It is the network layer communication protocol. Its routing function enables inter-networking and essentially establishes the Internet Protocols means “A set of rules usually in the form of a code that describes the expected behavior”

Importance of Protocols

Internet protocols matter because they form the foundation of all digital communication over networks, Including the Internet. Their main role is to monitor how data is transmitted, received, and interpreted, ensuring that different devices and systems can work together seamlessly.

OSI Model

The Open Systems Interconnection (OSI) model is a model created by the International Organization for Standardization. It allows different communication systems to interact using standard protocols. The OSI Model can be thought of as a universal language for computer networking. It is based on dividing a communication system into seven abstract layers, each building on the previous one. Let’s see the Layers one by one

1. Physical Layer

   These layers work on bits i.e. 0 and 1. It is responsible for data transfer by wires and cables. data is converted into bit streams.

   

2. The Data Link Layer

   This layer works on frames. It is similar to the network layer. The data link layer takes the packets from the network layer and breaks them into smaller pieces called “Frames”.

   

3. The Network Layer

   The network layer is responsible for transferring data between two different devices. If 2 devices are on the same network then the network layer is unnecessary. If both devices are on different networks, then the network layer becomes useful. From the upper layer network layer takes segments and breaks them into Packets. It finds the best physical path for data transferring which is known as routing.

   

4. The Transport Layer

   Transport Layer is responsible for end-to-end communication between two devices. This includes taking data from the Session layer dividing the data into segments and then sending it to the Network Layer. This layer is responsible for flow control and error control. Transport Layer includes Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

   

5. The Session Layer

   This layer is responsible for starting and ending communication between two devices. The period from when communication starts to when it ends is called the session. The session layer makes sure the session stays open long enough to transfer all the data being exchanged, and then it quickly closes the session to avoid wasting resources.

   

6. The Presentation Layer

   This layer mainly prepares data for use by the application layer; in other words, layer 6 makes the data ready for applications to use. The presentation layer handles the translation, encryption, and compression of data.

   When two devices communicate, they might use different encoding methods, so layer 6 translates incoming data into a format that the application layer of the receiving device can understand.

   

7. The Application Layer

   This is the only layer that directly interacts with data from the user. Software applications like web browsers and email clients rely on the application layer to initiate communications.

   

Protocols

Let’s see some common protocols

1. HTTP

   Hypertext Transmission Protocol or HTTP is the foundation of the Internet Protocol Suite. Text which contains links to other texts is called an HTTP. It is a human-readable data. HTTP is a stateless protocol means every time you visit a page, you are a new user. No memory of previous requests stores. It is the foundation of data communication. there is also a version 2 and 3 of HTTP. version 2 is called HTTPS as ‘S‘ means Secured. In HTTPS TLS handshake takes place. It is said that around 80% of the world’s websites run on HTTPS. HTTP 3 is the successor of HTTP 2. HTTP 3 uses QUIC instead of TCP protocol. Around 30% of the world’s websites run on HTTP 3.

2. HTTPS

   Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It uses encryption for secure communication over a computer network and is widely used on the Internet.[1][2] In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS) or, formerly, Secure Sockets Layer (SSL). The protocol is therefore also referred to as HTTP over TLS,[3] or HTTP over SSL.

3. TCP

   The Transmission Control Protocol (TCP) is one of the main protocols in the Internet protocol suite. It started with the initial network setup, where it worked alongside the Internet Protocol (IP). This is why the whole suite is often called TCP/IP. TCP ensures reliable, ordered, and error-checked delivery of data (bytes) between applications on hosts communicating over an IP network. Major internet applications like the World Wide Web, email, remote administration, and file transfer depend on TCP, which is part of the transport layer in the TCP/IP suite. SSL/TLS usually operates on top of TCP.

4. UDP

   In computer networking, the User Datagram Protocol (UDP) is one of the main communication protocols in the Internet protocol suite. It is used to send messages, known as datagrams, to other hosts on an Internet Protocol (IP) network. Unlike some other protocols, UDP does not need prior communication to establish channels or data paths within an IP network.

TCP vs UDP Protocol

TCP/IP Protocol Suite

Transmission Control Protocol (TCP) is a communication standard that allows application programs and computing devices to exchange messages over a network. It is designed to send packets across the internet and ensure data and messages are delivered successfully over networks.

TCP is one of the fundamental standards that define Internet rules and is included in the standards set by the Internet Engineering Task Force (IETF). It is one of the most commonly used protocols in digital network communications, ensuring end-to-end data delivery.

TCP organizes data for transmission between a server and a client, guaranteeing the integrity of the data communicated over a network. Before transmitting data, TCP establishes a connection between the source and destination, keeping it active until communication starts. It then breaks large data into smaller packets, maintaining data integrity throughout the process.

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