The essence of IoT is networking and for networking in IoT there are protocols that are to be followed. Or I can say technologies that you will use in IoT have a set protocol that they will use for communications.
So, What is a protocol?
In Communication a protocol is a set of rules and guidelines for transferring data. Rules are defined for each step and process during communication between two or more computers. Networks have to follow these rules to successfully transmit data.
Why a protocol?
While working on a project there are several requirements that needed to be completed like: speed, range, power, utility, discoverability ,etc. And a protocol can easily help you find a way to understand and solve the problem.
This list contains few of the IoT protocols that I think every engineer should know. These are basically wireless network protocols.
Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz) from fixed and mobile devices, and building personal area networks (PANs). Invented by Dutch electrical engineer Jaap Haartsen, working for telecom vendor Ericsson in 1994, it was originally conceived as a wireless alternative to RS-232 data cables.
ZigBee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection. Hence, ZigBee is a low-power, low data rate, and close proximity (i.e., personal area) wireless ad hoc network.
Z-Wave is a wireless communications protocol used primarily for home automation. It is a mesh network using low-energy radio waves to communicate from appliance to appliance, allowing for wireless control of residential appliances and other devices, such as lighting control, security systems, thermostats, windows, locks, swimming pools and garage door openers.
Like other protocols and systems aimed at the home and office automation market, a Z-Wave automation system can be controlled from a wireless key fob, a wall-mounted keypad or through smartphones, tablets or computers, with a Z-Wave gateway or central control device serving as both the hub controller and portal to the outside. It provides interoperability between home control systems of different manufacturers that are a part of its alliance. On May 2017, there were over 1,700 interoperable Z-Wave products. As of April 18, 2018, there were over 2,400 interoperable Z-Wave products.
A very new IP-based IPv6 networking protocol aimed at the home automation environment is Thread. Based on 6LowPAN(number 9 on this page), and also like it, it is not an IoT applications protocol like Bluetooth or ZigBee. However, from an application point of view, it is primarily designed as a complement to Wi-Fi as it recognises that while Wi-Fi is good for many consumer devices that it has limitations for use in a home automation setup.
Wi-Fi is a technology for wireless local area networking with devices based on the IEEE 802.11 standards. Wi-Fi is a trademark of the Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing.
Devices that can use Wi-Fi technology include personal computers, video-game consoles, smartphones and tablets, digital cameras, smart TVs, digital audio players and modern printers. Wi-Fi compatible devices can connect to the Internet via a WLAN and a wireless access point. Such an access point (or hotspot); has a range of about 20 meters (66 feet) indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points.
LoRaWAN is a media access control (MAC) protocol for wide area networks. It is designed to allow low-powered devices to communicate with Internet-connected applications over long range wireless connections. LoRaWAN can be mapped to the second and third layer of the OSI model. It is implemented on top of LoRa or FSK modulation in industrial, scientific and medical (ISM) radio bands. The LoRaWAN protocols are defined by the LoRa Alliance and formalized in the LoRaWAN Specification which can be requested on the LoRa Alliance website.
Near-field communication is a set of communication protocols that enable two electronic devices, one of which is usually a portable device such as a smartphone, to establish communication by bringing them within 4cm (1.6 in) of each other.
These devices are used in contactless payment systems, similar to those used in credit cards and electronic ticket smartcards and allow mobile payment to replace/supplement these systems. This is sometimes referred to as NFC/CTLS (Contactless) or CTLS NFC. NFC is used for social networking, for sharing contacts, photos, videos or files. NFC-enabled devices can act as electronic identity documents and keycards. NFC offers a low-speed connection with simple setup that can be used to bootstrap more capable wireless connections.
IoT application that requires operation over longer distances can take advantage of GSM/3G/4G cellular communication capabilities. While cellular is clearly capable of sending high quantities of data, especially for 4G;, the expense and also power consumption will be too high for many applications, but it can be ideal for sensor-based low-bandwidth-data projects that will send very low amounts of data over the Internet. A key product in this area is the SparqEE range of products;, including the original tiny CELLv1.0 low-cost development board and a series of shield connecting boards for use with the Raspberry Pi and Arduino platforms.
A key IP (Internet Protocol)-based technology is 6LowPAN (IPv6 Low-power wireless Personal Area Network). Rather than being an IoT application protocols technology like Bluetooth or ZigBee;, 6LowPAN is a network protocol that defines encapsulation and header compression mechanisms. The standard has the freedom of frequency band and physical layer and can also be used across multiple communications platforms, including Ethernet, Wi-Fi, 802.15.4 and sub-1GHz ISM.
A key attribute is the IPv6 (Internet Protocol version 6) stack;, which has been a very important introduction in recent years to enable the IoT. IPv6 is the successor to IPv4 and offers approximately 5 x 1028 addresses for every person in the world;, enabling any embedded object or device in the world to have its own unique IP address and connect to the Internet. Especially designed for home or building automation, for example;, IPv6 provides a basic transport mechanism to produce complex control systems ;and to communicate with devices in a cost-effective manner via a low-power wireless network.
This unique approach in the world of wireless connectivity;, where there is no signaling overhead, a compact and optimized protocol;, and where objects are not attached to the network. Sigfox offers a software based communications solution;, where all the network and computing complexity is managed in the Cloud, rather than on the devices. All that together, it drastically reduces energy consumption and costs of connected devices.
SigFox wireless technology is based on LTN (Low Throughput Network). It is wide area network based technology which supports low data rate communication over larger distances. It is used for M2M and IoT applications which transmits only few bytes per day.
SigFox can be interfaced with cellular network in order to coexist with cellular wireless technologies such as GSM, CDMA, LTE etc.
There are more protocols about which I have not talked in this article like: