12 TCP/IP Interview Questions And Sample Answers (With Tips)

Updated 14 March 2023

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Transmission Control Protocol/Internet Protocol, commonly known as the TCP/IP suite, is a group of communication protocols used in computer networks. Jobs in this field often require comprehensive knowledge about TCP/IP for efficiency and success. Because of this, interviewers may ask technical and theoretical questions in an interview to assess a candidate's proficiency in TCP/IP. In this article, we outline a few TCP/IP interview questions and their sample answers and provide some interview preparation tips to increase your chances of success:

TCP/IP Interview Questions And Sample Answers

Here are some sample TCP/IP interview questions that interviewers may ask to test your understanding of foundational protocols:

1. Explain the concept of TCP/IP

Interviewers may ask this question to analyse your basic understanding of the concept. You can elaborate on the functions of TCP/IP while answering this question to convey your technical understanding.

Example: "The primary purpose of TCP/IP is to deliver data packets between the source application or the device and the destination using different methods and structures that place tags such as address information within data packets. TCP/IP helps connect devices over the Internet and to transmit data from one device to another."

2. How many layers does TCP/IP architecture have?

The architecture of the TCP/IP suite of protocols uses layers. These layers define how the information transfers from the sender to the receiver. In your answer, you can mention the five layers and briefly explain each.

Example: "TCP/IP has five layers which are the application layer, transport layer, network layer, data link layer and physical layer. The application layer is when the application requires network communication to function. The transport layer establishes a reliable connection between the TCP with the application layer by assigning a port number of source and destination.

Network layers create data packets and add a logical address for routing from the source to the destination across the network. Data link layers create the frames and add the header information that moves across the network. The physical layer encodes and decodes the data as bits and defines the communication between the devices."

3. What is an IP datagram?

An IP datagram allows the IP to recognise the format of data. It includes the header and data which are to be transmitted. While answering this question, you can mention the usage of IP datagrams.

Example: "IP datagram combines the words data and telegram. It is a message that contains data and does not require confirmation of being received at the other end. IP datagrams are often useful for streaming devices."

4. How does IP protect data on the network?

IP security encrypts data at the application layer. It provides security to the routers that send data across the public network. It also includes authentication without encryption, like authenticating the origin of the data.

Example: "IP does not guarantee to deliver the data correctly and leaves the data protection issues to the transport protocol. TCP has a mechanism that guarantees data delivery to the right application. The IP layer can ensure that the packet's destination gets correctly identified and delivered. Using the checksum mechanism, the transport layer protocols can check whether the data delivered is correct."

5. How can we measure the performance of the IP link?

Network performance monitoring can help identify the location of the problem. It helps in determining whether there is any prevailing issue with the network. In your answer, you can briefly explain the procedure of measuring the performance of an IP link.

Example: "You can time how long it takes FTP or RCP a large file over the link. Simultaneously, it is essential to remember that the measurement can be inaccurate because of the time spent on the filesystems, rather than just the network. It is necessary to measure the time to receive the file and not the time to send it."

6. What is the difference between flow control and error control?

Flow control and error control are two primary responsibilities of a data link layer. Both the procedures differ from each other. For this question, you can state the essential differences between the flow and error control methods.

Example: "Flow control is a method that maintains proper data transmission from the sender to the receiver. Error control ensures the delivery of error-free data from the sender to the receiver. Flow control avoids overrunning and prevents data loss. In contrast, error control detects and corrects the errors which may have occurred during transmission."

7. What is a socket?

A socket programming interface offers the routines required for interprocess communication between programs on the local system or spread throughout a distributed TCP/IP-based network environment. Once a connection gets established, a socket descriptor specifically identifies a peer-to-peer connection.

Example: "A TCP/IP socket often communicates between two computers. It includes the IP address and the host that those computers use to transmit data. All the applications in the transmission use the socket to send and receive information. The primary purpose of the socket is to identify the network server's unique IP address and the port number."

8. What is the function of a router?

The router is a networking device that can forward data packets between computer networks and perform traffic-directing functions on the Internet. You can mention a few of its functions in your answer to this question.

Example: "A router is a commonly used networking device which sends and receives data on computer networks. It divides bigger networks into smaller ones. It also provides security, allowing to embed firewalls or other content filtering software to cut off unwanted websites."

9. What is the difference between OSI and TCP/IP?

OSI is a conceptual framework describing the functioning of a network. TCP/IP is a communications protocols suite which allows devices to connect over the internet. You can mention the critical differences between both concepts in your answer during the interview.

Example: "The International Standard Organisation (ISO) developed the Open Systems Interconnection (OSI) model and the Advanced Research Project Agency Network (ARPANET) TCP/IP model. OSI can provide an easy replacement of the hidden protocols, whereas TCP/IP does not. The OSI header has five bytes and seven layers, whereas the TCP/IP header has 20 bytes and four layers. OSI provides connection-oriented services at the transport layer. In contrast, TCP/IP provides connection-oriented and connectionless services at the transport layer."

10. What are the advantages of using TCP/IP?

TCP/IP has many advantages that you can focus on while answering this question. Consider the ones you found are the most crucial benefits that it offers. You may also include prior incidents where these advantages helped to overcome relevant challenges.

Example: 'TCP/IP allows heterogeneous networking without depending on the operating system for its operations. It allows networks to get added to the client-server architecture without disturbing the existing components. It provides a domain name to every website and IP address to every network and maps a domain name to the IP address.'

11. Mention some real-life applications of TCP/IP

You can use TCP/IP to deliver webpages, email, interactive data transfer and remote file system access over a network. It is also valuable for providing remote login for interactive file transfers. You can mention its application in your experience as an example to answer this question.

Example: "Browsers use TCP/IP to load webpages. Messaging platforms use the TCP/IP transport method when you see the information about the message being delivered or read. Other social platforms also make use of TCP/IP protocols for various purposes to enhance user convenience."

12. What is a common problem with TCP/IP?

TCP/IP has several problems related to routing and security. Troubleshooting methods applied effectively can resolve these issues. You can highlight a few common problems in your answer and offer solutions.

Example: "One of the common problems is TCP/IPs inability to communicate with a host on the network and routing problems. One way to resolve these issues is by implementing resolver routines on a host running TCP/IP attempt to resolve names, using the sources in an ordered list."

Tips To Prepare For TCP/IP Interview Questions

Here are some tips that can help you create a positive and long-lasting impression in your upcoming interview:

Cite examples in your answer whenever possible. You can identify the key topics and prepare your answers and examples in advance, as it can help you demonstrate your theoretical and practical understanding of the technical concepts.
Compile a list of potential interview questions. It can help you prepare, answer with confidence and improve your speech and body language, which can impress the interviewers and increase your chances of getting shortlisted.
Repeat questions out aloud. It can help you analyse the question and ensure that you understand it correctly. If it has multiple components, you can also take time to understand each part and ensure that you answer each one.