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Table of contents
Functions of TCP/IP model
Network Access Layer
Internet Protocol Layer
Transport Layer
User Datagram Protocol (UDP)
Protocol for Controlling Transmission (TCP)
Application Layer
Frequently Asked Questions
What exactly is a network?
What is the significance of a computer network?
What are the differences between nodes and links?
Last Updated: Mar 27, 2024

TCP/IP Model

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In this blog, we will learn about the TCP/ICP model in computer networking and we will also learn about different layers in this TCP/ICP model.

TCP/IP is a protocol that specifies how data is sent from a sender to a receiver. Application programs first transmit messages or data streams to one of the Internet Transport Layer Protocols, such as the User Datagram Protocol (UDP) or the Transmission Control Protocol (TCP). These protocols take the data from the application, break it down into packets, add a destination address, and then send the packets to the next protocol layer, the Internet Network layer.

The Internet Network layer encapsulates the packet in an Internet Protocol (IP) datagram, adds the datagram header and trailer, determines where to deliver the datagram (directly to a destination or through a gateway), and transfers the datagram to the Network Interface layer.

Functions of TCP/IP model

The layers are as follows:

  1. Process/Application Layer
  2. Host-to-Host/Transport Layer
  3. Internet Layer
  4. Network Access Layer 
TCP/IP Model
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Network Access Layer

  • The network layer is the lowest in the TCP/IP paradigm.
  • The OSI reference model defines a network layer as a combination of the Physical and Data Link layers.
  • It defines how data should be physically sent via a network.
  • This layer is largely responsible for data transport between two networked devices.
  • This layer performs functions such as encapsulating IP datagrams into network frames and converting IP addresses to physical addresses.
  • This layer uses Ethernet, token ring, FDDI, X.25, and frame relay protocols.

Recommended Topic, Internal and External Fragmentation and Basic Networking Commands

Internet Protocol Layer

This layer performs comparable responsibilities to the OSI Network layer. It defines the protocols that control logical data transmission throughout the whole network. The primary protocols discovered at this layer are as follows:

  • The Internet Protocol (IP) is responsible for transmitting packets from a source host to a destination host based on the IP addresses in the packet headers.
  • IPs are divided into two categories: IPv4 and IPv6. The majority of websites now utilize the IPv4 protocol. However, as IPv4 addresses grow limited concerning users, IPv6 is becoming increasingly popular.
  • The Control Message Protocol (ICMP) abbreviation is Internet Control Message Protocol. It is stored within IP datagrams and is responsible for providing hosts with network issues.
  • The acronym for Address Resolution Protocol (ARP) is Address Resolution Protocol. Its purpose is to identify the hardware address of a host-based on a given IP address. The four types of ARP are reverse ARP, proxy ARP, gratuitous ARP, and inverse ARP.

Also see, Message Switching in Computer Networks.

Transport Layer

The transport layer handles data reliability, flow control, and correction as data moves over the network.

At the transport layer, two protocols are used: User Datagram Protocol and Transmission Control Protocol.

User Datagram Protocol (UDP)

  • It offers apps with complete transport layer functions.
  • It establishes an active virtual circuit between the sender and receiver during the connection.
  • The User Datagram Protocol detects the issue, and the ICMP protocol notifies the sender that the user datagram has been damaged.
  • The following are the fields that make up UDP:
    The address of the application software that created the message is the source port address.
    The address of the application program that receives the message is the destination port address.
    The total length (in bytes): The entire amount of bytes in the user datagram is specified here.
    A checksum is a 16-bit field used to detect data flaws.
  • UDP does not specify how a packet is lost. There is no data segment ID in UDP; it just has a checksum.

Protocol for Controlling Transmission (TCP)

  • It provides entire transport layer services to applications.
  • It creates a virtual circuit between the sender and receiver that stays active during the connection.
  • TCP is a trustworthy protocol since it detects mistakes and retransmits the corrupted frames. Consequently, all segments must be received and acknowledged before the transmission is considered complete and a virtual circuit is erased.
  • TCP divides the whole message into smaller pieces known as segments at the transmitting end. Each segment carries a sequence number used to reorder the frames to reassemble the original message.
  • TCP reorders all segments according to the sequence numbers at the receiving end.

You can read related articles such as Congestion Control in Computer Networks here.

Application Layer

  • In the TCP/IP paradigm, the application layer is the uppermost layer.
  • It is in charge of high-level protocols and symbolic concerns.
  • The user may interact with the program via this layer.
  • When one application layer protocol wishes to connect with another, it sends its information to the transport layer.
  • In the application layer, there is some uncertainty. Except for those that interface with the communication system, no application may be deployed within the application layer. For instance, a text editor cannot be regarded as an application layer protocol. Still, a web browser interacts with the network via the HTTP protocol, an application layer protocol.


The following are the most common application layer protocols:

  • Hypertext Transfer Protocol (HTTP) is a protocol for transferring data over the internet. We can use this protocol to access data via the internet. It transfers data in a variety of forms, including plain text, audio, and video. Because it's efficient enough to employ in a hypertext environment with frequent leaps from one page to the next, it's dubbed a hypertext transfer protocol.
  • SNMP stands for Simple Network Management Protocol. It is a framework that uses the TCP/IP protocol stack to manage devices over the internet.
  • SMTP stands for Simple mail transfer protocol. The Simple Mail Transfer Protocol (SMTP) is the TCP/IP protocol that handles e-mail. The data is sent to another e-mail address using this protocol.
  • Domain Name System is the abbreviation for DNS. An IP address is a number that is used to identify a particular host's internet connection. People, on the other hand, prefer to use their names rather than their addresses. As a consequence, the Domain Name Mechanism (DNM) is the system that converts a name into an address.
  • TELNET stands for Terminal Network and is an acronym for it. It creates a connection between the local and distant computers so that the local terminal seems to be a remote terminal.
  • FTP stands for File Transfer Protocol. FTP (File Transfer Protocol) is a common internet protocol for transferring data from one computer to another.

You can also read about the network models in computer network and Subnetting in Computer Networks

Frequently Asked Questions

What exactly is a network?

According to Merriam Webster, a network is an informal organization or affiliation of various elements such as people, computers, radio stations, etc.
Domino's Pizza, for example, has 1232 locations throughout India. As the name implies, a computer network is a collection of peripherals or computers linked together and sharing a common communication channel to exchange various data and information.

What is the significance of a computer network?

Have you heard of the Internet, often known as the NET? I'm guessing you have since read this article on Coding Ninjas Studio while browsing the web. However, have you considered the Internet? The Internet connects all various network-enabled devices and allows them to share data and information, making computer networks an essential element of our lives and technical interviews.

What are the differences between nodes and links?

Any device that interacts in a network is referred to as a node. A node is a point of intersection in a network. It can send and receive data and information inside a network. Nodes include computers, laptops, printers, servers, modems, and other devices.
The connection between two nodes in a network is known as a link, sometimes known as an edge. It describes the kind of connection between the nodes (wired or wireless) as well as the protocols that enable one node to communicate with another.


This article discussed the introduction to the TCP/IP model briefly discussing each layer i.e. Network Access Layer, Internet Protocol Layer, Transport Layer, and Application Layer along with their responsibilities in detail.

Recommended Readings:

I hope that you must have gained some insight into this topic of Modulation and if you want to learn more then you can refer to this guided path for Computer Networks.

Do upvote this blog and thank you for reading.

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