What is the TCP/IP Model? | Layers, Structure & Functions (2024)

The TCP/IP model is a part of the Internet Protocol Suite. This model acts as a communication protocol for computer networks and connects hosts on the Internet. It is a concise version of the OSI Model and comprises four layers in its structure.

This concept of TCP/IP is not just important for people in the computer or IT fields but also is an essential part of the Computer Knowledge syllabus, included in major competitive exams.

Before, diving deep into the different aspects of the structure, refer to the table below and know about some basic and introductory features of the model:

In this article, we shall discuss in detail the different layers of the TCP/IP model along with their functions. Also, a few sample questions based on this topic have been given further below for the reference of Government exam aspirants.

To study in detail about what is a Computer Network and its different types, candidates can visit the linked article.

TCP/IP Notes PDF:-Download PDF Here

History and Development of TCP/IP Model

This protocol is a result of the research and development by the Defense Advanced Research Projects Agency (DARPA) during the 1960s. Given below are a few points which had played an important role in the advancement of the TCP/IP model:

• A two-network TCP/IP communications test was conducted between Stanford and University College London in 1975
• An important thing which resulted in promoting this model was when the US Department of Defense declared TCP/IP as the standard for all military computer networking. This was In March 1982
• In 1983, this structured protocol was adopted by ARPANET as a standard protocol
• Later on other Computer and IT companies including IBM, DEC, etc. had also adapted the TCP/IP model as their standard communication protocol
• In 1989, the University of California has accepted the TCP/IP code for public domain

Gradually, this Internet protocol suite or the TCP/IP model was accepted across the globe as a comprehensive framework for computer networking and Internet communication.

The TCP/IP model is considered to be similar to the Open Systems Interconnection Model. However, the framework and the structuring of the two was completely different and Transmission Control Protocol/ Internet Protocol was released prior to the OSI Model. For a detailed difference between the two, candidates can visit the Difference Between TCP/IP and OSI Model page.

Links to a few other fundamental topics and concepts have been given below for people to learn and understand one of the most complex, yet essential devices, which is the Computer:

Layers of the TCP/IP Model

Unlike the OSI model which comprises seven layers, the TCP/IP model is structured with four different layers. These four layers are:

1. Network Access Layer
2. Internet Layer
3. Host to Host Layer
4. Application Layer

Now, let us discuss each of these four layers in detail along with their functions as a part of the protocol architecture.

1. Network Access Layer

• This is the bottom-most layer of the TCP/IP model architecture
• It is a combination of the Data Link and Physical Layer of the OSI model
• The physical transmission of data takes place at this layer
• Once the frames are transmitted by a network, encapsulating the IP datagram into these frames is done in this layer
• Also, the mapping of IP address into physical address is done here
• Mainly, the function of this layer is to transmit the data between two devices, connected in a network

2. Internet Layer

• It is the second layer of the TCP/IP model and this layer is parallel to the Network Layer of the OSI Model, in terms of the structure
• Sending the data packets to their destination network is the main function of the Internet layer
• The logical transmission of data takes place at this level
• There are three different protocols used in this layer. These include:
  • IP: One of the most important protocols as it detects the IP address of a device which is later used for internetwork connections. It is using this protocol that the path with which the data shall be transmitted is decided. There are two common IP versions which are used, To know the difference between IPv4 and IPv6, visit the linked article.
  • ARP: It stands for Address Resolution Protocol. The physical address from the IP address can be determined using ARP.
  • ICMP: It stands for Internet Control Message Protocol and notification regarding datagram problems can be sent back to the user using this. Any issue with the network is immediately notified to the user by ICMP. It can only inform the user about the errors and cannot rectify the problem

3. Host-To-Host Layer

• This layer is parallel to the transport layer of the OSI Model
• The error-free delivery of data is the main function of this layer
• There are two main protocols present in this layer:
  • TCP: Another integral part, the Transmission Control Protocol is a reliable communication protocol. It manager the flow of data, i.e. the sequence and segmentation of the data
  • UDP: It is a connection-free protocol which makes it cost-effective but less reliable.

4. Application Layer

• The topic three layers of the OSI Model: Application, Presentation and Sessions, when combined together, they perform similar functions as the Application Layer of the TCP/IP model
• node-to-node communication based on the user-interface occurs here
• Multiple protocols are present in this layer, a few common ones have been mentioned below in brief:
  • HTTP: Hypertext Transfer Protocol is used to manage the communication between the server and web browsers
  • NTP: Network Time Protocol can set one standard time source in our computer, which enables sync between the server and the user
  • TELNET: Telecommunication Network is used to have access to files present of the Telnet network and manage them on internet
  • FTP: File Transfer Protocol, as the name suggests allows easy transferring of files

Other protocols of Application layer include Network File System (NFS), Secure Shell (SSH), Simple Mail Transfer Protocol (SMTP), Trivial File Transfer Protocol (TFTP), etc.

Sample Questions – TCP/IP Model

Since questions from this topic are asked in the Computer Awareness section of the major Government exams, candidates must be well prepared for the concept from the exam perspective as well.

Thus, to assistant candidates with their preparation, given below are a few sample questions based on the TCP/IP model, in the format of the multiple-choice questions, as asked in the final exam.

Candidates who are looking for study material and preparation strategy for the upcoming exams, they can refer to the links given below and start their preparation now:

Q 1. Which of the following is not a type of protocol under the Application Layer of the TCP/IP model?

1. IP
2. TCP
3. HTTP
4. FTP
5. TELNET

Answer: (1) IP

Solution: IP or Internet Protocol is a type of protocol in the Internet Layer of the TCP/IP model

Q 2. How many layers are there in the Transmission Control Protocol/ Internet Protocol (TCP/IP) model?

1. Six
2. Seven
3. Five
4. Four
5. Nine

Answer: (4) Four

Q 3. Which of the following is not a layer of the TCP/IP model?

1. Application
2. Host to Host
3. Internet
4. Network Access
5. Physical

Answer: (5) Physical Layer

Q 4. Data Link Layer and Physical Layer of the OSI Model combine together to _______ layer of the TCP/IP model.

1. Network Access
2. Internet
3. Host to Host
4. Application
5. None of the above

Answer: (1) Network Access

Q 5. The TCP/IP model was also known as the _______ model.

1. PoP
2. DoD
3. FoF
4. NoN
5. SoS

Answer: (2) DoD

Solutions: It was known as the DoD model based on the Department of Defense which helped in its development

Q 6. _____ is another name for an IP packet.

1. Datagram
2. Segment
3. Protocol
4. Department
5. Address

Answer: (1) Datagram

Questions based on similar format and a bit more complex may be asked in the upcoming competitive exams.

TCP/IP Notes PDF:-Download PDF Here

Candidates must go through the information given in this article carefully as it will enhance their knowledge as to how a computer network functions and what is the role of such structured models in networking.

For any further exam updates, study material, preparation notes, etc., candidates can turn to BYJU’S and learn from experts.