Communication Protocols in Networking

A protocol is a set of rules that govern how a network operates.

The protocol specifies standardized formats for data packets, as well as techniques for detecting and correcting errors.

A protocol is essentially a formal description of message formats and the rules that two or more machines must follow in order to exchange messages.

Assume there are two people, Person A and Person B, to better understand the concept of communication protocol. Assume that Person A and Person B need to talk to each other in order to exchange ideas. However, it turns out that both Persons A and B are egoists. They begin talking again at the same time, pause for a breath, and then resume talking. Consider the confusion and chaos. To avoid it, they must adhere to a set of rules when conversing with one another. For example, suppose Person A must speak first, then allow Person B to present his or her ideas, and so on. This shared set of rules is referred to as the communication protocol for Person A and Person B.

Every time we want to do something on another computer, we need protocols. We need protocols every time we want to print something on a network printer.

Every time we want to download a file, we must follow protocols. We don't need protocols every time we want to save our work to disc, unless the disc is on a network file server.

In most cases, multiple protocols will be in use at the same time. For one thing, computers typically perform multiple tasks at once, and frequently for multiple people. As a result, most protocols allow for multitasking.

A single operation may involve multiple protocols. Consider the NFS protocol (which stands for "Network File System"). An NFS operation is used to write to a file, which uses another protocol to perform a function call on a remote host, another protocol to deliver a datagram to a remote host's port, another protocol to deliver a datagram over Ethernet, and so on.

Here is a list of some of the most important and widely used protocols, which will be covered in more detail in subsequent sections:

You will learn about the communication protocols listed above one by one, in sections. Let's begin with HTTP.


The Hypertext Transfer Protocol, more commonly known as HTTP, is an application-level protocol that possesses the lightness and speed required for distributed collaborative hypermedia information systems.

The Hypertext Transfer Protocol (HTTP), which enables the construction of systems without regard to the data being transferred, includes the type of data representation as one of its components.

Since its inception in1990, the global information initiative known as the World Wide Web has made use of HTTP.

On the World Wide Web, the set of rules known as HTTP governs the transfer of hypertext in the form of text, graphics, images, sound, and video, among other things (World Wide Web).

Information systems that are actually useful need to have more features than just the ability to retrieve data. These features should include search, front-end update, and annotation. When a request is made, an open-ended set of methods can be used to indicate what the request is for using HTTP. It uses the Uniform Resource Identifier, also known as a URI, as a location, also known as a URL, or as a name, also known as a URN, to point to the resource on which a method is to be used.

When messages are sent to HTTP, they are in a format that is comparable to what is used by Internet Mail and MIME (Multipurpose Internet Mail Extensions).

HTTP is also used as a generic protocol for communication between user agents and proxies or gateways to other Internet protocols such as SMTP, NNTP, FTP, Gopher, and WAIS. This allows for basic hypermedia access to resources that are made available from a variety of applications and simplifies the implementation of user agents.

The HTTP protocol is made up of two components that can be considered fairly independent of one another:

  • the set of requests from browsers to servers
  • the set of responses received in return

Although it was intended for use on the web, the Hypertext Transfer Protocol (HTTP) has been made purposefully more general than is strictly required with an eye toward the development of object-oriented programs in the future.

Users are able to read a web page, read the header of a web page, store a web page, append a web page to a named resource, remove a web page, connect two resources that already exist, or break an existing connection between two resources by utilizing one of the many built-in request methods that are included with HTTP.


The term "File Transfer Protocol" refers to an industry standard that facilitates the transfer of files between computers using the internet.

You could also say that File Transfer Protocol (FTP) is one of the first services that was available on the Internet and was designed to enable users to move files from one computer to another.

Transferring files of any format is possible; however, you may be required to specify whether the file in question is an ASCII or binary file. They are able to be transferred to any system that is connected to the Internet so long as the appropriate permissions are in place.

Advantages of FTP

The following is a list of some of the most significant benefits that FTP provides:

  • When moving files from one network in an organization to another, the File Transfer Protocol (FTP) is an extremely helpful tool.
  • FTP is an efficient tool for facilitating collaboration between members of a group who are located in different parts of the world.
  • The File Transfer Protocol (FTP) is a powerful and widely used method for exchanging data over the internet.

Objectives of FTP

The File Transfer Protocol (FTP) is designed to accomplish the following primary goals:

  • to encourage the sharing of files among users.
  • to encourage the use of remote computers either indirectly or implicitly.
  • to protect a user from the fact that different hosts use different file storage systems.
  • to transfer data in a dependable and productive manner. Even though a user can access FTP directly from a terminal, the protocol was primarily developed for use by computer programs.


The acronym TCP refers to the Transmission Control Protocol, while the acronym IP refers to the Internet Protocol. TCP/IP is a set of protocols that is organized in layers.

The fundamental mode of communication used by the Internet is known as TCP/IP. The Internet Protocol, or IP, component of TCP/IP makes use of numeric IP addresses to join network segments. The Transmission Control Protocol, or TCP, component of TCP/IP ensures the reliable delivery of messages between computers that are connected via a network.

Simply focusing on this example will help you grasp the concept of TCP/IP. Sending mail is an example of a common situation. Then to begin, there is a standard procedure for sending mail. This defines a set of commands that one machine sends to another machine, such as commands to specify who the sender of the message is, to whom it is being sent, and then the actual text of the message itself. For example, these commands could be: On the other hand, this protocol works under the assumption that there is a dependable method of communication between the two computers. In the same way that other application protocols define a set of commands and messages to be transmitted, mail does the same thing. It is compatible with Internet Protocol (TCP) and TCP. TCP is the protocol that is accountable for ensuring that the commands are sent to the other end successfully. It monitors what is sent and resends anything that was unsuccessful in making it through the first time. If a message is too large to fit in a single datagram, such as the body of an email, the Transmission Control Protocol (TCP) will break it up into multiple datagrams and ensure that each one arrives in the correct format. Because these functions are required by a wide variety of applications, they are not included in the specifications for the process of sending mail; rather, they are grouped together into a separate protocol.

Having said that, there are a few services that each and every application requires. As a result, all of these services are combined into a single IP. Similar to TCP, Internet Protocol (IP) can be conceptualized as a library of routines that are utilized by TCP but are also made accessible to applications that do not make use of TCP. Layering is the term used to describe the strategy of building multiple levels of protocol.

Applications that use TCP/IP typically make use of the following four layers:

  • an application protocol such as email
  • a protocol such as TCP that supplies services required by numerous applications
  • n Internet Protocol that supplies the fundamental service of delivering datagrams to their intended location
  • the protocols that are necessary for the management of a particular physical medium, such as Ethernet or a point-to-point line


The abbreviations SLIP and PPP refer to the Serial Line Internet Protocol and the Point-to-Point Protocol, respectively, used in SLIP/PPP.

It is possible to say that SLIP is utilized for the purpose of delivering IP packets over dial-up lines, whereas PPP is utilized for the purpose of transmitting IP packets over serial lines.


The first protocol for relaying IP packets over dial-up lines was called Serial Line Internet Protocol. It primarily defines an encapsulation mechanism, but it also does a few other things. It is not possible to test links, assign addresses on the fly, or use different protocols on the same link at the same time. PPP has largely taken the place of SLIP in recent years.


The protocol known as Point-to-Point Protocol is the Internet standard for transmitting IP packets over serial lines.

PPP is the solution that is currently considered to be the most effective for dial-up Internet connections, including ISDN.

PPP is a multi-layered protocol, and the first layer consists of a Link Control Protocol (LCP) that handles link configuration, testing, and establishment. After the LCP has been initialized, a single NCP (Network Control Protocol) or multiple NCPs (Network Control Protocols) from a set of available options can be used to transport traffic for a specific protocol suite.

IP packets can be transmitted across a PPP link using the IPCP, which stands for the IP Control Protocol.

PPP is capable of supporting synchronized and unsynchronized lines simultaneously.

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