Computer Networking Questions 2021 with Answers (for Freshers/Exp)

Computer Networking Questions

In this technological world, there cannot be anyone who has never used the internet. One can easily find Computer Networking Questions 2021 with the help of internet. Earlier when a person wants to appear for an interview, needs to go through all the concerned books and materials available page by page carefully. But the internet has made it all so easy. On this page, we have listed 40+ Computer Networking Questions and Answers for freshers candidates as well as Networking interview questions for experienced.

Technical Questions On Computer Networks

There are several sets of Questions with Answers available on this page for freshers as well as experienced candidates. Hence, preparing for an interview has become very simpler these days. After going through the basics of Computer Networking Questions 2021 on this page which is well created by the team of, you will Crack Interview Round easily. Computer networks is one of the most important chapter for any candidate pursuing career in information technology field.

Computer Networking Questions Answers PDF

Computer Networking Question Bank PDF

Computer Networking Multiple Choice Questions Answers

Computer Networking Questions

Computer Networking is the interconnection of multiple devices, generally termed as Hosts connected using multiple paths for the purpose of sending/receiving data or media. Here below we are providing the list of basic questions on computer networks. Check out the best computer networks basics questions and answers and also download computer networks questions with answers pdf.

Question1: Define Network?

Answer: A network is a set of devices which in which two or more nodes are connected by a physical linked or more than two networks.

Question2: what is a Link?

Answer: A link refers to the connectivity between two devices which includes the type of cables and protocols that are used in order to communicate one device with the other.

Question3: what is Protocol?

Answer: A protocol is a set of rules that govern all aspects of information communication.

Question4: Name the factors that affect the performance of the network?


  • Number of Users
  • Type of transmission medium
  • Hardware
  • Software

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Question5: what is a LAN?

Answer: LAN is short for Local Area Network. It refers to the connection between computers and other network devices that are located within a small distance location.

Question6: Describe Network Topology?

Answer: Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

Question7: what is WAN?

Answer: WAN (Wide Area Network), is an interconnection of computers and devices that are geographically dispersed. It connects networks that are located in different regions and countries.

Question 8: Describe Network Topology?

Answer: Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.

Question9: Describe star topology?

Answer: Star topology consists of a central hub that connects to nodes. This is one of the easiest to setup and maintain.

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Question10: what are gateways?

Answer: Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is a key in allowing different systems to communicate on the network.

Question 11: what is the use of a default gateway?

Answer: Default gateways provide means for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.

Question12: what common software problems can lead to network defects?

Answer: Software related problems can be any or a combination of the following:

  • Client server problems
  • Application conflicts
  • Error in configuration
  • Protocol mismatch
  • Security issues
  • User policy and rights issues

Question13: Explain the importance of authentication?

Answer: Authentication is the process of verifying a user’s credentials before he can log into the network. It is normally performed using a username and password. This provides a secure means of limiting the access from unwanted intruders on the network.

Question 14: Explain profile in terms of networking concept?

Answer: Profiles are the configuration settings made for each user. A profile may be created that puts a user in a group, for example.

Question 15: Differentiate between hub and switch.


  • Hub is a layer 1 device while Switch is layer 2 device.
  • Hub works on single collision and single broadcast domain while switch works on per port collision and single broadcast domain.

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Question16: What is NIC?


  • NIC stands for Network Interface Card.
  • It is a peripheral card attached to a PC to helps it connect to a network.

Question17: What are the advantages of fiber optics cable?

Answer: The advantages of fiber optics cable over twisted pair cable are Noise resistance-As they use light so external noise is not a factor. Less signal attenuation-fiber optics transmission distance is significantly greater than that of other guided media. Higher bandwidth-It can support higher bandwidth.

Question18: Define IP?

Answer: Internetwork protocol (IP) is the transmission mechanism used by TCP/IP protocol. It is an unreliable and connectionless datagram protocol. It provides no error checking and tracking.

Question 19: What do you mean by redundancy?

Answer: Redundancy is the concept of sending extra bits for use in error detection. Three common redundancy methods are parity check, cyclic redundancy check (CRC), and checksum.

Question20: Define TCP?

Answer: It is connection oriented protocol. It consist byte streams originating on one machine to be delivered without error on any other machine in the network. While transmitting it fragments the stream to discrete messages and passes to interne layer. At the destination it reassembles the messages into output stream.

Question21: What are the layers of the OSI reference model?

Answer: There are 7 OSI layers: Physical Layer, Data Link Layer, Network Layer, Transport Layer, Session Layer, Presentation Layer and Application Layer.

Question 22: What is the maximum length allowed for a UTP cable?

Answer: A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

Question23: What does 10Base-T mean?

Answer: The 10 refers to the data transfer rate, in this case is 10Mbps. The word Base refers to base band, as oppose to broad band. T means twisted pair, which is the cable used for that network.

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Question24: What is the advantage of address sharing?

Answer: By using address translation instead of routing, address sharing provides an inherent security benefit. That’s because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

Question25: What is DHCP?

Answer: DHCP is short for Dynamic Host Configuration Protocol. Its main task is to automatically assign an IP address to devices across the network. It first checks for the next available address not yet taken by any device, then assigns this to a network device.

Question26: What is the difference between TFTP and FTP application layer protocols?

Answer: The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP.

The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offer by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.

Question27: Explain 5-4-3 rule?

Answer: In a Ethernet network, between any two points on the network ,there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.

Question 28: What is autonomous system?

Answer: It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.

Question29: Define Encoder?

Answer: A device or program that uses predefined algorithms to encode, or compress audio or video data for storage or transmission use. A circuit that is used to convert between digital video and analog video.

Question 30: Define Decoder?

Answer: A device or program that translates encoded data into its original format (e.g. it decodes the data). The term is often used in reference to MPEG-2 video and sound data, which must be decoded before it is output.

Question 31: What are Unicasting, Anycasting, Multiccasting and Broadcasting?

Answer: If the message is sent from a source to a single destination node, it is called Unicasting. This is typically done in networks.

If the message is sent from a source to a any of the given destination nodes. This is used a lot in Content delivery Systems where we want to get content from any server.

If the message is sent to some subset of other nodes, it is called Multicasting. Used in situation when there are multiple receivers of same data. Like video conferencing, updating something on CDN servers which have replica of same data.

If the message is sent to all the nodes in a network it is called Broadcasting. This is typically used in Local networks, for examples DHCP and ARP use broadcasting.

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Question 32: What are layers in OSI model?

Answer: There are total 7 layers

  1. Physical Layer
  2. Data Link Layer
  3. Network Layer
  4. Transport Layer
  5. Session Layer
  6. Presentation Layer
  7. Application Layer

Question 33: What is Stop-and-Wait Protocol?

Answer: In Stop and wait protocol, a sender after sending a frame waits for acknowledgement of the frame and sends the next frame only when acknowledgement of the frame has received.

Question 34: What is Piggybacking?

Answer: Piggybacking is used in bi-directional data transmission in the network layer (OSI model). The idea is to improve efficiency piggy back acknowledgement (of the received data) on the data frame (to be sent) instead of sending a separate frame.

Question 35: Differences between Hub, Switch and Router


Physical Layer DeviceData Link Layer DeviceNetwork Layer Device
Simply repeats signal to all portsDoesn’t simply repeat, but filters content by MAC or LAN addressRoutes data based on IP address
Connects devices within a single LANCan connect multiple sub-LANs within a single LANConnect multiple  LANS and WANS together.
Collision domain of all hosts connected through Hub remains one. i.e., if signal sent by any two devices can collide.Switch divides collision domain, but broadcast domain of connected devices remains same.It divides both collision and broadcast domains,

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Question 36: What happens when you type a URL in web browser?

Answer: A URL may contain request to HTML, image file or any other type.

  1. If content of the typed URL is in cache and fresh, then display the content.
  2. Else find IP address for the domain so that a TCP connection can be setup. Browser does a DNS lookup.
  3. Browser needs to know IP address for a url, so that it can setup a TCP connection.  This is why browser needs DNS service.  Browser first looks for URL-IP mapping browser cache, then in OS cache. If all caches are empty, then it makes a recursive query to the local DNS server.   The local DNS server provides the IP address.
  4. Browser sets up a TCP connection using three way handshake.
  5. Browser sends a HTTP request.
  6. Server has a web server like Apache, IIS running that handles incoming HTTP request and sends a HTTP response.
  7. Browser receives the HTTP response and renders the content.

Question 37: What is DHCP, how does it work?


  1. The idea of DHCP (Dynamic Host Configuration Protocol) is to enable devices to get IP address without any manual configuration.
  2. The device sends a broadcast message saying “I am new here”
  3. The DHCP server sees the message and responds back to the device and typically allocates an IP address. All other devices on network ignore the message of new device as they are not DHCP server.

Question 38: What is ARP, how does it work?

Answer: ARP stands for Address Resolution Protocol. ARP is used to find LAN address from Network address. A node typically has destination IP to send a packet, the nodes needs link layer address to send a frame over local link. The ARP protocol helps here.

  1. The node sends a broadcast message to all nodes saying what the MAC address of this IP address is.
  2. Node with the provided IP address replies with the MAC address.

Question 39: What is DNS?

Answer: Domain Name Server (DNS), in a non-professional language and we can call it as Internet’s phone book. All the public IP addresses and their hostnames are stored in the DNS and later it translates into a corresponding IP address.

Question 40: What is the difference between a Domain and a Workgroup?

Answer: Computers which are running on an office network or any workplace network belong to the Domain.

All computers are peers and no computer has control over another computerNetwork admin uses one or more computer as a server and provide all accesses, security permission to all other computers in a network
In a Workgroup, each computer maintains their own databaseThe domain is a form of a computer network in which computers, printers, and user accounts are registered in a central database.
Each computer has their own authentication rule for every user accountIt has centralized authentication servers which set the rule of authentication
Each computer has set of user account. If user has account on that computer then only user able to access the computerIf user has an account in a domain then user can login to any computer in a domain
Workgroup does not bind to any security permission or does not require any passwordDomain user has to provide security credentials whenever they are accessing the domain network
Computer settings need to change manually for each computer in a WorkgroupIn a domain, changes made in one computer automatically made same changes to all other computers in a network
All computers must be on same local area networkIn a domain, computers can be on a different local network
In a Workgroup, there can be only 20 computers connected

In a domain, thousands of computers can be connected

Significant Note:

You probably now have a good idea of computer networks questions and answers for freshers that can be asked in computer networks interview.

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