Priya

In the previous tutorial, features, advantages and limitations of TCP/IP Protocol were discussed. Though, TCP/IP is not best suited for IoT applications due to packet overheads, still being the most common protocol stack on internet, it offer ubiquitous connectivity. An IoT device can be made to communicate with a cloud or server using TCP/IP protocol without any hassle of network programming and network administration. In this project, an IoT device will be designed that could transmit sensor data to ThingSpeak Platform using the TCP/IP protocol.  

Security is a prime concern in any IoT application development. The data from the IoT devices is passed to the server/cloud where it may be stored temporarily or for long time to generate analytics. The transportation medium through which the data is passed from the IoT device to the cloud must be secured with implementation of various IoT security measures, so that the data could not be hacked by any Man-in-the-Middle attack.  

The sensors and actuators have an important role in IoT. It the sensors and actuators that enable IoT devices to interact with the physical world. The large IoT applications like smart home, smart transportation, smart grid and many others are intelligent systems that connect the world in an automated way to ease human efforts. The collective aim of such systems is to nurture the concept of IoT which is fulfilled with the use of tiny sensors. The whole Sensor Network is tightly coupled directly or indirectly with communication Network (Internet) where intelligent monitoring, management, and data processing can be achieved via the usage of networked cloud computing devices. 

In the previous tutorial, the basics of Wireless Sensor Networks were discussed. It was mentioned that WSN can utilize many wireless standards and protocols to enable sensor communication with a cloud or server. It was also mentioned that wireless sensors communicate to a cloud or server with the help of a Gateway which performs protocol conversion for the wireless network. Zigbee is one of the standard and protocol which is generally used for WSN deployed in industrial applications.  

The Internet of Things have specific network requirements. The traditional TCP/IP protocols usually do not fit to these requirements. That is why there are many protocols designed especially to cater the requirements of IoT applications. Within the IoT domain, sensor networks are one of the applications which are designed using constraint devices and are characterized by limited network bandwidth. A variant of MQTT protocol has been designed for these networks which is called MQTT-SN (MQTT for Sensor Networks).  

File Transfer Protocol (FTP) is a standard protocol for transferring files between a client and server over an internet network. The FTP protocol was written by Abhay Bhushan (IIT Kanpur) in 1971. In 1980, a TCP/IP version of the protocol as RFC 765 was introduced which became the de facto standard worldwide. in 1998, the protocol stack was updated for IPv6 support. Within this protocol, the security features were enabled by a  TLS/SSL layers called FTP Secure (FTPS). A new secured version of FTP is also widely used called SSH File transfer protocol (SFTP). The SFTP is quite different protocol than the traditional FTPS. 

In the previous tutorial, it was seen how FTP protocol can be used to update application software on an IoT device. However, FTP protocol has some security concerns as it is vulnerable to several kind of attacks like Brute force attack, FTP bounce attack, Packet capture, Port stealing (guessing the next open port and usurping a legitimate connection), Spoofing attack, Username enumeration etc. Therefore, secure variants of FTP protocols were developed. SSH File Transfer Protocol is one of the secure variants of the FTP protocol.   

Emails are the most commonly used communication in the today’s digital era. The emails can also be way of communication with IoT devices. The emails can be used to pass commands to IoT devices. The devices can then be programmed and configured to read emails received and act accordingly. There can be interesting applications built this way. For receiving emails, the IoT devices need to configure as an Email Client. They can retrieve emails only over a standard email protocol. Internet Message Access Protocol (IMAP) is one of the standard email message protocols.  

The IoT devices have very limited resources like they have embedded processors or controllers, limited RAM and ROM and they need to operate on battery without replacement for weeks, months or even years. Even they have to communicate data swiftly though small in amount but on limited network bandwidth.  

Transmission Control Protocol (TCP) is a transport layer or routing protocol. The Internet Protocol (IPv4 and IPv6) is a network layer or adaption layer protocol. Often TCP and IP are quoted together as TCP/IP. This quotation actually refers to communication of these two protocols. The TCP and IP are two separate protocols operating at different TCP model layers and OSI levels.   

In the previous tutorial, the Ethernet technology was used to connect an Arduino based IOT device with the internet network. The IOT devices can also be connected to internet network using mobile technologies like GSM, CDMA and GPRS. There are two major technologies for data transfers over cellular networks – GSM and GPRS. These two technologies differ from each other on the basis of data rates and the charges they take for their operation. 

In the previous tutorials, the IOT devices designed were connecting with the internet network via Wi-Fi. Wi-Fi is a wireless standard. It is commonly used to provide data communication among mobile devices and the internet network. Another common standard used for networking devices and computers is Ethernet.   Ethernet is most commonly used Local Area Network (LAN) technology. It provides a wired communication to connect the devices to the Internet. 

Suppose, one has a home automation system installed which can be accessed from a mobile device. That is a great power as the user can access the electronic appliances and various common household commodities imparted intelligence through embedded electronics from anywhere and anytime. What about the same home automation system is unethically hacked by someone and out turn to be a means for theft in the house. Here the glorious concept of IOT comes with a caution – ‘Security’ 

In the previous tutorial, the application layer protocols were discussed. With that discussion, the necessary foundation to understand the communication network in IOT was covered. This tutorial will discuss the other end of the IOT system that lies opposite to the device nodes. That is the ‘cloud’. IOT is lot about integrating embedded electronics and IT services. This isn’t possible without the cloud. The cloud is the soul of any IOT system. 

Application layer refers to OSI Level 5, 6 and 7. It is application layer in the TCP-IP model. In IOT architecture, this layer lies above the service discovery layer. It is highest layer in the architecture extending from the client ends. It is the interface between the end devices and the network. This layer is implemented through a dedicated application at the device end. Like for a computer, application layer is implemented by the browser. It is the browser which implements application layer protocols like HTTP, HTTPS, SMTP and FTP. Same way, there are application layer protocols specified in context to IOT as well.

In the previous tutorial, various physical and media access control (MAC) protocol for Personal Area Network (PAN), Home Area Network (HAN) and Local Area Network (LAN) were discussed. In this tutorial, physical and MAC protocols based on RFID and mobile standard will be discussed.