Network Protocols

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Until now, we’ve only mentioned protocols in passing. However, we did not fully explain protocol. Simply because we lack the necessary knowledge to comprehend the concept. In this tutorial, we will go over protocol in great detail. This tutorial is most likely the most important in the series.

A protocol is a set of rules for formatting and processing data in networking. You can treat computer protocols as a common language for computers. Although the computers in a network may use very different software and hardware, the use of protocols allows them to communicate with one another.

Essentially, it enables connected devices to communicate with one another regardless of differences in internal processes, structure, or design. Without network protocols, we would be unable to communicate with people all over the world. Network protocols are essential in modern digital communication.

Network protocols are important for more than just certified network specialists and IT professionals. Whether they realize it or not, billions of people use network protocols every day.Every time you connect to the internet, you are utilizing network protocols. Though you may not understand how network protocols work or how frequently you encounter them, they are required for any use of the internet or digital communications.

Why Do We Need Protocols For Communication?

Protocols are rules for how to behave. They are nothing more than that. We use protocols all the time, even when we aren’t aware of it.

Language is an example of a protocol. Your question was asked in English, which we read and responded to in English. But what if we assumed your question was being asked in "terrible french"?

Suddenly, your question is meaningless. The words are not actual words. We will be unable to answer your question because we did not understand what you wanted to know.  It’s completely incomprehensible. What if we didn’t recognize it as language at all? What if we asked a question that seemed completely rational to us? It went something like this: $hq@q29085f(* 04y5U(7as’ ‘.

How would you respond? You couldn’t because you have no idea what we are asking, or if it’s even a question.

That is why communication protocols are essential. They give meaning and procedure to what we say, write, and do. If you don’t understand the protocol, you may misinterpret the entire communication.

The concept is the same for network protocols. What happens if we send a random bit pattern across the wire? Nothing positive. None of the other equipment on that wire will understand what we are saying. It will not be recognized as useful. This is due to the fact that it does not follow any protocols(defined set of rules).

There are protocols for everything in networking. What is the voltage of a 0? What is the voltage of a 1? Are we defining those values based on voltage(we are not in wireless or fiber optic networks)?  What makes a frame unique? What exactly is a packet? What defines the source and destination addresses? All of these things, and many more, must be defined in order for communication to take place.

So, why do protocols for communication exist? Because communication is impossible without them.

Network protocols deconstruct large-scale processes into small, specific tasks or functions. This happens at every level of the network, and each function must work together at every level to complete the larger task at hand. The term protocol suite refers to a collection of smaller network protocols that work together.

Network protocols are typically developed by various networking or information technology organizations in accordance with industry standards.

The following organizations have defined and published various network protocols:

While network protocol models are generally similar, each protocol is unique and operates in the manner specified by the organization that created it.

List Of Network Protocols

There are thousands of different network protocols, but they all perform one of three primary actions:


Network management


Communication Protocols

As we have previously mentioned, communication protocols enable network devices to communicate with one another. They are used in both analog and digital communications and can be used for a variety of tasks ranging from file transfer between devices to internet access.

The following are examples of common communication protocols:

Automation Protocols: These protocols are used to automate various processes in both commercial and personal settings, such as smart buildings, cloud computing, and self-driving cars.

Instant Messaging Protocols: A variety of instant messaging network protocols enable instantaneous, text-based communications on smartphones and computers.

Routing Protocols: Routing protocols allow routers and other network devices to communicate with one another. There are also routing protocols that are designed specifically for ad hoc networks.

Bluetooth Protocols: Bluetooth devices, such as headsets, smartphones, and computers, function thanks to a variety of Bluetooth protocols.

File Transfer Protocols: File transfer protocols(FTP) are used whenever files are transferred from one device to another, whether through a physical or digital medium.

Internet Protocols: Internet Protocol (IP) allows data to be sent between devices over the internet. Without IP, the internet could not function as it does today.

Network Management Protocols

Network management protocols define and describe the various procedures required to operate a computer network effectively. These protocols have an impact on various devices on a single network, such as computers, routers, and servers, to ensure that each one, as well as the network as a whole, performs optimally.

The following are the functions of network management protocols:

Connection Protocols: These protocols establish and maintain consistent connections between devices on the same network.

Link Aggregation Protocols: Link aggregation protocols enable you to combine multiple network connections into a single link between two devices. This improves the connection’s strength and helps it stay connected if one of the links fails.

Troubleshooting Protocols: Troubleshooting protocols enable network administrators to identify network errors, evaluate the quality of the network connection, and determine how to resolve any issues.

Security Protocols

Security protocols, also known as cryptographic protocols, work to protect the network and the data transmitted over it from unauthorized users.

The following are common functions of security network protocols:

Encryption Protocols: Encryption protocols safeguard data and secure areas by requiring users to enter a secret key or password to access that information.

Entity Authentication Protocols: Entity authentication protocols establish a system in which different devices or users on a network must verify their identity before accessing secure areas.

Transportation Security Protocols: Transportation security protocols safeguard data as it travels from one network device to another.

You’ve almost certainly encountered network protocols when using electronic devices, whether you realize it or not – and some of them are easily identifiable.

Here are some of the most commonly used network protocols:

Hypertext Transfer Protocol (HTTP): The Hypertext Transfer Protocol (HTTP) defines how data is transmitted over the internet and how web servers and browsers should respond to commands. This protocol (or its secure counterpart, HTTPS) can be found at the beginning of many URLs or web addresses on the internet.

Secure Socket Shell (SSH): This protocol allows secure access to a computer even if it is connected to an unsecured network. SSH is especially useful for network administrators who need to remotely manage multiple systems.

Short Message Service (SMS) Protocol: This communication protocol was designed to send and receive text messages over cellular networks. SMS only refers to text-based messages. Multimedia Messaging Service (MMS), an extension of the SMS protocol, is required for images, videos, and other media.

Network protocols define how devices and processes interact with one another, not just how they work separately. Without these predetermined conventions and rules, the internet would lack the infrastructure required for it to be functional and usable. Network protocols are the bedrock of modern communications; without them, the digital world would collapse.

If you need detailed information about any protocol, the definitive source is the standards document for the protocol. Although there are numerous standards organizations around the world, the Internet Engineering Task Force (IETF) and the World Wide Web Consortium(W3C) are the two that produce the majority of the standards relevant to application layer network programming and protocols. The IETF is a relatively informal, democratic body that welcomes participation from anyone who is interested. Its standards are based on “rough consensus and running code,” and its implementations tend to follow rather than lead. TCP/IP, MIME, and SMTP are examples of IETF standards. The W3C, on the other hand, is a vendor organization controlled by dues-paying member corporations that explicitly prohibits individual participation. For the most part, the W3C attempts to define standards prior to implementation. HTTP, HTML, and XML are all W3C standards.

IETF standards and near-standards are published as Requests for Comments (RFCs).  A published RFC, despite its name, is a completed work. It may become obsolete or be replaced by a new RFC, but it will not be altered. “Internet drafts” are IETF working documents that are subject to revision and open for development.

RFCs range from general-interest informational documents to detailed specifications of standard Internet protocols like FTP. RFCs can be found in a variety of places on the Internet, including and RFCs, for the most part (especially standards-oriented RFCs), are highly technical, turgid, and nearly incomprehensible. Nonetheless, they are frequently the only complete and trustworthy source of information about a specific protocol.

Most RFC proposals begin with an idea and the creation of a prototype by an individual or group. The prototype is very important. Before something can become an IETF standard, it must first exist and function. Unlike standards promulgated by other organizations, this requirement ensures that IETF standards are at least feasible.

The RFCs that provide formal documentation for the protocols discussed in this tutorial are listed below.

RFC 791, RFC919, RFC922, RFC 950Internet ProtocolThe IP internet layer protocol.
RFC 768User Datagram ProtocolAn unreliable, connectionless transport layer protocol.
RFC 792Internet Control MessageProtocol (ICMP)An internet layer protocol that uses raw IP datagrams but is not supported by Java.Its most familiar uses are ping and traceroute.
RFC 793Transmission ControlProtocolA reliable, connection-oriented, streaming transport layer protocol.
RFC 2821Simple Mail TransferProtocolThe application layer protocol by which one host transfers email to another host.This standard doesn’t say anything about email user interfaces; it covers themechanism for passing email from one computer to another.
RFC 959File Transfer ProtocolAn optionally authenticated, two-socket application layer protocol for file transferthat uses TCP.
RFC 1034,RFC 1035Domain Name SystemThe collection of distributed software by which hostnames that human beings canremember, like, are translated into numbers that computers canunderstand, like This RFC defines how domain name servers ondifferent hosts communicate with each other using UDP.
RFC 1945Hypertext Transfer Protocol(HTTP 1.0)Version 1.0 of the application layer protocol used by web browsers talking to webservers over TCP; developed by the W3C rather than the IETF.
RFC 2616Hypertext Transfer Protocol(HTTP 1.1)Version 1.1 of the application layer protocol used by web browsers talking to webservers over TCP.
RFC 826Address Resolution ProtocolThe purpose of this RFC is to present a method of ConvertingProtocol Addresses (e.g., IP addresses) to Local NetworkAddresses (e.g., Ethernet addresses).

In this course, we will go over some of these protocols in great detail.

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