What are Network Protocols?
Network protocols are a collection of rules, conventions and data formats that govern the way devices share data across networks. Computer networks wouldn’t exist without all these protocols.
Before we dive into network protocols, let’s first understand what OSI Model is.
What is the OSI Model? How does it work?
OSI (Open Systems Interconnection Model) is a seven-layer conceptual structure which explains how a network or telecom system works. The OSI Model explains how a network works and how it interacts with other networks. Each layer is self-contained and can complete the tasks assigned to them on their own.
The communication mechanism between two network devices is separated by the seven layers of OSI Model. Here is a diagram showing the interaction between two network devices following the OSI Model.

Network protocols are a way to separate the communication mechanism from the tasks at each layer of the OSI Model. One or more network protocols can be used at each layer of data exchange.
Network Protocol Characterization
Now that you have an understanding of how the OSI model works let’s move on to protocol classification. These protocols are the most commonly used in communication networks.
Protocols for Application Layer Network Protocols
1. HTTP (Hypertext Transport Protocol): HTTP allows you to access resources such as HTML documents. It is the backbone for all data exchanges on the Internet. It was created to allow communication between web browsers, and servers. HTTP Requests allow clients to communicate with web servers.
HTTP port No – 80

2. HTTPS (Hypertext Transport Protocol Secure): HTTPS is a secure variant of HTTP. This protocol is used to transfer data between your browsers and the website you are visiting. HTTPS protocol allows website visitors to securely transfer sensitive information, such as login information, bank details, credit card details, and bank details, over the internet. It is protected by TLS (Transport Layer Security) and SSL (Security Sockets Layer).
HTTPS port no – 443

3. FTP (File Transport Protocol: File Transfer Protocol) is a common protocol for sharing information between computers on a TCP/IP-based network such as the Internet. FTP allows users to transfer data between systems.
Port no. 21 and 20
4. Telnet (Terminal Emulation Protocol): Telnet allows users to connect to remote computers and communicate with them. Network administrators typically use Telnet for remote computer control and connection. First, a Network Administrator must input the IP address or hostname of the remote device. After that, they will receive a virtual terminal that allows them to communicate with the host.
Telnet port no – 23

5. DNS (Domain Name System protocol: DNS is the Internet’s phone book. Domain names are used to access online data. Web browsers use Internet Protocol (IP), addresses to communicate. DNS protocol translates domain names into IP addresses.
Every internet-connected device has an unique IP address, which other devices use for its location. DNS servers have made it possible for humans to forget IP addresses.
(Example – www. (Example – www.
Port no – 53

6. DHCP (Dynamic Host Configuration Protocol): This is a protocol for network management that assigns an IP address (or IP address) to any device or node in a network to allow them to communicate via IP (Internet Protocol). These settings can be automated and centrally managed by DHCP. It is not necessary to manually delegate IP addresses to new computer.
APIPA (Automatic Private IP Addressing), is an acronym for Automatic Private IP Addressing. If a DHCP server (Dynamic Host Configuration Protocol) is unavailable,