Fbise Notes-Computer | Computer Networks Long Questions

Long Question Answers Long Questions Chapter No.4

i.                       What are the advantages of using networks?

    

  Ans:    Advantages of using networks:

                       The following are some common uses of networks.

             Hardware Sharing:

Network allows sharing of computer hardware such as hard disk and printer. A hard disk can be attached to a server to share it with other network users. A single hard disk can provide storage space to many users. Every user on a network can use a printer for printing documents and there is no need to buy a printer for every user. 

           Software Sharing:

Application software can be installed on a server and shared over the network. There is no need to install it on all the computers in network.

File Sharing:

            A user can easily share files with other users over the network. A user place a file in shared location on one computer and make it available to other users.

Internet Sharing:

            A single high speed internet connection can be shared with all the users over a network. There is no need to provide a separate internet connection to every user on the network.

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ii.                  Describe Client/Server and Peer-to-Peer networks.

     
      Ans: Client/Server Network:

  Server Computer:

                                    A server is the main computer in a network which is used to manage network  resources and facilitates other computers.

            
                Client Computer:

                                    Clients are computers in a network that access services made available by a server.

In a client /server network, each computer on the network acts as either server or client. Servers are not used as client computers and client computers are not used as servers. In this environment server shares its resources such as hard disk, printer and internet connection with client computers.

Characteristics of Client/Server Networks:

i.                    Client/Server network can be as small as two computers and it can have hundreds and even thousands of computers as well.

ii.                  It provides centralized security to ensure that resources are not accessed by unauthorized users.

iii.                In a network , a network administrator is responsible for sharing resources, creating user accounts and assigning privileges to all users.

Peer-to-Peer Network:

In peer-to-peer network all computers have the same status. Every computer is capable of playing the role of client, server or both at the same time. Each computer on the network is known as peer. A peer on the network can share as well as access available resource on the network.

Characteristics of Peer-to-Peer Networks:

     

1.      In a peer-to-peer network, each computer can play the role of server, client or both at the same time.

2.      These networks are suitable for a small number of users, ranging between

3.      two to ten computers. Large networks become difficult to manage.

3.      It does not provide centralized security. No single person is assigned to administer the resources of network. Individual users have complete control over resources of their computers.                  

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iii.   Describe the types of networks based on area covered.

Ans:  Types of Networks based on Geographical Area:

                                     Based on the geographical distance covered, computer networks are classified into Local Area Network, Wide Area Network and Metropolitan Area Network.

Local Area Network:

                  LAN is commonly used network. It is a network that covers a limited area, usually ranging from a small office to a campus of nearby buildings.

      Examples:

                  LAN include networks within  a school, college, business and organization.

     

      Characteristics of LAN:

i)                    LAN is restricted to a limited geographical area.

ii)                  Data Transmission speed is fast.

iii)                Data communication problems rarely occur.

iv)                 Transmission Medium is owned by the user organization.  

Wide Area Network:

                  WAN spans a large area, connecting several locations of an organization across cities, countries and continents. A WAN is often made up of two or more LANs or MANs.

      Examples:

                  WAN are the networks used in banks, airlines and national database authorities like NADRA in Pakistan. Internet is another good example of WAN.

     

      Characteristics of WAN:

i)                    WAN spans large geographical area. It can connect computers b/w cities & countries.

ii)                  Data Transmission speed is slow.

iii)                Data communication problems often occur.

iv)                 Transmission Medium is leased line or public systems like telephone lines or satellite links.

    Metropolitan Area Network:

                  A  MAN falls b/w LAN and WAN. It spans area larger than a LAN and smaller than a                    WAN.

      Examples:

                  WAN includes networks used by telecommunication companies for providing cable TV and internet services.

     

      Characteristics of MAN:

i)                    MAN can connect computers within several blocks of building to entire city.

ii)                  Data Transmission speed is slower than LAN but faster than WAN.

iii)                Fiber optic cable or wireless microwave transmission is used as communication medium.

Personal Area Network (PAN):

            A personal area network is computer network organized around an individual person. Personal area networks typically involve a mobile computer, a cell phone or hand held device like PDA. User can transfer files including e-mails, calendar appointments, photos and audio/video files. PAN can be wired or wireless. USB and FireWire technologies are used for wired and Bluetooth for wireless PAN.

Bluetooth Network:

            The process of setting up a Bluetooth network is called “pairing”. It is done through interaction b/w two users. The user interaction is required to confirm identity of the devices. When pairing completes, the two devices can communicate with each other. One device can be paired to multiple devices.

Characteristics of Bluetooth Communication:

i)                    It eliminates the need of cable to form a network.

ii)                  Transmission is secure, reliable and fast.

iii)                It creates PAN b/w devices close to each other.

iv)                It can transmit text, images and audio/video files.    

Internet (International Network):

            It is the largest computer network that connects millions of computers all over the world. Computers are connected using telephone lines, fiber optics or wireless signals. Each computer on the network uses IP (internet protocol) address. The IP identifies the location on internet.

Internet has brought a huge revolution in our daily life. It allows people to send e-mail, chat with each other and obtain information on any topic. Computer users can pay bills, do shopping, find jobs, work at home and do reservation for trains, flights and hotels through internet.                       

WWW (world wide web ) is the system use to access the Internet. It is a collection of websites on internet. To access a website user use URL, like www.fbise.edu.pk.

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iv.                Explain the types of network topologies.

             

Ans:           Network Topology:

                               the physical arrangement of network nodes is called network topology. A node represents a computer or a network device.

                 Types of Network Topologies:

                              Four types of topologies are commonly used which are bus, ring, star and mesh topology.

             
                   Bus Topology:

                              It is the simplest network topology. It consists of a single central cable known as bus. All the devices are connected to the bus along its length to communicate with each other. A computer sends a message on the bus. The computer to whom the message is sent receives it while the others ignore. At the end of bus a terminator is attached so that the signals do not bounce back on the bus causing errors.

              
            Advantages of Bus Topology:

            

            1.    It has low cast

            2.    Easy to add new computers.

            3.    Suitable for small networks.

                  Limitations of Bus Topology:

                 

                   1.   If bus is damaged at any point, the entire network stops working.

                   2.      Difficult to detect and fix faults.

Ring Topology:

                  The ring network topology is shaped just like a ring. It is like bus with both ends connected together. Messages from one node are sent to the next node. It is received by it if it is addressed otherwise it is ignored and passed on to the next until the destination is reached.

        
             Advantages of Ring Topology:

            

            1.    High network performance.

            2.    Server or switch is not required to manage the network.

            3.    All the computers have equal opportunity to transmit data.

   
             Limitations of Ring Topology:

                       

                         1.     If ring is broken at any point, the entire network stops working.

                         2.     Difficult to detect and fix faults.

                         3.     Expensive than star and bus.                  

          Star Topology:

                        In star topology all the nodes are connected to a central device called switch or hub. It is one of the commonly used network topologies. A switch can connect 4, 8, 16 or 32 nodes. A switch can be connected to another switch to expand the network.

          
              Advantages of Star Topology:

         

                1.    Provides fast communication between computers.

                2.    Easy to add new computers.

                3.    Easy to detect and fix faults.

                4.    Failure of one computer does not affect other network.

                        Limitations of Star Topology:

                       

                         1.      At least one switch/hub is required for connecting two computers.

                         2.      Lengthy cable is required to connect all computers.

                         3.      Costly to implement.

Mesh Topology:

        In mesh, all the network nodes are connected to all the other nodes. Message sent on a mesh network can take any possible path from source to destination. It is not commonly used since it is costly and difficult to implement.

                        Advantages of Mesh Topology:

            

                1.    It is most reliable network topology.

                2.    Alternative paths are available in case a path is broken.

                        Limitations of Mesh Topology:

                       

                         1.     Most expensive to implement.

                         2.     Difficult to implement.

                         3.     Difficult to add new computers.

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  v.   Write a note on Dial-up and DSL Internet connection.

Ans:        Dial-up Line:

                        Dial-up line uses standard telephone lines for internet connection. It requires a Dial-up modem that provides a maximum internet connection speed  of 56kbps.the main advantages of this connection is that it uses complex network of telephone lines that allows data to be transmitted for almost any location. It is becoming outdated due to its very slow speed.

           
               DSL:

                        DSL stands for digital subscriber line. It provides a very high speed broadband internet connection.  It is called broadband because it has broad range of frequencies for transmitting digital data.

          
            Broadband:

                        Any type of internet speed that is 256kbps or above is known as broadband. A DSL modem is required for setting up the DSL internet connection. Internet service providers have several DSL speeds available with different monthly rates.

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