Computer Networks Interview Questions You'llMost Likely Be Asked

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Computer Networks Interview Questions You'll Most Likely Be Asked is a perfect companion to stand ahead above the rest in today’s competitive job market. Rather than going through comprehensive, textbook-sized reference guides, this book includes only the information required immediately for job search to build an IT career. 

This book puts the interviewee in the driver's seat and helps them steer their way to impress the interviewer. 


Table of Contents

1. Wireless Networks
2. Ethernet
3. Protocols
4. Transmission Medium
5. General
6. Routing Algorithms
7. HR Questions


a) 200 Computer Networks Interview Questions, Answers and Proven Strategies for getting hired as an IT professional 
b) Dozens of examples to respond to interview questions 
c) 51 HR Questions with Answers and Proven strategies to give specific, impressive, answers that help nail the interviews 
d) 2 Aptitude Tests download available on


Sample from the book

(Below Questions and Answers are randomly taken from different pages of the book)

84: What is a subnet?


A communication subnet or a subnet is a collection of transmission links such as copper wire, fiber optics or radio link and switching elements known as routers which are used to connect various host machines owned by customers. A subnet is usually owned by a telephone company or an Internet Service Provide (ISP) and is responsible for carrying messages from one host machine to another.


85: What is the difference between internet and Internet?


internet: The term is used in generic sense and usually used to refer to a group of interconnected different networks; internet is also known as inter-network. An example of internet is a group of LANs connected by a WAN.

Internet: The term “Internet” is used to refer to World Wide Web where a user can browse for information, communicate with others using emails, read online news papers, and shop online.


86: What is the difference between connection oriented and connectionless service?


In a connection-oriented service, when messages have to be sent from a source machine to a destination machine, the source machine establishes connection with the destination machine, transmits the messages to the destination machine and when the transmission of messages is over, the connection is terminated by the source machine. Parameters such as size of the message, quality of service etc are decided by source machine, destination machine and the carrier (subnet).

In connectionless service, when a message has to be sent from source machine to destination machine, a physical connection is not made; instead the source machine writes the address of the destination in the message and sends the message over the network. The message passes through multiple intermediate machines and finally reaches the destination.


87: What is the difference between OSI and TCP/IP reference model?


Open Systems Interconnection (OSI) reference model:

a) It has seven layers: physical layer, data link layer, network layer, transport layer session layer, presentation layer and application layer.

b) It takes guarantee of reliable delivery of packets at the transport layer.

c) Protocols were introduced after the model was devised.

Transmission Control Protocol/ Internet Protocol (TCP/IP) model:

a) It has four layers: host-to- host layer, internet layer, transport layer and application layer.

b) It does not take guarantee of reliable delivery of the packets at the transport layer.

c) Protocols were devised before the model was devised.


88: What is the responsibility of physical layer?


The responsibility of physical layer is to transmit binary digits over the transmission medium. The layer is responsible for ensuring that if data bits such as 100101 are sent, then at the receiving side, these data bits are received as it is i.e.100101. The layer deals with issues such as how many volts are needed to represent either 0 or 1. For example, should a 1 be represented by +5V or +10 V, should the data be transmitted in single direction or both the directions, what should be the transmission time of a digit, how a connection should be established and how a connection should be disconnected.


89: What is the responsibility of data link layer?


The main responsibility of data link layer is to transfer error free data from source machine to destination machine. It breaks the incoming data into small units called frames and sends the frames sequentially to the destination. This layer deals with two main issues:

a) Flow control: This layer implements a flow control scheme which informs the sender about the buffer space of the receiver so that the sender can adjust the rate at which it is sending data to the receiver.

b) Error control: This layer calculates checksum i.e. number of bits present in a frame, adds the checksum to each outgoing frame and re-computes the checksum at the receiver side to ensure that transferred data is error free.


90: What is the responsibility of network layer?


Network layer determines how a packet (a unit of data) is routed from source to destination. A route can either be static or dynamic. In static routing, a table containing multiple routes is wired into the network. In dynamic routing, a route is determined at the beginning of a connection.

Network layer handles issues such as network congestion, quality of service i.e. delay, transmit time etc. When packets are transmitted between two heterogeneous networks that use different address formats then the network layer is responsible for converting one address format to another address format. If the packet size of two heterogeneous networks is different then the packet may be discarded by the layer because it may be too large or short for another type of network.