INTERNET OF THINGS MODULE -1

MODULE-1 INTRODUCTION TO INTERNET OF THINGS

Introduction - Definition and Characteristics of IoT - Physical design

,Logical design ,IOT Enabling technologies , IoT Levels And Deployment
templates.

1.1 Introduction

The Internet of Things represents the whole way from collecting data, processing it, taking
an action corresponding to the signification of this data to storing everything in the cloud. All
this is made possible by the internet.

The Internet of things has become a very widely spread concept in the last few years. The
reason for this is mainly the need to computerize and control most of the surrounding objects
and have access to data in real time.

Example: Parking sensors, about phones which can check the weather and so on.

1.1.1 Definition & Characteristics of IoT Definition:

A dynamic global n/w infrastructure with self configuring capabilities based on standard and
interoperable communication protocols where physical and virtual ―things‖ have identities,
physical attributes and virtual personalities and use intelligent interfaces, and are seamlessly
integrated into information n/w, often communicate data associated with users and their
environments.
Characteristics of IoT

i)Dynamic & Self Adapting:

IoT devices and systems may have the capability to dynamically adapt with the changing

contexts and take actions based on their operating conditions, user‘s context or sensed
environment.

Eg: The surveillance system comprising of a number of surveillance cameras. The

surveillance camera can adapt modes based on whether it is day or night. The surveillance
system is adapting itself based on context and changing conditions.
ii)Self Configuring:

IOT devices have self configuring capability,allowing a large number of devices to work
together to provide certain functionality. These devices have the ability configure themselves
setup networking, and fetch latest software upgrades with minimal manual or user interaction.

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iii) Inter Operable Communication Protocols: support a number of interoperable

communication protocols and can communicate with other devices and also with
infrastructure.

iv) Unique Identity: Each IoT device has a unique identity and a unique identifier(IP address).

v) Integrated into Information Network: that allow them to communicate and exchange data
with other devices and systems.

Applications of IoT:

1) Home

2) Cities

3) Environment

4) Energy

5) Retail

6) Logistics
7) Agriculture

8) Industry

9) Health &LifeStyle

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1.2 Physical Design of IoT :

1.2.1 Things in IOT

The "Things" in IoT usually refers to IoT devices which have unique identities and can
perform remote sensing, actuating and monitoring capabilities.

IoT devices can:

Exchange data with other connected devices and applications (directly or indirectly), or

Collect data from other devices and process the data locally or
Send the data to centralized servers or cloud-based application back-ends for processing
the data,
Perform some tasks locally and other tasks within the IoT infrastructure, based on temporal
and space constraints

Generic block diagram of an IoT Device

• An IoT device may consist of several interfaces for connections to other devices, both wired
and wireless.
• I/O interfaces for sensors
• Interfaces for Internet connectivity

• Memory and storage interfaces

• Audio/video interfaces.

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• HDMI: High definition multimedia Interface.

• 3.5mm: Audio Jack which headphone adapter.

• RCA: Radio corporation of America.

• UART: Universal Asynchronous Receiver Transmitter.

• SPI: Serial Peripheral Interface.

• I2C: Inter integrated circuit

• CAN: Controller Area Network used for Micro-controllers and devices to communicate.

• SD: Secure digital (memory card)

• MMC: multimedia card

• SDIO: Secure digital Input Output

• GPU: Graphics processing unit.

• DDR: Double data rate

1.2.2 IoT Protocols:

a) Link Layer :

Protocols determine how data is physically sent over the network‘s physical layer or medium.
Local network connect to which host is attached. Hosts on the same link exchange data
packets over the link layer using link layer protocols. Link layer determines how packets are
coded and signalled by the h/w device over the medium to which the host is attached.

Protocols OF Link layer:

802.3-Ethernet: IEEE802.3 is collection of wired Ethernet standards for the link layer. Eg:
802.3 uses co-axial cable; 802.3i uses copper twisted pair connection; 802.3j uses fiber optic
connection; 802.3ae uses Ethernet overfiber.

802.11-WiFi: IEEE802.11 is a collection of wireless LAN(WLAN) communication

standards including extensive description of link layer. Eg: 802.11a operates in 5GHz band,
802.11b and 802.11g operates in 2.4GHz band, 802.11n operates in 2.4/5GHz band, 802.11ac
operates in 5GHz band, 802.11ad operates in60Ghzband.

802.16 - WiMax: IEEE802.16 is a collection of wireless broadband standards including

exclusive description of link layer. WiMax provide data rates from 1.5 Mb/s to 1Gb/s.

802.15.4-LR-WPAN: IEEE802.15.4 is a collection of standards for low rate wireless

personal area network(LR-WPAN). Basis for high level communication protocols such as
ZigBee. Provides data rate from 40kb/s to250kb/s.
2G/3G/4G-Mobile Communication: Data rates from 9.6kb/s(2G) to up to100Mb/s(4G). B)

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b) Network/Internet Layer:

Responsible for sending IP datagrams from source n/w to destination n/w. Performs the host

addressing and packet routing. Datagrams contains source and destination address.
Protocols of network layer:

IPv4: Internet Protocol version4 is used to identify the devices on a n/w using a
hierarchical addressing scheme. 32 bit address. Allows total of 2*32addresses.
IPv6: Internet Protocol version6 uses 128 bit address scheme and allows 2*128 addresses.

6LOWPAN:(IPv6 over Low power Wireless Personal Area Network) operates in 2.4 GHz
frequency range and data transfer 250 kb/s.

c) Transport Layer:

Provides end-to-end message transfer capability independent of the underlying n/w. Set up on

connection with ACK as in TCP and without ACK as in UDP. Provides functions such as
error control, segmentation, flow control and congestion control.

Protocols of transport layer:

TCP: Transmission Control Protocol used by web browsers(along with HTTP and
HTTPS), email(along with SMTP, FTP). Connection oriented and stateless protocol. IP
Protocol deals with sending packets, TCP ensures reliable transmission of protocols in order.
Avoids n/w congestion and congestioncollapse.
UDP: User Datagram Protocol is connectionless protocol. Useful in time sensitive

applications, very small data units to exchange. Transaction oriented and stateless protocol.
Does not provide guaranteed delivery.

d) Application Layer:

Defines how the applications interface with lower layer protocols to send data over the n/w.
Enables process-to-process communication using ports.

Protocols of application layer:

HTTP: Hyper Text Transfer Protocol that forms foundation of WWW. Follow request
response model Stateless protocol.

CoAP: Constrained Application Protocol for machine-to-machine(M2M) applications with

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constrained devices, constrained environment and constrained n/w. Uses client-server

architecture.

WebSocket: allows full duplex communication over a single socket connection.

MQTT: Message Queue Telemetry Transport is light weight messaging protocol based on
publish-subscribe model. Uses client server architecture. Well suited for constrained
environment.

XMPP: Extensible Message and Presence Protocol for real time communication and
streaming XML data between network entities. Support client-server and server-server
communication.
DDS: Data Distribution Service is data centric middleware standards for device-to-device
or machine-to-machine communication. Uses publish-subscribe model.

AMQP: Advanced Message Queuing Protocol is open application layer protocol for
business messaging. Supports both point-to-point and publish-subscribe model.

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1.3 LOGICAL DESIGN of IoT

Logical design of IOT refers to an abstract represent of entities and processes without going
into the low level specifies of implementation.

1) IoT Functional Blocks

2) IoT Communication Models

3) IoT Comm. APIs

1.3.1) IoT Functional Blocks:

Provide the system the capabilities for identification, sensing, actuation, communication and
management.The functional blocks are described as follows:

Device: An IoT system comprises of devices that provide sensing, actuation, monitoring
and control functions.

Communication: handles the communication for IoT system.

Services: for device monitoring, device control services, data publishing services and
services for device discovery.

Management: Provides various functions to govern the IoT system.

Security: Secures IoT system and priority functions such as authentication, authorization,
message and context integrity and data security.

Application: IoT application provide an interface that the users can use to control and
monitor various aspects of IoT system.

1.3.2) IoT Communication Models:

A) Request-Response
B) Publish-Subscribe

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C)Push-Pull

D) Exclusive Pair

A) Request-Response
Request-Response is a communication model in which the client sends requests to the server
and the server responds to the requests. When the server receives a request, it decides how to
respond, fetches the data, retrieves resource representations, prepares the response, and then
sends the response to the client.

B) Publish-Subscribe communication model:

a. Publish-Subscribe is a communication model that involves publishers, brokers and

consumers.

b. Publishers are the source of data. Publishers send the data to the topics which are managed
by the broker. Publishers are not aware of the consumers.

c. Consumers subscribe to the topics which are managed by the broker.

d. When the broker receives data for a topic from the publisher, it sends the data to all the
subscribed consumers

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C) Push-Pull communication model:

a. Push-Pull is a communication model in which the data producers push the data to queues
and the consumers pull the data from the queues. Producers do not need to be aware of the
consumers.

b. Queues help in decoupling the messaging between the producers and consumers.

c. Queues also act as a buffer which helps in situations when there is a mismatch between the
rate at which the producers push data and the rate at which the consumers pull.

D) Exclusive Pair communication model:

a.Exclusive Pair is a bidirectional, fully duplex communication model that uses a persistent

connection between the client and server.

b.Once the connection is setup it remains open until the client sends a request to close the

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connection.

c.Client and server can send messages to each other after connection setup.

1.3.3 IOT COMMUNICATION APIs:

a) REST based communication APIs(Request-Response Based Model)

b) WebSocket based Communication APIs(Exclusive PairBasedModel)

a) Request-Response model used by REST:

RESTful webservice is a collection of resources which are represented by URIs. RESTful

web API has a base URI(e.g: http://example.com/api/tasks/). The clients and requests to these
URIs using the methods defined by the HTTP protocol(e.g: GET, PUT, POST or DELETE).
A RESTful web service can support various internet media types.

b) WebSocket Based Communication APIs:

WebSocket APIs allow bi-directional, full duplex communication between clients and
servers. WebSocket APIs follow the exclusive pair communication.

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1.4 IoT Enabling Technologies

IoT is enabled by several technologies including Wireless Sensor Networks, Cloud

Computing, Big Data Analytics, Embedded Systems, Security Protocols and architectures,
Communication Protocols, Web Services, Mobile internet and semantic search engines.

1.4.1 Wireless Sensor Networks

A wireless sensor network comprises of distributed devices with sensors which are used to
monitor the environmental and physical conditions. A WSN consist of a number of end nodes
and routers and a co- ordinator. The coordinator collects the data from all the nodes.
Coordinator also acts as a gateway that connects the WSN to the internet. WSNs used in IoT
systems are described as follows:

• Weather Monitoring System: in which nodes collect temp, humidity and other data, which is

aggregated and analyzed.

• Indoor air quality monitoring systems: to collect data on the indoor air quality and

concentration of various gases.

• Soil Moisture Monitoring Systems: to monitor soil moisture at various locations.

• Surveillance Systems: use WSNs for collecting surveillance data(motion data detection).
• Smart Grids : use WSNs for monitoring grids at various points.

• Structural Health Monitoring Systems: Use WSNs to monitor the health of

structures(building, bridges) by collecting vibrations from sensor nodes deployed at various

points in the structure.

WSNs are enabled by wireless communication protocols such as IEEE 802.15.4. Zig Bee is
one of the most popular wireless technologies used by WSNs .Zig Bee specifications are
based on IEEE 802.15.4. Zig Bee operates 2.4 GHz frequency and offers data rates upto 250
KB/s and range from 10 to 100meters.

1.4.2 Cloud Computing

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Cloud computing is a transformative computing paradigm that involves delivering

applications and services over the internet. Cloud computing involves provisioning of
computing, networking and storage resources on demand and providing these resources as
metered services to the users, in a “pay as you go”.Cloud computing resources can be
provisioned on-demand by the users, without requiring interactions with the cloud service
provider. The process of provisioning resources is automated. Cloud computing services are
offered to users in different forms.

• Infrastructure-as-a-service(IaaS):Provides users the ability to provision computing and

storage resources. These resources are provided to the users as a virtual machine instances
and virtual storage.

• Platform-as-a-Service(PaaS): Provides users the ability to develop and deploy application in

cloud using the development tools, APIs, software libraries and services provided by the
cloud service provider.

• Software-as-a-Service(SaaS): Provides the user a complete software application or the user

interface to the application itself. The cloud service provider manages the underlying cloud
infrastructure including servers, network, operating systems, storage, and application
software.

1.4.3 Big data Analysis

Big data is defined as collections of data sets whose volume , velocity or variety is so large
that it is difficult to store, manage, process and analyze the data using traditional databases
and data processing tools.

Some examples of big data generated by IoT are Sensor data generated by IoT systems.
• Machine sensor data collected from sensors established in industrial and energy systems.

• Health and fitness data generated IoT devices.

• Data generated by IoT systems for location and tracking vehicles.

• Data generated by retail inventory monitoring systems.

The underlying characteristics of Big Data are:

Volume: There is no fixed threshold for the volume of data for big data. Big data is used for
massive scale data.

Velocity: Velocity is another important characteristics of Big Data and the primary reason for
exponential growth of data.

Variety: Variety refers to the form of data. Big data comes in different forms such as
structured or unstructured data including test data, image , audio, video and sensor data .

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1.4.4 Communication Protocols:

Communication Protocols form the back-bone of IoT systems and enable network
connectivity and coupling to applications.

• Allow devices to exchange data over network.

• Define the exchange formats, data encoding addressing schemes for device and routing of

packets from source to destination.

• It includes sequence control, flow control and retransmission of lost packets.

1.4.5 Embedded Systems:

Embedded Systemsis a computer system that has computer hardware and software embedded
to perform specific tasks. Key components of embedded system include microprocessor or
micro controller, memory (RAM, ROM, Cache), networking units (Ethernet Wi-Fi Adaptor),
input/output units (Display, Keyboard, etc..,) and storage (Flash memory). Embedded System
range from low cost miniaturized devices such as digital watches to devices such as digital
cameras, POS terminals, vending machines, appliances etc.,

1.5 IOT Levels and Deployment Templates.

1.5.1 IoT Level-1
Level-1 IoT systems has a single node that performs sensing and/or actuation, stores data,
performs analysis and host the application. Suitable for modeling low cost and low
complexity solutions where the data involved is not big and analysis requirement are not
computationally intensive. An e.g., of IoT Level1 is Homeautomation.The system consist of a
single node that allows controlling the lights and appliances in a home the device used in this
system interfaces with the lights and appliances using electronic rely switches. The status
information of each light or appliances is maintained in a local database. REST services
deployed locally allow retrieving and updating the state of each lighter appliance in the status
database. The controller service continuously monitors the state of each light or appliance by
retrieving the light from the database.

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1.5.2 IoT Level 2

IoT Level2 has a single node that performs sensing and/or actuating and local analysis as
shown in fig. Data is stored in cloud and application is usually cloud based. Level2 IoT
systems are suitable for solutions where data are involved is big, however, the primary
analysis requirement is not computationally intensive and can be done locally itself. An e,g.,
of Level2 IoT system for Smart Irrigation.The system consists of a single node that monitors
the soil moisture level and controls the irrigation system.The device used system collects soil
moisture data from sensors. The controller service continuously monitors the moisture level.
A cloud based REST web service is used for storing and retrieving moisture data which is
stored in a cloud database. A cloud based application is used for visualizing the moisture level
over a period of time which can help in making decision about irrigation schedule.

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1.5.3 IoT Level 3

This System has a single node. Data is stored and analyzed in the cloud application is cloud
based as shown in fig. Level3 IoT systems are suitable for solutions where the data involved
is big and analysis requirements are computationally intensive. The system consists of a
single node that monitors the vibration levels for the package being shipped . The device in
this system uses accelerometer and gyroscope sensor for monitoring vibration levels. The
controller serves in the sensor data to the cloud in a real time using a websocket service. The
data is stored in the cloud and also visualizing the cloud based applications . The analysis
components in the cloud can trigger alerts if the vibration level becomes greater than the
threshold.

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1.5.4 IoT Level 4

This System has multiple nodes that perform local analysis. Data is stored in the cloud and
application is cloud based as shown in fig. Level4 contains local and cloud based observer
nodes which can subscribe to and receive information collected in the cloud from IoT
devices. Level 4 IoT systems are suitable for solutions where multiple nodes are required, the
data involved in big and the analysis requirements are computationally intensive.

Example : IoT System for Noise Monitoring. The system consists of multiple nodes placed in
different locations for monitoring noise levels in an area. The nodes in this example are
equipped with sound sensors. Nodes are independent of each other. Each nodes runs its owner
controller service that sends the data to the cloud . The data is stored in cloud database. The
analysis of data collected from a number of nodes is done in the cloud. A cloud based
application is used for visualizing the aggregated data.

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1.5.5 IoT Level 5

System has multiple end nodes and one coordinator node as shown in fig. The end nodes that
perform sensing and/or actuation. Coordinator node collects data from the end nodes and
sends to the cloud. Data is stored and analyzed in the cloud and application is cloud based.
Level5 IoT systems are suitable for solution based on wireless sensor network, in which data
are high intensive.

Example :IoT system for Forest Fire Detection.

The system consists of multiple nodes placed in different locations for monitoring
temperature, humidity and CO2 levels in a forest. The end nodes in this example are
equipped with various sensors such as temperature, humidity and CO2. The coordinator node
collects the data from the end nodes and act as a gateway that provides internet connectivity
to the IoT system. The controller service on the coordinator device sends the collected data to
the cloud. The data is stores in a cloud database. The analysis of data is done in the
computing cloud to aggregate the data and make predictions. A cloud based applications is
used for visualizing the data

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1.5.6 IoT Level 6.

System has multiple independent end nodes that perform sensing and/or actuation and sensed
data to the cloud. Data is stored in the cloud and application is cloud based as shown in fig.
The analytics component analyses the data and stores the result in the cloud data base. The
results are visualized with the cloud based applications. The centralized controller is aware of
the status of all endnodes and sends control commands to the nodes.

Example weather monitoring system.The system consists of multiple nodes placed in

different locations for monitoring temperatures,humidity and pressure in an area.the end
nodes are equipped with various sensors(such as temperature,humidity and pressure).the end
nodes send the data to the cloud realtime using a websocketservice.the data is stored in a
cloud database. The analysis of data is done in a cloud to aggregate a data and make
predictions.acloud based application is used for visualizing the data.

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