IPS encryption, and cryptography mechanisms.

22. • 5. Edge layer
• It works on the edge computing framework to improve latency,
bandwidth, and real-time communication challenges. The edge layer's
primary goal is to fetch and process the requested information closer
to the data sources.
• With the ever-increasing number of smart devices over a centralized
cloud system, the 'delay in response' is a significant concern. However,
combined with 5G and AI capabilities, edge IoT layers perform
exceptionally well for time-sensitive data and deliver faster results.
• A few examples of the edge layer include electronic vehicles,
smartphones, smartwatches, laptops, security cameras, V2X, public
transit applications, smart cities, and green technologies. The five
layers of IoT architecture facilitate the smooth functioning of the IoT
ecosystem.
• Besides, they can accommodate expansions and handle intricacies
following the latest technological advancements. The goal is to
establish seamless IoT interoperability, taking care of the 3Cs -
change, compatibility, and cybersecurity.

23. CONCLUSION
• It should be noted that safe and effective device
management is the keystone to the sustainable development
and management of IoT networks worldwide.
• The communication, data sharing, and usage of information by
intelligent devices happen in a full-stack IoT ecosystem.
• A unified global protocol standardization thus becomes crucial
to eliminate IoT fragmentation and potential security threats.

24. Conti…
• IoT protocols are the medium of communication or a shared
language that helps establish connections between different
smart devices and helps them interact with each other.
• They are essential for holistic device management.
• IoT protocols consider the needs, communication, and security
of the various devices integrated.
• Depending upon the IoT architecture, present scenario, and
usage context, different IoT protocols are designed to
minimize the risk of intrusion.