![Unit-3 Introduction to Computer the Networks [GU BCom 1st Sem Information Technology in Business]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrRlZtD09fnJWaG00Ljhch4RZWY85K5xG3IwH-jjZseJpo4d3Cs0KcWynYPtH3UGJbL6c0oka5dy8QOFsyIeqaJ6eK1aQ5FCfAQ3KLQBg2C6h-1yN2eRfwochSbt1RT-jmPjBitkYCKsAmdQM0rA9dCGN1WypMxlQ4GyuA82-C80pSyxBBQZ9s5TwgHD1q/s16000-rw/Information%20Technology%20in%20Business.webp "Unit-3 Introduction to Computer the Networks [GU BCom 1st Sem Information Technology in Business]")
Gauhati University BCom 1st Semester Information Technology in Business
UNIT-3
Introduction to Computer the Networks
1. The combination of two or more interconnected network is called
a) Internetwork
b) LAN
c) MAN
d) WAN
Ans: a
Explanation: Internetwork or network is formed when we connect a LAN and a WAN or two LANs to each other.
2. ISP stands for
a) International Service Provider
b) International System Provider
c) Internet Service Provider
d) Internetwork System Provider
Ans: c
3. National Internet Service Provider (ISP) networks are connected to one another by private switching network is called
a) Peering Points
b) Network Access Points
c) National ISP
d) None of thes
Ans: b
4. The network that provides high-speed connectivity of transmission speed is
a) MAN
c) WAN
b) LAN
d) Internetwork
Ans: b
Explanation: Transmission speed: LAN > MAN > WAN.
5. Which of the following network is a small, single-site network?
a) MAN
b) LAN
c) WAN
d) DSL
Ans: b
Key points:
LAN covers small site areas such as a single building or campus of up to a few km range.
MAN covers city or group of corporate offices.
WAN covers a large area such as city, state, country, or world.
6. Common LAN topologies are
a) Bus and Ring
b) Mesh and Ring
c) Star
d) both a and c
Ans: d
7. A protocol is
a) a set of rules on how communication components and DTE'S are to communicate.
b) logical communication channels used for transmission of data.
c) physical communication channels used for transmission of data.
d) None of these.
Key point: A protocol is a set of rules that govern data communications.
Ans: a
8. The method of communication in which transmission of data takes place in both directions but in one direction at a time is
a) Simplex
b) Four-wire circuit
c) Half-duplex
d) Full duplex
Ans: c
9. The method of communication in which transmission of data takes place in both directions at the same time is
a) Simple
b) Four-wire circuit
c) Half-duplex
d) Full duplex
Ans: d
10. The telephone network is a good example of
a) Half-duplex
c) Full duplex
b) Simplex
d) a and c
Ans: c
Very short questions with answer
1. Keyboard and Monitor is a good example of which mo of communication
Ans: Simplex
Key point: Simplex is a unidirectional communication.
2. Which mode of communication can be used when there no need for communication in both directions at the same tim
Ans: Half duplex
3. A set of devices connected by communication links called what?
Ans: Network
4. What is Nodes ?
Ans: A node can be a computer, printer, or any other devic that sends and/or receives data generated by other nodes on th network.
5. What is point to point connection?
Ans: A connection that provides a dedicated link between two devices is called point to point connections.
6. What is multipoint connection?
Ans: A connection in which more than two specific device share a single link is called multipoint connection.
7. What is topology?
Ans: The geometric arrangement of devices on the network called Point topology.
8. A technology in which every node has a dedicated point point link to all nodes (devices) within the network is called
Ans: Mesh
9. A topology that consists by point to point links to a central hub is called of a number of devices connecter
Ans: Star topology
Key point: In star topology, devices are not directly connected to one another.
10. A topology that consists of multiple devices connected by connectors or the main cable is called
Ans: Bus topology.
11. TCP/IP is composed of how many layers?
Ans:4 layers
12. Which is the lowest layer of the OSI model?
Ans: Physical layer.
13. Which is the top layer of OSI model?
Ans: Application layer
14. Which layer of OSI model transmits raw bits over a communication channel?
Ans: Physical
15. Which layer of OSI model divides the stream of bits received from the network layer into data frames?
Ans: Data link
Key point: Data link layer is responsible for moving frames from one node to the next.
Short questions with answers
1. What do you mean by the network?
Answer: A set of devices connected to each other over the physical medium is known as a computer network. For example, the Internet.
2. What do you mean by node?
Answer: In the computer network, the node is known as a device.
3. What do you mean by Network Topology?
Answer: A network topology is a physical structure of the network that defines how the computers or nodes will be connected to each other.
4. What is Routers?
Answer: A router is a device that sends data from source to destination over the computer network.
5. What is the OSI model?
Ans:- OSI model stands for Open System Imterconection. It's a reference model describing how different applications will communicate over the computer network.
6. Explain the Different layers of the OSI model.
Ans:- The OSI (Open Systems Interconnection) model is a conceptual framework used to understand and implement network communications between different systems. It is divided into seven distinct layers, each with specific functions and protocols. Here’s a brief overview of each layer:
1. Physical Layer (Layer 1):
- Function: Transmits raw bit streams over a physical medium.
- Examples: Cables (Ethernet, fiber optics), switches, hubs.
2. Data Link Layer (Layer 2):
- Function: Provides node-to-node data transfer and error detection/correction. It organizes bits into frames.
- Examples: MAC addresses, Ethernet, switches, bridges.
3. Network Layer (Layer 3):
- Function: Handles routing of data packets between devices across different networks. It determines the best physical path for data.
- Examples: IP addresses, routers, IPv4/IPv6.
4. Transport Layer (Layer 4):
- Function: Ensures complete data transfer. It provides error checking and data flow control. It segments and reassembles data for communication between end hosts.
- Examples: TCP, UDP.
5. Session Layer (Layer 5):
- Function: Manages and controls the connections between computers. It establishes, maintains, and terminates sessions.
- Examples: Session establishment and termination protocols, NetBIOS, RPC.
6. Presentation Layer (Layer 6):
- Function: Translates data between the application layer and the network. It handles data encryption, decryption, compression, and translation.
- Examples: SSL/TLS, encryption protocols, data formatting (JPEG, ASCII).
7. Application Layer (Layer 7):
- Function: Provides network services directly to applications. It’s the layer closest to the end user.
- Examples: HTTP, FTP, SMTP, DNS, IMAP.
Each layer serves a specific purpose and communicates with the layers directly above and below it, creating a comprehensive protocol stack that supports various network functions and services.
7. Describe Hub, Switch, and Router. Answer:
Hub: Hub will broadcast all data to every port. It has a common connection point for all devices.
Switch: The switch will create a dynamic connection and provide information to the requesting port.
Router: The router is the device responsible for forwarding data packets.
Let us move to the next Computer Network Interview Questions.
8. What do you mean by the TCP/IP Model?
Answer: TCP/IP stands for Transmission control protocol and Internet protocol. It describes how the data will get transmitted and routed from end-to-end communication.
9. Write the different Layers of the TCP/IP Model.
Answer: Application Layer, Transport Layer, Network or Internet Layer, and Network interface layer.
10. What do you mean by HTTP?
Answer: HTTP stands for Hyper Text Transfer Protocol, and the port is 80. This protocol is responsible for web content.
11. What do you mean by TCP and UDP?
Answer: TCP stands for Transfer control protocol, UDP stands for User Datagrams protocol, TCP is a connection-oriented protocol, and UDP is a Connectionless protocol.
12. What do you mean by a Firewall?
Answer: A firewall is a security system that will help computers protect them from unauthorized access or any cyber-attack.
13. What do you mean by DNS?
Answer: DNS Stands for Domain Name System. It's an internet address mapping process with the local name. We can also call it an internet phonebook.
14. What do you mean by Proxy server?
Answer: A proxy server prevents external users who are unauthorized to access the network.
15. What do you mean by NIC?
Answer: NIC stands for Network interface card. It is an adapter that will be installed on the computer, and because of that NIC, only that computer will interact with the network.
16. What do you mean by ASCII?
Answer: ASCII is the American Standard Code for Information Interchange.
17. What are the types of modes available in the network?
Answer: Data transferring mode in a computer network will be of three types: Simplex, Half-Duplex, and Full Duplex.
18. What do you mean by SLIP protocol?
Answer: SLIP stands for Serial Line Interface Protocol. Its an IP datagram over a network in a single line.
Let us move to the next Computer Network Interview Question
19. What are the key elements of the protocol?
Answer: There are three key elements of the protocol:
Syntax: Describe the format of the data. Semantics: Describe the meaning of each section.
Timings: Explain the timing of how fast the data cant sent.
20. What is the role of IEEE in the world of compute networks?
Answer: The IEEE full form is the Institute of Electrical an Electronic Engineers, which defines and develops the standards use over the network.
21. What is the maximum segment length of a 100Base-F network?
Answer: The maximum segment length will be 412 meters.
Long Questions
1. What is the network?
Ans: According to Merriam-Webster, Network is usually an informally interconnected group or association of different entities like a person, computers, radio stations, etc.
For example, Dominos has a network of 1232 branches across India. As the name suggests the computer network is a system of peripherals or computers interconnected with each other and has a standard communication channel established between them to exchange different types of information and data.
2. Why is the computer network so important?
Ans: Have you ever heard of the Internet or the NET? I guess you have, as you are already reading this article on Interviewbit.
surfing the internet. But, have you ever thought about the internet? The Internet is a network of a network connecting all different network- enabled devices which enable data and information sharing between them and that makes computer networks a core part of our life and technical interviews.
Network types can be classified and divided based on the area of distribution of the network. The below diagram would help to understand the same:
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4. Explain different types of networks.
Ans: Below are few types of networks:
Type
PAN (Personal Area Network)
LAN (Local Area Network)
MAN (Metropolitan Area Network)
WAN (Wide Area Network)
GAN (Global Area Network)
Description
Let devices connect and communicate over the range of a person. E.g. connecting Bluetooth devices.
It is a privately owned network that operates within and nearby a single building like a home, office, or factory
It connects and covers the whole city. E.g. TV Cable connection over the city
It spans a large geographical area, often a country or continent. The Internet is the largest WAN
It is also known as the Internet which connects the globe using satellites. The Internet is also called the Network of WANs.
5. Explain LAN (Local Area Network)
Ans: LANs are widely used to connect computers/laptops and consumer electronics which enables them to share resources (e.g printers, fax machines) and exchange information. When LANs are used by companies or organizations, they are called enterprise networks. There are two different types of LAN networks i.e wireless LAN (no wires involved achieved using Wi-Fi) and wired LAN (achieved using LAN cable). Wireless LANs are very popular these days for places where installing wire is difficult. The below diagrams explain both wireless and wired LAN.
LAN (Local Area Network)
5. Tell me something about VPN (Virtual Private Network)
Ans: VPN or the Virtual Private Network is a private WAN (Wide Area Network) built on the internet. It allows the creation of a secured tunnel (protected network) between different networks using the internet (public network). By using the VPN, a client can connect to the organization's network remotely. The below diagram shows an organizational WAN network over Australia created using VPN:
VPN (Virtual Private Network)
6. What are the advantages of using a VPN?
Ans: Below are few advantages of using VPN:
VPN is used to connect offices in different geographical locations remotely and is cheaper when compared to WAN connections.
VPN is used for secure transactions and confidential data transfer between multiple offices located in different geographical locations.
VPN keeps an organization's information secured against any potential threats or intrusions by using virtualization.
VPN encrypts the internet traffic and disguises the online identity.
7. What are the different types of VPN?
Ans: Few types of VPN are:
Access VPN: Access VPN is used to provide connectivity to remote mobile users and telecommuters. It serves as an alternative to dial-up connections or ISDN (Integrated Services Digital Network) connections. It is a low-cost solution and provides a wide range of connectivity.
Site-to-Site VPN: A Site-to-Site or Router-to-Router VPN is commonly used in large companies having branches in different locations to connect the network of one office to another in different locations. There are 2 sub-categories as mentioned below:
Intranet VPN: Intranet VPN is useful for connecting remote offices in different geographical locations using shared infrastructure (internet connectivity and servers) with the same accessibility policies as a private WAN (wide area network).
Extranet VPN: Extranet VPN uses shared an intranet, suppliers, customers, partners, and other entities an connects them using dedicated connections.
8. What are nodes and links?
Ans: Node: Any communicating device in a network is calle a Node. Node is the point of intersection in a network. It can send receive data and information within a network. Examples of the nod can be computers, laptops, printers, servers, modems, etc.
Link: A link or edge refers to the connectivity between twe nodes in the network. It includes the type of connectivity (wired o wireless) between the nodes and protocols used for one node to be able to communicate with the other.
9. What is the network topology?
Ans: Network topology is a physical layout of the network connecting the different nodes using the links. It depicts the connectivit between the computers, devices, cables, etc.
10. Define different types of network topology
Ans: The different types of network topology are given below Bus Topology:
All the nodes are connected using the central link known as the bus.
It is useful to connect a smaller number of devices.
If the main cable gets damaged, it will damage the whole network.
Star Topology:
All the nodes are connected to one single node known as the central node.
It is more robust.
If the central node fails the complete network is damaged.
Easy to troubleshoot.
Mainly used in home and office networks.
Ring Topology:
Each node is connected to exactly two nodes forming a ring Structure
If one of the nodes are damaged, it will damage the whole network
alt is used very rarely as it is expensive and hard to install and manage.
Mesh Topology
Each node is connected to one or many nodes.
It is robust as failure in one link only disconnects that node.
It is rarely used and installation and management are difficult.
Tree Topology:
A combination of star and bus topology also known as an extended bus topology.
All the smaller star networks are connected to a single bus.
If the main bus fails, the whole network is damaged.
Hybrid:
It is a combination of different topologies to form a new topology.
It helps to ignore the drawback of a particular topology and helps to pick the strengths from 12.
11. Describe the OSI Reference Model
Open System Interconnections (OSI) is a network architecture model based on the ISO standards. It is called the OSI model as it deals with connecting the systems that are open for communication with other systems.
The OSI model has seven layers. The principles used to arrive at the seven layers can be summarized briefly as below:
Create a new layer if a different abstraction is needed.
Each layer should have a well-defined function.
The function of each layer is chosen based on internationally standardized protocols.
12. Define the 7 different layers of the OSI Reference Model Here the 7 layers of the OSI reference model:
Ans: Layers of OSI Model
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The OSI (Open Systems Interconnection) Reference Model is a conceptual framework used to understand and implement standard protocols in networking. It divides the process of communication into seven distinct layers, each with specific functions:
1. Physical Layer:
- Concerned with the transmission and reception of raw bit streams over a physical medium.
- Deals with hardware components like cables, switches, and network interface cards.
- Responsible for data rates, physical connections, and signal transmission.
2. Data Link Layer:
- Ensures error-free transfer of data frames between two nodes on the same network.
- Handles error detection and correction, frame synchronization, and flow control.
- Divided into two sublayers: MAC (Media Access Control) and LLC (Logical Link Control).
3. Network Layer:
- Manages the routing of data packets between devices across different networks.
- Determines the best path for data to travel from source to destination.
- Uses IP addresses for routing decisions.
4. Transport Layer:
- Provides end-to-end communication control and ensures complete data transfer.
- Manages data segmentation, flow control, error detection and correction, and reassembly of data packets.
- Common protocols include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).
5. Session Layer:
- Manages sessions or connections between applications.
- Establishes, maintains, and terminates connections.
- Handles session checkpoints and recovery, ensuring continuous data exchange.
6. Presentation Layer:
- Translates data between the application layer and the network.
- Manages data encryption, decryption, compression, and translation.
- Ensures that data sent from the application layer of one system is readable by the application layer of another system.
7. Application Layer:
- Provides network services directly to end-user applications.
- Interfaces directly with software applications to provide communication functions.
- Examples of protocols include HTTP, FTP, SMTP, and DNS.
These layers work together to facilitate communication between different networked systems and ensure interoperability and standardization.
14. Describe the TCP/IP Reference Model
Ans: It is a compressed version of the OSI model with only 4 layers. It was developed by the US Department of Defence (DoD) in the 1980s. The name of this model is based on 2 standard protocols used i.e. TCP (Transmission Control Protocol) and IP (Internet protocol).
15. Define the 4 different layers of the TCP/IP Reference Model.
Ans:
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16. Differentiate OSI Reference Model with TCP/ Reference Model.
Ans:
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OSI Reference Model
7 layered architecture
Fixed boundaries and functionality for each layer
Low Reliability
Vertical Layer Approach
TCP/IP Reference Model
4 layered architecture
Flexible architecture with no strict boundaries between layers
High Reliability
Horizontal Layer Approach
17. What are the HTTP and the HTTPS protocol?
Ans: HTTP is the Hyper Text Transfer Protocol which defines the set of rules and standards on how the information can be transmitted on the World Wide Web (WWW). It helps the web browsers and web servers for communication. It is a 'stateless protocol' where each command is independent with respect to the previous command. HTTP is an application layer protocol built upon the TCP. It uses port 80 by default.
HTTPS is the HyperText Transfer Protocol Secure or Secure HTTP. It is an advanced and secured version of HTTP. On top of HTTP, SSL/TLS protocol is used to provide security. It enables secure transactions by encrypting the communication and also helps identify network servers securely. It uses port 443 by default.
18. What is the SMTP protocol?
Ans: SMTP is the Simple Mail Transfer Protocol. SMTP sets the rule for communication between servers. This set of rules helps the software to transmit emails over the internet. It supports both End-to-End and Store-and-Forward methods. It is in always-listening mode on port 25.
19. What is the DNS?
Ans: DNS is the Domain Name System. It is considered as the devices/services directory of the Internet. It is a decentralized and hierarchical naming system for devices/services connected to the Internet. It translates the domain names to their corresponding IPs. For e.g. interviewbit.com to 172.217.166.36. It uses port 53 by default.
20. What is the use of a router and how is it different from a gateway?
Ans: The router is a networking device used for connecting two or more network segments. It directs the traffic in the network. It transfers information and data like web pages, emails, images, videos, etc. from source to destination in the form of packets. It operates at the network layer. The gateways are also used to route and regulate the network traffic but, they can also send data between two dissimilar networks while a router can only send data to similar networks.
21. What is the TCP protocol?
Ans: TCP or TCP/IP is the Transmission Control Protocol/ Internet Protocol. It is a set of rules that decides how a computer connects to the Internet and how to transmit the data over the network. It creates a virtual network when more than one computer is connected to the network and uses the three ways handshake model to establish the connection which makes it more reliable.
22. What is the UDP protocol?
Ans:- The UDP (User Datagram Protocol) is a connectionless communication protocol used in computer networks. It allows the transmission of data without establishing a connection, making it faster but less reliable than TCP (Transmission Control Protocol). UDP is used in applications where speed is crucial and occasional packet loss is acceptable, such as streaming media, online gaming, and VoIP (Voice over Internet Protocol).
23. Compare between TCP and UDP
Ans: Comparison between TCP and UDP given below:
24. What is the ICMP protocol?
Ans: ICMP is the Internet Control Message Protocol. It is a network layer protocol used for error handling. It is mainly used by network devices like routers for diagnosing the network connection issues and crucial for error reporting and testing if the data is reaching the preferred destination in time. It uses port 7 by default.
25. What is the firewall?
Ans: The firewall is a network security system that is used to monitor the incoming and outgoing traffic and blocks the same based on the firewall security policies. It acts as a wall between the internet (public network) and the networking devices (a private network). It is either a hardware device, software program, or a combination of both. It adds a layer of security to the network.
26. What are Unicasting, Anycasting, Multicasting and Broadcasting?
Ans: Unicasting: If the message is sent to a single node from the source then it is known as unicasting. This is commonly used in networks to establish a new connection.
Anycasting: If the message is sent to any of the nodes from the source then it is known as anycasting. It is mainly used to get the content from any of the servers in the Content Delivery System.
Multicasting: If the message is sent to a subset of nodes from the source then it is known as multicasting. Used to send the same data to multiple receivers.
Broadcasting: If the message is sent to all the nodes in a network from a source then it is known as broadcasting. DHCP and ARP in the local network use broadcasting.
27. What happens when you enter google.com in the web browser?
Ans: Below are the steps that are being followed: Check the browser cache first if the content is fresh and present in cache display the same.
If not, the browser checks if the IP of the URL is present in the cache (browser and OS) if not then request the OS to do a DNS lookup using UDP to get the corresponding IP address of the URL from the DNS server to establish a new TCP connection.
A new TCP connection is set between the browser and the server using three-way handshaking.
An HTTP request is sent to the server using the TCP connection.
The web servers running on the Servers handle the incoming HTTP request and send the HTTP response.
The browser process the HTTP response sent by the server and may close the TCP connection or reuse the same for future requests.:
If the response data is cacheable then browsers cache the same. Browser decodes the response and renders the content.
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