What are protocols?

A network protocol is a collection of rules that governs the exchange of data between devices connected to the same network. In other words, network protocols are rules that specify how devices communicate or transfer data over a network. The sender and receiver systems must obey the standards to facilitate communication between them.

TCP/IP

TCP/IP is an abbreviation that stands for Transmission Control Protocol/Internet Protocol. It is a set of layered protocols used for Internet communication in which the lower layers support the higher layers in TCP/IP.

This model follows the client-server approach. The client is the computer that sends a request to the server computer in the network.

Layers in TCP/IP

TCP/IP consists of a set of five layers that are not necessarily interdependent. Each layer has specific functionality, which is explained in detail below:

1. Physical network layer- It specifies the characteristics of the hardware to be used for the network. It consists of all the functions required to transmit a bit stream from one physical medium to another.
2. Data-link layer - It is where the actual data transfer in bits occurs. It uses the destination address supplied by the network layer. The layer arranges the bit stream into a data unit, named frame, and transfers the frame to another system.
3. The Internet Protocol (IP) layer− It is used for the transmission of data chunks across network borders. This layer uses the Internet Protocol (IP). The goal of IP is to deliver packets only based on IP addresses mentioned in the packet headers from the source to the destination host.
4. Transport layer− It is responsible for providing in-order delivery of messages from a source application to a destination application. It is responsible for end-to-end delivery. The transmission control protocol (TCP) and user datagram protocol (UDP) are the protocols used in the transport layer.
5. Application layer− It is the highest level of this protocol suite. It interacts with the software application to provide a communicating component. This layer is the closest to the end-users. It facilitates node-to-node session delivery or data transfer between users. Some protocols that work in this layer are Hypertext transfer protocol (HTTP), File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP), Domain Name System (DNS), Teletype Network (TELNET), and so forth.

Types of network protocols

Network protocols can be divided into three major types:

1. Network communication protocols
2. Management protocols
3. Security protocols

Network communication protocols

Network communication protocols are crucial for network functioning. These protocols represent the format and rules through which data transfer is done in a network. They are also responsible for authentication, synchronization, error detection, and semantics. Some communication protocols include:

• The Hypertext Transfer Protocol (HTTP)- This protocol is an application layer protocol that allows browser and server communication. The worldwide web uses this protocol to handle communication between web browsers and servers.
• The Transmission Control Protocol (TCP)– It is a reliable, connection-oriented service that delivers data packets in proper sequence. In other words, TCP creates a logical connection between the server and client system and sends packets using this connection. 
• The User Datagram Protocol (UDP)– It is an unreliable, connectionless service that does not deliver data packets in an ordered sequence. In other words, UDP does not establish a connection for sending packets over a network.
• Internet Relay Chat (IRC) - IRC is a text-based protocol. This protocol allows communication in the form of text. It uses software systems to communicate with the server and send messages to client systems.
• The File Transfer Protocol (FTP)– This protocol allows file transmission from one system to another over a network. It can continue file transfer sessions even if the connection is lost provided the protocol is properly configured

Network Management protocol

Network management protocols identify the policies and processes for handling and maintaining the computer network. They ensure stable communication and peerless performance throughout the network. These protocols are also used to troubleshoot connection issues in client and server systems. Types of network management protocols are as follows:

• Simple Network Management Protocol (SNMP)- SNMP monitors and handles network devices. It collects information by checking all the devices in the network at a fixed time interval.
• Internet Control Message Protocol (ICMP)- ICMP is used to inform hosts about issues in the network. This protocol sends error messages to report connectivity problems between devices in the network.

Security protocols

Security protocols ensure safe and secure data transfer in the network. They define how the data is secured during its transmission. This ensures that no unauthorized users, services, or devices access the data transmitted on the network. These protocols use cryptography and encryption to secure data. Commonly used security protocols include:

• Secure Socket Layer (SSL)- SSL is used to ensure secure internet connectivity and sensitive data protection. It encrypts the data transferred from the client to the server or server to server systems.
• Secure File Transfer Protocol (SFTP)- This protocol secures the file transferred over a network. The data transferred through the network is encrypted.
• Secure Hypertext Transfer Protocol (HTTPS)- HTTPS is a secured version of HTTP. It is a combination of HTTP and SSL protocols. That means this protocol secures data transferred between the browser and server by encrypting it. This protocol is mainly used when the browser asks users to sign in, fill forms, or perform bank transactions.
• Secure Shell (SSH)– It is a security protocol used to encrypt a connection and maintain it. This protocol establishes a secure session over a TCP/IP connection.

Context and Applications

The subject is important in high school, undergraduate, graduate level, and all the entrance exams relating to Computer science or Information Technology field, particularly for:

• Bachelors in Network Communication
• Bachelors in Computer Science
• Masters in Computer Science

Practice Problems

Q1. What are network protocols?

1. Set of rules
2. Set of malpractices
3. Set of databases
4. Helps in managing the organization

Answer- a

Explanation-Network protocols are a collection of rules that governs the exchange of data between devices connected to the same network.

Q2. What is the full form of FTP?

1. Formation transport layer protocol
2. Formation transmission protocol
3. File transfer protocol
4. File transmission protocol

Answer-c

Explanation- FTP stands for file transfer protocol.

Q3. What is the elementary function of the transport layer?

1. Point-to-point telecommunications
2. End to end delivery
3. Synchronization of common network protocols
4. Updating and maintaining IP addresses

Answer- b

Explanation- The transport layer is responsible for end-to-end delivery.

Q4. Which protocol is used to secure file transmission?

1. Telnet
2. SMTP mail server
3. SFTP
4. HTTP remote computer

Answer-c

Explanation- SFTP protocol is used for transferring files securely over a network.

Q5. What is the first layer of the TCP/IP model?

1. Router higher-level layer
2. IP addresses layer
3. ITU-T common protocols layer
4. Physical layer

Answer-d

Explanation- Physical layer is the first and foremost layer of TCP/IP.

Common Mistakes

Students are generally confused between different protocols used in different layers of the TCP/IP model. They may know the usage of different protocols, but why that particular protocol is used in that specified layer of TCP/IP is quite confusing for them.

Related Concepts

• Foundations of networking (Switches, routers, and wireless access points)
• Types of Networks (LAN, MAN, WAN)
• Types of topologies (Star, Bus, Ring, Mesh)
• Unique Identifiers of network
• Data Transmission
• Wired and Wireless Communication Medium