Iot SPPU Unit 4 PptA9 Unit 4 IoT (2).ppt

Dr. D. Y. Patil Institute of Technology
217529- Internet of Things
Unit Number: 4
Unit Name: IOT Systems, Network and Protocols
Unit Outcomes: CO4
Analyze trade-offs in interconnected wireless embedded device networks.
Select Appropriate protocols for IoT Solutions.

Syllabus
 Study of RF Wireless Sensors, Wireless networks;
 Wireless Sensor Networking (WSN),
 Cellular Machine-to- Machine (M2M) application networks,
 Computer Connected to Internet,
 Network Devices; Device configuration and management,
 Exchange information in real time without human intervention, IoT Protocols

 A computer network can be described as a system of interconnected devices that can communicate using
some common standards called the Internet protocol suite or TCP/IP. These devices communicate to
exchange network resources, such as files and printers, and network services.
 Here is an example of a computer network consisting of two computers connected together:
 The example above shows that the two computers are directly connected
using a cable. This small network can exchange data between just these
two computers.
 What if we want to expand our network? Then we can use network devices
such as routers, switches, or hubs, to connect two or more computers
together:
What is Network

 Listed below are the most common types of computer networks:
 Local Area Network (LAN) – LANs are commonly used in small to medium size companies,
households, buildings, etc., with limited space.
 Personal Area Network (PAN) – PAN covers a short distance of 10 meters. Bluetooth is an example of
PAN.
 Metropolitan Area Network (MAN) – MANs are used in a single geographic region, such as a city or
town.
 Wide Area Network (WAN) – WANs cover larger areas like different states and countries.
 Wireless Local Area Network (WLAN) – Wireless LAN is used for wireless networks, connecting wired
and wireless devices.
Types of Computer Networks

 A wireless network is a computer network that uses
wireless data connections between network nodes.
 Wireless networking is a method by which
homes, telecommunications networks and business
installations avoid the costly process of introducing
cables into a building, or as a connection between various
equipment locations.
 Admin telecommunications networks are generally
implemented and administered using radio
communication. This implementation takes place at the
physical level (layer) of the OSI model network structure.
 Examples of wireless networks include cell phone
networks, wireless local area networks (WLANs),
wireless sensor networks, satellite communication
networks, and terrestrial microwave networks.
Wireless Networking..

 Wireless Local Area Networks (LAN): A wireless local-area network (WLAN) is a group of collocated computers or
other devices that form a network based on radio transmissions rather than wired connections. A Wi-Fi network is a type
of WLAN
 Wireless Personal Area Networks (PAN):WPAN is PAN (Personal Area Network) where the interconnected devices are
centered around a person’s workspace and connected through wireless medium. That’s why it is also called as Person’s
centered short range wireless connectivity. Typically the range is within about 10 meters means very short range.
 Wireless Wide Area Networks (WAN): A wide-area network, or WAN, is a telecommunications network that connects
various local area networks to each other and to headquarters, cloud servers, and elsewhere. Enterprise WANs allow
users to share access to applications, services, and other centrally located resources.
 Wireless Metropolitan Area Networks (MAN):WMAN is a wireless metropolitan area network that can cover a whole
city. It is larger than WLAN (wireless local area network) and smaller than WWAN (wireless wide area network). WMAN
is managed by any private organization or government agencies. Wireless MAN is accessed by only authorized users. It
can cover a distance of 30 miles. WMAN can establish a network between different buildings or university campuses
within the city.
Types of wireless networks

WLAN WPAN
WWAN WMAN

wireless networks, along with their ranges and typical use:

Sensor

 A wireless sensor is a device that can gather sensory information and detect changes
in local environments.
 Wireless sensors are designed to measure specific parameters about their physical
surroundings and produce outputs, often electrical signals, for further processing.
 A wireless sensor network is made up of sensor nodes. Sensor nodes comprise four basic components
which are the power unit, the sensing unit, the processing unit, and the transceiver unit.
 The sensing unit is made up of data converters and sensors, once an analogue variable; like sound, is
sensed, analogue to digital converters (aka ADCs) convert the signal to digital format before it is passed
into the processing unit. The processing unit is usually a microcontroller which computes the data fed
into it and passes the processed data to a transceiver.
 The processing unit also manages the radio network protocols of the system. As for the power unit, it is
made up of batteries that delivers power for the sensor node to operate. Additional components of a
sensor node include USB connectors, embedded antennas, and oscillators.
What Is A Wireless Sensor?

 Frequency refers to the rate of oscillation (of the radio waves.) RF propagation occurs at the speed of light
and does not need a medium like air in order to travel. RF waves occur naturally from sun flares, lightning,
and from stars in space that radiate RF waves as they age.
 RF communication is used in many industries including television broadcasting, radar systems, computer
and mobile platform networks, remote control, remote metering/monitoring, and many more. While
individual radio components such as mixers, filters, and power amplifiers can be classified according to
operating frequency range, they cannot be strictly categorized by wireless standard (e.g. Wi-Fi, Bluetooth,
etc.) because these devices only provide physical layer (PHY) support.
 In contrast, RF modules, transceivers, and SoCs often include data link layer support for one or more
wireless communication protocols.
RF Wireless Sensors..
 RF wireless sensors are devices that use radio frequency (RF) signals
refer to a wireless electromagnetic signal to communicate wirelessly
with a central hub or controller. Radio waves are a form of
electromagnetic radiation with identified radio frequencies that range
from 3 kHz to 300 GHz.

 Flexibility: RF wireless sensors are easy to install and can be placed in difficult to reach or hazardous
locations without the need for cables or wiring. This flexibility allows for easy reconfiguration and
scalability of the system.
 Reduced installation costs: Without the need for wiring and cabling, the installation costs of RF wireless
sensors are significantly reduced, making them a more cost-effective option.
 Increased reliability: With fewer cables and wires to maintain, RF wireless sensors can provide a more
reliable solution for monitoring and control systems.
 Improved accessibility: RF wireless sensors can be placed in locations that are difficult to access, such as
underground or in hard-to-reach areas.
 Lower maintenance costs: RF wireless sensors require less maintenance than wired sensors, reducing
ongoing maintenance costs.
 Real-time monitoring: RF wireless sensors can provide real-time data, allowing for immediate
identification and response to changes in the monitored environment.
 Reduced power consumption: With the use of energy harvesting or low-power consumption
technologies, RF wireless sensors can operate for extended periods on battery power, reducing the need
for frequent battery replacement or recharging
Advantages

 Limited range: RF wireless sensors have a limited range, and obstacles like walls or other obstructions
can reduce their effective range even further. This can limit the scope and scale of the sensor network.
 Interference: RF wireless sensors are vulnerable to interference from other wireless devices operating on
the same frequency band. This can cause signal loss or corruption, reducing the accuracy and reliability
of the sensor readings.
 Security concerns: Wireless sensor networks can be vulnerable to security breaches, as the signals can
potentially be intercepted or hacked, allowing unauthorized access to the data.
 Battery life: RF wireless sensors are typically battery-powered, and battery life can be limited, depending
on the frequency of transmission and the power requirements of the sensor. This can result in more
frequent battery replacement or recharging, adding to the maintenance costs.
 Cost: While RF wireless sensors may offer reduced installation costs, the initial cost of the sensors and
associated network infrastructure can be higher than wired solutions.
 Data rate: RF wireless sensors typically have lower data rates compared to wired solutions, which can
limit the amount of data that can be transmitted and processed in real-time.
Disadvantages

 Wireless Sensor Networks (WSNs) can be defined as a self-configured and infrastructure-less wireless
networks to monitor physical or environmental conditions, such as temperature, sound, vibration,
pressure, motion or pollutants and to cooperatively pass their data through the network to a main
location.
 A typical sensor network consists of sensors, controller and a communication system. If the
communication system in a Sensor Network is implemented using a Wireless protocol, then the networks
are known as Wireless Sensor Networks or simply WSNs.
WSN
 A Wireless Sensor Network consists of Sensor Nodes (we will see
about this later) that are deployed in high density and often in large
quantities and support sensing, data processing, embedded
computing and connectivity.

 A typical wireless sensor network can be divided into two elements. They are:
 Sensor Node
 Network Architecture
 A Sensor Node in a WSN consists of four basic components. They are:
 Power Supply
 Sensor
 Processing Unit
 Communication System
Elements of WSN

 The sensor collects the analog data from the physical world and an ADC converts this data to digital data.
The main processing unit, which is usually a microprocessor or a microcontroller, performs an intelligent
data processing and manipulation.
 Communication system consists of radio system, usually a short-range radio, for data transmission and
reception. As all the components are low-power devices, a small battery like CR-2032, is used to power
the entire system.
 Despite the name, a Sensor Node consists of not only the sensing component but also other important
features like processing, communication and storage units.
 With all these features, components and enhancements, a Sensor Node is responsible for physical world
data collection, network analysis, data correlation and fusion of data from other sensor with its own data.
Cont..

 Network Architecture: When a large number of sensor nodes are deployed in a large area to co-operatively monitor a
physical environment, the networking of these sensor node is equally important. A sensor node in a WSN not only
communicates with other sensor nodes but also with a Base Station (BS) using wireless communication.
Cont....
 The base station sends commands to the sensor nodes and the sensor node perform the task by collaborating
with each other. After collecting the necessary data, the sensor nodes send the data back to the base station.
 A base station also acts as a gateway to other networks through the internet. After receiving the data from the
sensor nodes, a base station performs simple data processing and sends the updated information to the user
using internet.
 If each sensor node is connected to the base station, it is known as Single-hop network architecture. Although
long distance transmission is possible, the energy consumption for communication will be significantly
higher than data collection and computation.

 Hence, Multi-hop network architecture is usually used. Instead of one single link between the sensor
node and the base station, the data is transmitted through one or more intermediate node.
cont..
•This can be implemented in two ways.
• Flat network architecture and Hierarchical network architecture.
•In flat architecture, the base station sends commands to all the sensor
nodes but the sensor node with matching query will respond using its
peer nodes via a multi-hop path.
•In hierarchical architecture, a group of sensor nodes are formed as a cluster and the sensor nodes
transmit data to corresponding cluster heads. The cluster heads can then relay the data to the base
station.

 OSI stands for Open System Interconnection is a reference
model that describes how information from
a software application in one computer moves through a
physical medium to the software application in another
computer.
 OSI consists of seven layers, and each layer performs a particular
network function.
 OSI model was developed by the International Organization for
Standardization (ISO) in 1984, and it is now considered as an
architectural model for the inter-computer communications.
 OSI model divides the whole task into seven smaller and
manageable tasks. Each layer is assigned a particular task.
 Each layer is self-contained, so that task assigned to each layer
can be performed independently.
OSI Model Visualization

 There are the seven OSI layers. Each layer has different functions. A list of seven layers are given below:
Cont..

 w
Cont..

 w
Layer and Protocols

 M2M stands for machine-to-machine, mobile-to-machine, and machine-to-mobile Communications.
 The automatic communications between devices without any or with very little human intervention. It
often refers to a system of remote sensors that is continuously transmitting data to a central system.
 To simplify, M2M is where two or more machines directly communicate and exchange information to each
other through either a wired or a wireless connection.
 Machine to Machine (M2M) can be defined as a “direct, point-to-point” communication standard between
devices usually of the same type. It’s also meant for a specific on-premise application, which can be
through wired or “non-Internet”-based wireless methods, such as Zigbee, RFID, Bluetooth, Wi-Fi, BLE,
LoRaWAN, Sigfox, 6LoWPAN, and more.
Piller 1: M2M: Machine to Machine

 M2M stands for machine-to-machine, mobile-to-machine, and machine-to-mobile Communications.
Piller 1: M2M: Machine to Machine
 The three main domains of M2M architecture are:
1. M2M application: As the name suggests, the M2M application
domain offers applications to use M2M technology conveniently.
Examples include server and end-user applications.
2. M2M network domain: M2M network domain acts as a bridge
between the M2M application domain and the M2M device domain.
It is made of two parts called the M2M core and M2M service
capabilities.
3. M2M device domain: M2M device domain contains all the
devices that can connect to the M2M network easily. The device
domain can also be called the M2M area network. The M2M device
domain includes devices that can connect directly over a network,
devices that cannot directly connect to a network and may perhaps
require an M2M gateway and proprietary devices.

 M2M devices send data across a network by sensing information.
 M2M stands for "machine-to-machine" communication. It refers to the automated exchange of
data and information between two or more machines or devices, without requiring human
intervention.
 M2M communication is often used in the context of the Internet of Things (IoT), where sensors
and other devices are connected to a network and exchange information with each other in real-
time. For example, a smart thermostat may communicate with a smart meter to adjust the
temperature in a building based on the energy usage and weather conditions.
 M2M communication can be achieved using various technologies and protocols, including cellular
networks, Wi-Fi, Bluetooth, Zigbee, and MQTT. The data exchanged between machines can be in
various formats, such as text, numbers, images, or video.
 M2M communication enables automation and remote monitoring of various processes and
systems, leading to increased efficiency, productivity, and cost savings. It has applications in
various industries, including manufacturing, transportation, healthcare, and agriculture.
Working of M2M

Difference between M2M and IoT

Application.. Smart Water

 A smart water system is an integrated set of sensors and ICT systems that enable utilities to remotely and
continuously monitor and diagnose problems, prioritize and manage maintenance issues and use data to
optimize all aspects of the water distribution network helping to better manage their water assets. It
includes two-way real time communications with field sensors, measurement and control devices; along
with software and services
 Data collection is obtained in part from integrated wireless sensing multi-probes which are deployed
within the water distribution network, enabling sampling and transmittance of relevant data such as
hydraulics (pressure, flow), acoustics (hydrophone) and water quality (pH, ORP and conductivity) in real-
time. However pipes are buried under streets and sidewalks and are difficult and expensive to access.
Further there is no inherent power supply in pipes as there is with electric utilities.
 In the case of agriculture, with sensors and smart controllers, it allows to automatically conserve water
by watering only when it’s needed - take in many different weather variables (temperature, humidity,
wind, and rainfall) and the type of plants, sprinkler heads, and soil to calculate and adjust to the
appropriate run time for that day
Application.. Smart Water

 Smart water metering technology will enable to track usage more accurately at the consumer end and
implement intelligent water pricing plans which would encourage water conservation. Different types of
sensors that are used in Smart water controllers include:
 1. Flow sensors 2. Pressure sensors 3. Sensors for potable water monitoring,
 4. Sensors for chemical leakage detection in rivers 5. Sensors for pollution. 6. Rain sensors
 7. Moisture sensors
 Sensors placed throughout the water distribution network and smart meters at consumer place will help
manage end-to-end distribution, from reservoirs to pumping stations to smart pipes to intelligent
metering at the user site. The sensors could be remotely monitored to provide information about the
state of the pipe and allow taking proactive action on problems detected on the distribution network and
better control over assets. Actions can be taken remotely (e.g. Pressure regulation within a system,
bypassing a section of pipe until maintenance carried out), or even self-healing triggered within a ‘smart
pipeline system’ by the sensors themselves.
Introduction..

 When there are a large number of devices in a network, too many data packets get transmitted over the
same network path. This can lead to congestion and degradation in performance.
 The purpose of networking devices is to enable smooth communication between different hardware
connected to a network. Addition of a network device helps in hassle free sharing of network resources
between different systems.
 While computer network devices like hubs send network data to all connected devices, intelligent
network devices like routers not only have a fixed source and destination system but they also choose the
most efficient route to transmit data.
 Network management is a system that manages and operates multiple networks within a system. A
combination of software and hardware is used in network management systems to gather and analyze
data and push out configuration changes to improve performance, reliability, and security.
Purpose of Networking Devices

 Network devices, or networking hardware, are physical devices that are required for communication and
interaction between hardware on a computer network.
 Types of network devices Here is the common network device list:
 NIC Card and Wi-Fi Card
 Hub
 Switch
 Router
 Bridge
 Gateway
 Modem
 Repeater
 Access Point
What are network devices?
 Link to See working

 The key parts that are required to install a network are included in the components of the Computer
network. From simple to complex there are numerous types of networks in Computer networks.
 The components that we need to install for a network mainly depend upon the type of Network.
 Node
 Media or Link
 Service
 Communication protocols
 Link
 To connect to the Internet and other computers on a network, a computer must have a NIC (network
interface card) installed. A network cable plugged into the NIC on one end and plugged into a cable
modem, DSL modem, router, or switch can allow a computer to access the Internet and connect to other
computers.
Component of computer network..

 Cable. Since they're already in the business of providing data to millions of homes over existing physical
connections, cable TV providers can easily transmit internet over the same wires.
 Digital subscriber line (DSL). A family of technologies that permit digital data across copper telephone
lines, DSL can provide a roughly similar level of service as cable, but without the need for an underlying
cable subscription. In fact, using a "dry copper" connection, you don't even need a telephone landline
account.
 Fiber optics. Due to some arcane technical details (including the laws of physics), transmitting digital
signals as infrared light can happen faster and require fewer repeaters than comparable electrical cables.
A fiber optics internet connection could typically deliver transfer speeds of 10-40Gbit/s – a thousand
times faster than currently standard rates using cable or DSL.
 Satellite. Running new cable through densely populated cities is expensive, but companies can quickly
make their money back through the many access contracts they'll sign. But sparsely populated rural
regions are much more difficult to service. Partly to fill a rural connectivity gap, a number of companies
ambitiously working to launch constellations of thousands of orbiting satellites to provide universal
internet coverage. As of this writing, SpaceX is furthest along with its project, having already successfully
launched more than 500 satellites as part of the Starlink system. Link
Computer Connect to Network..

How to Connect my device to the Internet
This all depends on the role of the device and we have
the following options:
Option 1) We access this device only on the home /
business network
Option 2) The device only connects to a local / remote
server
Option 3) We access this device from the Internet using
a Static Public IP Address
Option 4) We access this device from the Internet using
a Dynamic Public IP Address
Fig: OPTION1

OPTION 2
•For this scenario the IoT device initiates a
connection to a local or remote server.
•This could be using a http REST POST or
configured as MQTT client.
•It could also be a custom connection method
as long as it initiates the connection to the
remote service.
Because the device is creating the connection it
allows us to use DHCP and a dynamically
assigned IP address.

OPTION3
This means ISP's are pretty strict on giving out static IP addresses.
It's much easier for them to use a dynamic pool of IP addresses to
assign to their clients.
Generally home internet services are not available with a static IP
address. However you might be able to pay extra for this
functionality. Some business accounts are available with a static IP
address. The most common reason for wanting a static ip is for
hosting a email server.
To connect from the home / office router to your IoT device we need
to perform Network Address Translation or Port Forwarding on this
router. Through the router administration console we need to tell the
router to forward any data packets it receives on it's WAN interface
(Internet) using a specific port number is forwarded onto the internal
IP address we have assigned to the IoT device.
So when a browser sends a request using the public IP address
1.127.48.156 it hits the router. The router will check its NAT / Port
forwarding table and find a match for port 80 or alternatively port
49155. It will then forward the data packet to the internal IP address
192.168.1.45 that was setup in the routers configuration.

OPTION 4
One of the most common ways of dealing with a dynamic public
(WAN) IP addresses is to use a Dynamic DNS Service provider.
Some of these services are free but most require a monthly
payment.
Most routers these days support third party Dynamic DNS service
providers. You configure the router with the provider, username
and password. WHen the router detects a WAN interface IP
address change it updates the DDNS service provider with the
new IP details.
When you signup with one of these providers you provide a
domain name you would like to use. In the example below the
name we used is cactusio. This is a subdomain for dydns.com.
When we enter http://cactusio.dydns.com into the browser it will
do a dnslookup on cactusio.dydns.com. If its a valid domain it will
respond with the IP address which just happens to be the public
(WAN) IP address of the home / office router.
The office router will detect the data packet matches a record in
the port forwarding table and pass the data onto the IoT device
using the static ip of 192.168.1.45. The IoT device will respond
with the appropriate html to view in the internet client browser.

 Internet of Things (IOT) is the technology that allows us to
transmit data from and commands to smart devices in real-
time.
 IoT is a network of devices connected via the Internet, with
a hub that can analyze the aggregated data. The IoT
endpoints can be a person, an animal, a home, a farm, a
building, or a whole city.
 But in all cases these things “talk” to each other without any
human intervention via an IoT protocol.
IOT Protocols..

 CoAP is a simple protocol with low overhead specifically
designed for constrained devices (such as microcontrollers)
and constrained networks. This protocol is used in M2M data
exchange
 MQTT (Message Queuing Telemetry Transport ) is a machine
to machine internet of things connectivity protocol. MQTT is
based on subscriber, publisher and broker model. Within the
model, the publisher’s task is to collect the data and send
information to subscribers via the mediation layer which is
the broker.
 HTTP stands for Hypertext Transfer Protocol, an application
protocol for distributed, collaborative, hypermedia
information systems that allows users to communicate data
on the World Wide Web
 Example: http://www………: URL beginning with HTTP
scheme
Introduction..

 HTTP stands for Hypertext Transfer Protocol, an application protocol for distributed, collaborative,
hypermedia information systems that allows users to communicate data on the World Wide Web
 Example: http://www………: URL beginning with HTTP scheme
 To be more specific, HTTP is a stateless request/response protocol where clients request information
from a server and the server responds to these requests accordingly (each request is independent of the
other). It allows the fetching of resources, such as HTML document
 HTTP was invented alongside HTML to create the first interactive, text-based web browser: the original
World Wide Web. Today, the protocol remains one of the primary means of using the Internet.
HTTP..

 HTTP data rides above the TCP protocol, which guarantees reliability of delivery, and breaks down large
data requests and responses into network-manageable chunks.
 This is how it works: at first, clients send a SYN packet to the server and then the web server will respond
with SYN-ACK packet to confirm success of receiving.
 After which, the client again sends a ACK packet, concluding a connection establishment – this is also
commonly referred to as a 3-way handshake.
 In addition, the client sends a HTTP request to the server for a resource and waits for it to respond to a
request.
 Then the web server will process the request, find the resource and send the response to the client. If no
more resources are required by the client, it sends a FIN packet to close the TCP connection.
Working..

 HTTP protocol is used for bootstrap the World Wide Web to transmit data in the form of text, audio,
images, and video from the Web Server to the user’s web browser and vice versa.
 HTTP is currently the data transmission platform of today’s web browsing application and is widely used
in Internet of Things systems. Even though Http protocol has many disadvantages in transmitting data
and is not as suitable as those proficient protocols such as MQTT, CoAP, AMQP using for IoT, this protocol
is still popular in smart-home industry as well as many advanced microcontrollers and microprocessor.
HTTP Applications
Advantages of applying HTTP:
1. Search capabilities: Although HTTP is a simple messaging protocol, it includes the ability to search a
database with a single request. This allows the protocol to be used to carry out SQL searches and return
results conveniently formatted in an HTML document.
2. Ease of programming: HTTP is coded in plain text and therefore is easier to follow and implement than
protocols that make use of codes that require lookups. Data is formatted in lines of text and not as strings
of variables or fields.
3. Security: HTTP 1.0 downloads each file over an independent connection and then closes the connection.
So this reduces the risk of interception during transmission significantly

Disadvantages of applying HTTP protocol:
1. Not suitable for small devices: As small devices, such as wireless sensor, do not require much interaction
and they consume very little power, HTTP is too heavy to be a good fit for these devices. An HTTP
request requires a minimum of nine TCP packets, even more when you consider packet loss from poor
connectivity, and plain text headers can get very verbose.
2. Not designed for event-based communication: Most of the IOT applications are event based. The sensor
devices measure for some variable like temperature, air quality and might need to take event driven
decisions like turning off a switch HTTP was designed for a request-response based communication rather
than an event-driven communication. Also, programming this event based systems using HTTP protocol
becomes a big challenge especially because of the limited computing resources on the sensor devices.
3. Real-time problem: After requesting a resource to the server, the client has to wait for the server to
respond, leading to slow transfer of data. IOT sensors are small devices with very limited computing
resources and hence cannot work efficiently in a synchronous manner. All the widely used IOT protocols are
based on asynchronous models.
Introduction..

 CoAP is a simple protocol with low overhead specifically designed for constrained devices (such as
microcontrollers) and constrained networks. This protocol is used in M2M data exchange and is very
similar to HTTP, even if there are important differences that we will discuss later.
 CoAP has the following main features:
 Constrained web protocol fulfilling M2M requirements.
 Security binding to Datagram Transport Layer Security (DTLS).
 Asynchronous message exchanges.
 Low header overhead and parsing complexity.
 URI and Content-type support.
 Simple proxy and caching capabilities.
 Optional resource discovery.
 UDP (User Datagram Protocol) binding with optional reliability supporting unicast and multicast
requests.
Constrained Application Protocol (CoAP)..

 CoAP interactive model is similar to HTTP’s client/server model. CoAP employs a two layers structure.
The bottom layer is a message layer that has been designed to deal with UDP and asynchronous
switching. The request/response layer concerns communication methods and deals with
request/response messages.
CoAP Structure Model

 Message Layer supports 4 types of messages: CON (Confirmable), NON (Non-confirmable), ACK
(Acknowledgement), RST (Reset).
 Reliable message transport: A CON message is retransmitted until the recipient sends an ACK message
with the same message ID. Using default timeout and decreasing counting time exponentially when
transmitting a CON message. If a recipient is not able to process a message, it responses by replacing ACK
message with RST message.
 Unreliable message transport: A message that does not require reliable delivery, can be sent as a NON
message. These are not acknowledged, but still have a message ID for duplicate detection. Figure 3 shows
unreliable message transport
CoAP Messages Model
Unreliable
message delivery
Reliable message
delivery

 It is a simple protocol and uses less overhead due to operation over UDP. It allows short wake up times and long sleepy states. This
helps in achieving long battery life for use in
 It uses IPSEC (IP Security) or DTLS (Datagram Transport Layer Security) to provide secure communication.
 Synchronous communication is not necessary in CoAP protocol.
 It has lower latency compared to HTTP.
 It avoids unnecessary retransmissions so that it consumes less power than HTTP.
 CoAP protocol is used as the best protocol choice for home communication networks. It is used in information appliances,
communication equipment and control equipment in smart home networks.
 Disadvantages of CoAP protocol
 CoAP is an unreliable protocol due to the use of UDP. Hence CoAP messages reach unordered or will get lost when they arrive at
destination
 It acknowledges each receipt of the message and hence increases processing time. Moreover, it does not verify whether the received
message has been decoded properly or not.
 It is an unencrypted protocol like MQTT and uses DTLS to provide security at the cost of implementation overhead.
 CoAP has communication issues for devices behind NAT (Network Address Translation).
Advantages and Disadvantages of CoAP..

 It is a publish and subscribe system where we can publish and receive the messages as a client. It makes it easy for
communication between multiple devices.
 It is a simple messaging protocol designed for the constrained devices and with low bandwidth, so it’s a perfect
solution for the internet of things applications.
 Developed as an open OASIS standard and an ISO recommended protocol, the MQTT was aimed to operate on data
transmissions with a small bandwidth and minimum resources (e.g. on microcontrollers).
 It usually uses the TCP/IP protocol suite, which runs by first establishing connections, then allows multiple
exchanges of data until one party finally disconnects itself.
 The MQTT technology runs using the MQTT Publish/Subscribe architecture and establishes the network from 2
different component categories: Clients (Publisher and Subscriber) and Brokers.
MQTT..

MQTT Publisher, Broker and Subscriber
 MQTT Publisher MQTT Broker
 MQTT Subscriber

 The MQTT has some unique features which are hardly found in other protocols. Some of the features of
an MQTT are given below:
 It does not require that both the client and the server establish a connection at the same time.
 It allows the clients to subscribe to the narrow selection of topics so that they can receive the information
they are looking for.
 It provides faster data transmission, like how WhatsApp/messenger provides a faster delivery. It’s a real-
time messaging protocol.
 It is designed as a simple and lightweight messaging protocol that uses a publish/subscribe system to
exchange the information between the client and the server.
 It is a machine to machine protocol, it provides communication between the devices.
Characteristics of MQTT..

 To understand the MQTT architecture, we first look at the components of the MQTT: message, client,
server and topic.
 Message: The message is the data that is carried out by the protocol across the network for the
application. When the message is transmitted over the network, then the message contains the following
parameters: Payload data, Quality of Service (QoS), Collection of Properties and Topic Name
 Client: In MQTT, the subscriber and publisher are the two roles of a client. The clients subscribe to the
topics to publish and receive messages. In simple words, we can say that if any program or device uses an
MQTT, then that device is referred to as a client. A device is a client if it opens the network connection to
the server, publishes messages that other clients want to see, subscribes to the messages that it is
interested in receiving, unsubscribes to the messages that it is not interested in receiving, and closes the
network connection to the server.
 In MQTT, the client performs two operations:
 Publish: When the client sends the data to the server, then we call this operation as a publish.
 Subscribe: When the client receives the data from the server, then we call this operation a
subscription.
MQTT Architecture..

 Server: The device or a program that allows the client to publish the messages and subscribe to the
messages. A server accepts the network connection from the client, accepts the messages from the client,
processes the subscribe and unsubscribe requests, forwards the application messages to the client, and
closes the network connection from the client.
 Topic: The label provided to the message is checked against the subscription known by the server is
known as TOPIC.
Cont..

Example..

 Advantages of MQTT protocol:
 Efficient data transmission and quick to implement due to its being a lightweight protocol;
 Low network usage, due to minimize data packets;
 Efficient distribution of data;
 Successful implementation of remote sensing and control;
 Fast and efficient message delivery;
 Usage of small amounts of power, which is good for the connected devices;
 Reduction of network bandwidth
 Disadvantages of MQTT protocol:
 MQTT has slower transmit cycles compared to CoAP.
 MQTT’s resource discovery works on flexible topic subscription, whereas CoAP uses a stable resource discovery system.
 MQTT is unencrypted. Instead, it uses TLS (Transport Layer Security)/SSL (Secure Sockets Layer) for security encryption.
 It is difficult to create a globally scalable MQTT network.
Advantages and Disadvantages ..

 w
Criteria MQTT HTTP CoAP
Year 1999 1997 2010
Form Message Queue Telemetry Transport Hypertext Transfer Protocol Constrained Application Protocol
Architecture Client/Broker Client/Server Client/Server
Pattern Publish/Subscribe Request/Response Request/Response
Header Size 2 Byte Undefined 4 Byte
Message Size
Small and Undefined (up to 256 MB
maximum size)
Large and Undefined
(depends on the web server)
Small and Undefined (normally
small to fit in single IP datagram)
Semantics/Methods
Connect, Disconnect, Publish,
Subscribe, Unsubscribe, Close
Get, Post, Head, Put, Patch,
Options, Connect, Delete
Get, Post, Put, Delete
Cache & Proxy Support Partial Yes Yes
Quality of Services
(QoS)/Reliability
QoS 0 – At most once
(Fire and Forget)
QoS 1 – At least once
QoS 2 – Exactly once
Limited (via Transport Protocol
– TCP)
Confirmable Message (similar to At
most once) or Non-confirmable
(similar to At least once)
Transport Protocol TCP TCP
UDP, (Stream Control
Transmission Protocol)
Security TLS /SSL TLS/SSL DTLS , IPsec
Default Port 1883/8883 (TLS/SSL) 80/443 (TLS/SSL) 5683 (UDP Port)
Encoding Format Binary Text Binary
Licensing Model Open Source Free Open Source
Organizational Support
IBM, Facebook, Eurotech, Cisco, Red
Hat, Software AG, Tibco, ITSO, M2Mi,
Global Web Protocol Standard
Large Web Community Support,

 AMQP, like MQPP, is a message queuing protocol. This means that the subscriber and publisher of the
system communicate by sending and requesting messages from a ‘message queue’. This standard satisfies
the need for IoT applications on asynchronous communication, ensuring that the system is flexible
enough to enable communication across numerous ‘things’.
 AMQP deals with publishers and consumers. The publishers produce the messages, the consumers pick
them up and process them. It’s the job of the message broker (such as RabbitMQ) to ensure that the
messages from a publisher go to the right consumers.
AMQP (Advanced Message Queueing Protocol)
A publisher sends messages to a named exchange and a
consumer pulls messages from a queue or the queue pushes
them to the consumer depending on the configuration.
It sends transaction message between servers
Broker (or server) plays a crucial role in AMQP protocol
enablement. It is responsible for connection building that
ensure better data routing and queuing at the client-side.

 DDS stands for Data Distribution Service, an open standard for real-time applications. The Object Management Group
Data Distribution Service, is a middleware protocol and API standard that aims to enable high-performance,
interoperable, scalable data exchanges using a publish-subscribe pattern.
 Its operation claims to provide a secure and real-time data distribution. Like MQTT, DDS works in a
Publisher/Subscriber architecture.
 DDS is a machine-to-machine technology used for publish-subscribe middleware applications in real-time and
embedded systems
 DDS protocol for real-time M2M communication enables scalable, reliable, high-performance, and interoperable data
exchange between connected devices independent of the hardware and the software platform. DDS supports broker-
less architecture and multicasting to provide high-quality QoS and ensure interoperability.
DDS

 For example, when the artificial intelligence (AI) of an autonomous car needs to issue a “turn left”
command, DDS is used to transport that command from the electronic control unit (ECU) (the car’s
“brain”) down to the steering servomotors. The same instance also happens when speed sensors send
information from the motor up to the ECU. We verified that the DDS runs successfully on starter kit ECUs,
making any autonomous vehicle based on this hardware and software stack susceptible to our findings.
 Another example is when an airport operator inside the air traffic control tower needs to illuminate the
runway of an airport. In modern airports, these specific signals are transmitted via software, and DDS is
used to ensure timely delivery of those commands. The average airport runway has thousands of control
points: considering there are more than 10,000 (expected to become 44,000) airports in the world, each
with an average of 2.5 runways (up to 36), even if only 1% of them would be using DDS (conservatively),
this would make roughly 250,000 DDS nodes (up to 1.1M) in airports alone.
DDS Examples

IoT device management
• Range
• Communication range is a function of the device’s built-in power management and the antennas integrated into the device or attached
externally. Communication range is therefore in the control of the organization, without any advanced IoT device management tools, but
testing and reporting on range are much easier with an IoT device management platform.
Bandwidth
• Bandwidth in a deployed IoT application is a function of the device’s built-in capabilities such as the type of modem (e.g. 3G, 4G LTE or 5G),
and the available network. Advanced (contextual) IoT device management tools are not required to manage this functionality, but they
provide the ability to test bandwidth and gain visibility across the network.
Battery Life
• Battery life is a function of the device design and its application. A deployed device in a remote oil well, for example, will use battery power
each time it sends data. Edge computing techniques can help to optimize these processes, and are most easily managed with advanced IoT
device management solutions like Digi Remote Manager.
• Remote management: Each device on a network plays an important role, even when the network devices number in the thousands or
millions. Contextual IoT device management provides the ability to manage and update any of those devices anytime to troubleshoot issues
or enhance functionality.
• Security: Integrated security tools can detect and remediate security breaches, while also providing 24/7 visibility and reporting on these
incidents from a management interface.
• Scalability: The ability to grow the size of a deployment is dependent on the organization’s ability to remotely monitor and manage devices
from a central management interface, or from a mobile device in the field.
• Network optimization: To optimize data usage, battery life and functionality of devices at the network edge, organizations need tools to
deploy software changes.

Interacting without human intervention - the Internet of Things (IoT)(M2M)
• Any imaginable thing can be connected to the internet and interact without the need for human intervention; the goal is machine-to-
machine (M2M) interaction. The Internet of Things is making the world around us smarter and more responsive, merging the digital and
physical universes. According to McKinsey Digital magazine, 127 devices connect to the internet for the first time every second.

IOT PROTOCOLS
IoT Network Protocols
• Wi-Fi
• LTE CAT 1
• LTE CAT M1
• NB-IoT
• Bluetooth
• ZigBee
• LoRaWAN
IoT Data Protocols
• AMQP
• MQTT
• HTTP
• CoAP
• DDS
• LwM2M
Wi-Fi
• Wi-Fi is a ubiquitous protocol that can be found almost anywhere—industrial plants, homes, commercial buildings, and even your neighborhood restaurants. This widely favored
technology is able to transmit large volumes of data over reasonable distances. However, many low-power or battery-powered IoT devices are unlikely to use Wi-Fi due to its high power
consumption rate.
LTE CAT 1
• LTE CAT 1 is a communication standard specifically designed for servicing IoT applications. Compared with other standards, it scales down bandwidth and communication demand to save
power and cost for large-scale and long-range IoT systems.
LTE CAT M1
• LTE CAT M1—which can also be referred to as Cat-M—is a low-cost, low-power, wide-area network that specializes in transferring low to medium amounts of data.
NB-IoT
NB-IoT's advantages include improvements in power consumption, system capacity, and spectrum efficiency. For example, NB-IoT can connect huge fleets with up to 50,000 devices per
network cell.
Bluetooth
• Bluetooth focuses on point-to-point, short-range communication of a relatively small amount of data.

ZigBee
• Ratified in the early 2000s, ZigBee stands out as a low-cost, low-power, and reliable wireless network technology. The standard is adaptable and supports multiple
network topologies, including mesh networks, point-to-multipoint, and point-to-point.
LoRaWAN
• Long-range wide area network—also referred to as LoRa—is a long-range, radio-wide networking protocol with low power consumption. Normally, LoRaWAN
wirelessly connects multiple battery-operated devices to the Internet within regional, national, or global networks.
AMQP
• Known for its reliability and interoperability, Advanced Message Queuing Protocol is an open messaging standard. This protocol utilizes queues of data, enabling
connected systems to communicate asynchronously and better handle issues like traffic spikes and poor network conditions.
MQTT
• Message Queue Telemetry Transport is a lightweight pub/sub messaging protocol suitable for connecting small, low-power devices.
HTTP
• You might recognize this acronym as appearing at the beginning of every website address you type, as Hypertext Transfer Protocol is the foundation of data
communication for the World Wide Web.
CoAP
• Constrained Application Protocol is used with constrained nodes and networks. This protocol is suited for IoT applications as it reduces the size of network
packages, thereby decreasing network bandwidth overload.
DDS
• Released in 2004, Data Distribution Service is a middleware architecture for real-time systems that focus on data communication between the nodes of a
publication- or subscription-based messaging architecture.
• DDS is mainly used under circumstances that require real-time data exchange—for example, autonomous vehicles, power generation, and robotics.
LwM2M
• Lightweight Machine-to-Machine protocol is designed for remote management of M2M devices and related services. LwM2M reduces costs associated with low-
power module deployment and equipping devices with faster IoT solutions

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