11th Class IT Notes – Computer Network (in English)

Computer Network

Q:-     Explain the purpose of Networking?         Or        What is Computer Networking?

Ans:-   Networking is widely used for sharing of resources and information & for communication purposes. Networks can also help in reducing costs. For ex. We can buy a single printer and share it across multiple users.

Two or more computers or processors are linked together with data communication devices and transmission media referred to as a computer network.

Q:-       Which are the components of network?

Ans:-   1.         Media 2.         Processor                   3.         Software         4.         Channels        5.   Topology  6.            Architecture

Q:-       Advantages of Computer Network

Ans:-   Sharing, sharing resources, backups , communication, reduction in the cost

Q:-       Disadvantage of computer network

Ans:-   Crash, Data Insecurity, No Privacy

Q:-       What is LAN?

Ans:-   LAN(Local Area Network) – when two or more computers are connected in a small area such a network is known as local area network. For ex. Schools, colleges, offices, etc.

Q:-       What is WAN(Wide Area Network)?

Ans:-   A Wide Area Network is connection of two or more computers which are geographically area.

For ex. Computers in branch could connect to the computer networks at head office by telephone lines or satellites.

Q:-       Difference between Peer-to-Peer and Server/Client ?

Ans:-   Peer-to-Peer networks :- in P2P networks, all the devices have same status in the network and share the link equally. In such networks there is no master or controller or server.

Client-Server Networks :- These are large networks with 10 to hundreds of computers and may have dedicated servers and devices. Networks is a combination of client-server models and peer to peer.

Servers are referred to as Service Providers and Clients are referred to Service Requestors.

Q:-       Explain any three methods for connecting two or more computers.

Ans:-   There are several ways to connecting computers –

  • Use a cross-over cable
  • Use serial and parallel ports
  • Use Bluetooth
  • Use wi-fi
  • Use Hub or Network Switch

Q:-       Explain Internet, Intranet & Extranet.

Ans:-   Internet :- Internet is a global system of interconnected computer networks. It is also referred to as network of networks.  It is the largest terms of number of connected devices.

Intranet :-It is a private network to an organization. It is small network with minimal number of connected devices. It is owned by single organization. Intranets can be simple within a building or very large spread across area.

Extra-net :- Extra-net is a computer network used outside the Intranet. It is private network that used public network to share information with suppliers and vendors. The number of devices connected with intranet. Extra-net are usually accessed using VPNs.

Q:-       What is OSI Model (Open System Interconnect)

Ans:-   OSI model was developed by the International Standards Organization in 1977. OSI model is not a protocol but it is a model for understanding and designing the network architecture that is flexible robust and interoperable.

Q:-       How many layers of OSI reference Model? And Explain it?

Ans:-   There are seven layers in OSI reference model.

  1. Physical Layer Data link layer       3. Network Layer       4. Transport Layer                
  2. Session Layer 6. Presentation Layer           7. Application Layer

Physical Layer :-Physical Layer is the bottom(First) layer in the OSI model and deals with media, signal and binary transmission. It also deals with mechanical, electrical and functional characteristics of transmission media.

Data Link layer :-Data Link Layer is the second layer in the OSI model. This layer is responsible for  transfer of data over channel. Devices that operate at this layer include Network Interface Card, Bridges and Switches.

Network Layer :- Network Layer is the 3rd layer in the OSI model. It is responsible for source to destination delivery of a packet over multiple networks. Unit of measurement in network layer is packets or data gram.

Transport Layer :- Transport Layer is the 4th layer in the OSI model. It is responsible for the source to destination delivery of entire message. The unit of measurement in transport layer is Segments.

Session Layer :-  Session layer is the 5th layer in the OSI model. It is responsible for establishing between network applications.  It creates the session, manages the packets sent back and forth during the session and terminates the session.

Presentation Layer :- It is also referred to as Layer 6. The layer consists of many table of syntax and its functions are limited. The relationship of presentation layer with session and application layer. It’s functions are data presentation, data encryption and data compression.

Application Layer:- Application layer is the last layer in the OSI Model. In this layer, protocols are responsible for process to process communication across an IP network. Protocol in this layer include HTTP, FTP, SMTP, POP3, DHCP etc. Application Layers ‘s function is transfer of file, Remote login, Password Checking, Email delivery etc.

Q:-       Difference between baseband and broadband?

Ans:-   Baseband:-     Data is sent as digital signals by using entire bandwidth of the single channel. Baseband uses TDM(Time Division Multiplexing) to send multiple signals over a single cable.

Broadband:-   Data is sent as analog signals by using portion of a bandwidth. Signals are split into channels by using FDM (Frequency Division Multiplexing).

Q:-       Explain TDM and FDM.

Ans:-   TDM (time Division Multiplexing) is a method in which multiple signals are combined and send over a single transmission media such as wires or radio waves.

FDM :- FDM (Frequency Division Multiplexing) is a method in which multiple signals are transmitted at different frequencies.

Q:-       Which are the techniques to data transferred over a network?

Ans:-   Data can be transferred over a network using the following techniques

Circuit Switching :-   In this method, a dedicated path is established between the endpoints before the data is transferred. A type of communications in which a dedicated channel (or circuit) is established for the duration of a transmission. Circuit Switching is the most powerful technique used for build communication network.
It is used for ordinary telephone calls. It allows to be shared users for communications equipment and circuits.

Packet Switching :-   In this method, data is divided into blocks referred to as packets. Packet switching is a technique of grouping data transmitted over digital network into packets. Packet switching is similar to message switching. Multiple packets can be send via different paths allowing more than two devices to communicate at the same time.

Q:-       What is the channel operation and how many divided into channel operation?

Ans:-   Channel operation refers to the mode of communication between connected devices or computers. Channel operation can be simplex, half-duplex or full duplex.

Simplex :– Simplex is a one way communication. In these system the information is communicated in only one direction. For example, Radio or TV broadcasting system can only transmit but cannot receive.

Half Duplex:- Half Duplex is a two way communication but only one way at a time. These systems can either transmit or receive, for example a trans-receiver or walky-talky set.

Full Duplex :- Full duplex is two way simultaneous communication received. These are truly bi-directional systems. These systems can transmit as well as receive simultaneously. Example – telephone systems.

Q:-       Explain Network Topology?

Ans:-   A network topology is the arrangement of a network, including its nodes and connecting lines. There are two ways of defining network geometry : the physical topology and the logical topology.

Q:-       What are the types of Network Topology?

Ans:-   There are different types of Network Topology –

Bus Topology :- In Bus topology, Every computer and network device is connected to single cable. In Bus topology the nodes are interconnected using co-axial cables through the T-connector.A bus network is a network topology in which nodes are directly connected to a common linear (or branched) half-duplex link called a bus.

Star Topology :- Star topology is the most common and widely used topology today. Each computer is connected to a centralized device called the hub or switch. Star topology gives performance better than as compared to bus topology.

Ring Topology:-A ring topology the various nodes are connected in form of a ring or circle in which data flows of a circle from one station to another station. Devices used in ring topology include the Token Ring Network Interface Card.

Mesh Topology :- In a mesh topology, all nodes are connected to each other node in the network.

Hybrid Topology :- A hybrid Topology is a topology that combines two or more different physical topologies in a single network.

Q:-       Explain the purpose of NIC(network interface card)

Ans:-   Network cards are devices that connect computers to the network. Network cards are both physical and data link devices. It is also referred to as Ethernet Card and Network adapter. Network interface cards are available for laptop, desktop & server computers.

Q:-       What is MAC Address?

Ans:-   Mac address is also known as physical address. MAC addresses are unique to each network interface card.

Q:-       Define Network Hardware.

Ans:-   Network Hardware is the physical components needed to perform data processing and communication within the network.

Q:-       Explain the terms of HUB, Switch, Bridge.

Ans:-   HUB:- A hub is a device that connects multiple computers using a twisted pair cable. Hubs operate at OSI model Physical Layer. There are three types of hubs –

  • Passive hub
  • Active hub                                         
  • Intelligent hub

Switch :- Switch is a device that allows multiple computers to be connected using twisted pair cable. It works an the layer 2 of OSI reference model. Hub uses the half duplex communication and network in switches uses the full duplex communication mode. Switches is performance better than the hub

Bridge :– A network bridge is a computer networking device that creates a single network from multiple communication networks. This function is called network bridging. The best example of a bridge in current use is between a broadband token and base band token network.

Router :- Routers are devices that connect two or more networks. It consists of a combination of hardware and software. A router is networking device that forwards data packets between computer networks.

Q:-       Define Protocol .

Ans:-   A protocol is a set of rules and guidelines for communication data. In a computer network, all computers need to use the same protocol for communication.

Q:-       TCP/IP and IP(Internet Protocol).

Ans:-   TCP/IP :- TCP/IP protocol suit is the most widely used protocol today including LAN’s and WAN’s. Internet uses TCP/IP as its protocol.

Internet Protocol is primary communication protocol  used for transfer data across network boundaries.

Q:-          What is Terminal Services?

Ans:-     Terminal service is a component of Windows Server Operating System that makes applications installed  on the server accessible to computers in a network.

Q:-          Difference between Domains and Workgroup?

Ans:-     Domains refers to a centralized model where a centralized database stores all the credentials.

Work-group or Peer to Peer computer network refers to decentralized model where the username and password is stored on individual computers. Work-group model is suitable for 10-15 computers.

Q:           Explain Thin Clients .

Ans:-     Thin clients refers to computing devices that have minimum processing and storage capabilities. Thin clients are not expensive and help organizations reduce cost.

Q:           What is Active Directory?

Ans:-     Active Directory is a directory service used in Microsoft Windows Domain networks. Active Directory enforces security policies such as password length,  password complexity, user restriction etc.

Q:–        What is Wireless Networking?

Ans:-     Wireless network refers to a computer network that is not connected by any cables. Wireless networking is used where wired connectivity is not possible.

Wireless networks are computer networks that are not connected by cables. The use of wireless network avoid the costly process of introducing cables into buildings or as a connection between different equipment locations.

Q:-          What are the types of Wireless networking?

Ans:-     Wireless Personal Area Network(WPANs) interconnect devices within a relatively small area. For example – Bluetooth to connect to mobile phone to a laptop.

                Wireless metropolitan area network(WMANs) is wireless network that connects several wireless LANs. WiMAX is a type of wireless MAN.

                Wireless wide Area Network(WWANs) is wireless network that covers large areas, such as one between neighboring towns and cities.

Q:-          Full form of these terms:-

  • WNIC WAP                                      WPA

Ans:-     WNIC – Wireless network interface controller

                WAP –     Wireless Access Points

                SOHO – Small Office Home Office

IBSS –  Independent basic service set

WPA – Wi-Fi Protected Access

Q:-          Explain the terms of Wireless LAN and ADHOC

Ans:-     WLAN refers to connectivity between two or more devices within short distances such as homes or campus.

                ADHOC –  A ad-hoc wireless network is a decentralized type of wireless network. It is also known as peer to peer network. ADHOC mode allows wireless devices to directly communicate with each other.

Q:-          What is Wireless Security?

Ans:-     Wireless Security is the prevent of unauthorized access of damage to computers using wireless networks. Today, Every laptop and smartphone is equipped with wireless cards.

Q:-          What is Piggybacking?

Ans:-     Piggybacking refers to the practice of using wireless internet connection subscribed by others.

Q:-          Explain the terms of WEP.

Ans:-     WEP :-   WEP is a widely used security algorithm and is often the first security choice. WEP uses 64 bit or 128 bit encryption. WEP used two methods of authentication : Open System authentication and Shared Key authentication.

Q:-      Explain the purpose of Server or Network Operating Systems.

Ans:-  Server Operating System are system software that run on a server and enable the server to manage data, users, groups, security, applications, and other networking functions. Server operating system use the client/server architecture. Popular network operating system are Microsoft Windows Server 2003, Windows server 2008, UNIX.

Q:-      Explain any five functions of a Server operating System?

Ans:-  Server Operating System include a various types of functions –

1.     Name Server 2.     Mail Server
3.     File server 4.     Print server
5.     Web server 6.     Gaming server
7.     Remote access server 8.     Communication server

Q:-      Explain the term of Unix and Linux.

Ans:-  UNIX :- UNIX is a multitasking, multi-user computer operating system. UNIX operating system is widely used in servers, workstations and mobile devices.

Linux :-  Linux is a like Unix operating system under the model of free and open source software development and distribution.

Q:-      List any five variants of UNIX.

Ans:-  SUN Solaris,  IBM AIX,  BSD OS,  HP-UX, Digital Unix, MAC OS X Server

Q:-      List any five distributions of Linux.

Ans:-  Debian,   REdhat,   Android,   Ubuntu,  Fedora.

Q:-      What is UDP and TCP?

Ans:-  UDP ( User Datagram Protocol) :-  UDP is a transport layer protocol that is used for sending messages to other hosts on the network without communications.

            TCP (Transmission Control Protocol) :-   TCP provides reliable, delivery of bytes from a program on one computer to another program on a different computer on the network. TCP is the protocol used by major internet applications such as the World Wide Web, email, file transfer.

Q:-      Explain the PING Utility.

Ans:-  PING is a command line utility used for testing network connectivity.  PING is widely used by administrators to understand.

Q:-       Explain the purpose of DHCP.

Ans:-    Dynamic Host Configuration Protocol(DHCP) is a network protocol. It is used to configure network devices to communicate on an IP network. DHCP is widely used in enterprise networks.

DHCP consists of two types –

DHCP Servers

DHCP Clients

DHCP server maintains database of IP address and configuration information.  When  it receives a request from a client, the DHCP server allocates an IP address and sends the information to the clients.


Q:-       Full form of these terms –

  • TCP/IP (ii) DNS     (iii)       WINS               (iv) DDNS (v)   TLD    (vi)    ICANN      (vii)      IANA                (viii)     DHCP


TCP/IP – Transmission Control Protocol DNS     –           Domain Name Server
WINS   –   Windows Internet Name Service DDNS   –           Dynamic DNS
TLD      –   Top Level Domains ICANN –           Internet Corporation for assigned Names and Numbers
IANA    –    Internet Assigned Numbers Authority

Q:-       What is Host Name?

Ans:-    Hostname is a command line utility that can retrieve computer name.

Q:-       What is NSLookup?

Ans:-    NSLookup is a command line utility used for querying DNS servers.

Q:-       Explain the Hosts File.

Ans:-    The hosts file is computer file used by the operating system to map host name to IP address. The host file is a plain text file. Host name contain maximum 255 characters. Multiple host names can be assigned to single host.

Q:-.        What is WAN(Wide area Network)?

Ans:-     A wide area network is a network that covers a broad area using private or public network. Using WANs, data canbe transmitted over very long distances.

Q:-          Explain the purpose of Dial up Connections,

Ans:-     A dial up connection is a form of network connectivity using telephone networks. Dial up connection were used to connect to the ISP for internet connectivity.  In this, computers are connected over telephone networks using a device called the MODEM.

Q:-          What is RRAS?

Ans:-     RRAS (Routing & Remote Access Server) is a feature that is used for managing remote connections. RRAS supports a variety of connections including Dial-up & VPN(Virtual Private network).

Q:-          Explain the terms – ISDN , DSL, WiMax

Ans:-     ISDN(Integrated Services Digital Network) :- ISDN is a circuit network that enables digital transmission over telephone lines. ISDN is widely used for high speed internet access in most countries.

DSL (Digital Subscribe Line) – DSL is a family of technologies that provide internet access by transmitting digital data over telephone network.

WiMax :– WiMax for Microwave Access is a wireless communication standard used for providing Internet Access to fixed stations. WiMax is used where wired Internet access such as DSL or Cable is not possible.

Q:-          Difference between Proxy Server and ICS.

Ans:-     Proxy Server:- A proxy server is an application that acts as an intermediate between internal and external networks for processing request. Proxy servers hide internal networks and provide an additional layer of security. They are used to share internet connections across multiple computers.

ICS (Internet Connection Sharing) :- Internet Connection Sharing is a feature in windows Operating System that enables us to share Internet access with Other computers on a network. ICS has a built in DHCP service that automatically allocated IP address.