Class 12 IP 065 Chapter 9 Introduction to Computer Networks Assignments Sumita Arora Solution

15. How is a LAN different from a PAN?

Answer :

• LAN stands for Local Area Network while PAN stands for Personal Area Network.
• LAN are computer networks that are confined to a localized area( eg. Office or a building) while PAN are confined within the range of an individual person.
• LAN need cable like Ethernet while PAN is wireless.
• LAN have high speed while PAN have low speed.

16. How is a LAN different from a WAN?

Answer :

• LAN stands for Local Area Network while WAN stands for Wide Area Network.
• LAN is spread over a small area while WAN is spread over a very large area.
• LAN usually costs less to set it up while WAN costs higher to set it up.
• LAN is usually a single network while WAN is usually a network of many networks.

17. Can you term a PAN as a LAN? Why/Why not?

Answer : No, we cannot term a PAN as a LAN. This is because LAN is spread over a small localized area and is a single network within the range of 100-1000 m whereas PAN is the interconnection of technology devices within the range of an individual person, within a range of 10-50 m.

18. Compare Mesh with Tree topology.

Answer : Tree topology: In this topology, the network is shaped as an inverted tree with the central root branching and sub-branching to the extremities of the network. Transmission in this topology takes place in the same way as in bus topology.
Mesh topology: In this topology, each node is connected to more than one node to provide an alternative route in the case the host is either down or too busy. It is an extension to P-P network. The mesh technology is excellent for long distance transmission.

19. Compare Tree and Star topology.

Answer : Tree topology: In this topology, the network is shaped as an inverted tree with the central root branching and sub-branching to the extremities of the network. Transmission in this topology takes place in the same way as in bus topology.
Star topology: In this topology each workstation is directly linked to a central node. Devices can be easily plugged or unplugged to the central node. Any communication between the stations must pass through the central node.

20. Write two advantages and two dis-advantages for STAR topology.

Answer : Two advantages of star topology:
• Ease of service. Star topology provides easy access for service or reconfiguration of the network.
• Centralized control/ Problem diagnosis. The fact that the central node is connected directly to every other node in the network means that faults are easily detected and isolated.
Two disadvantages of star topology:
• Long cable length. Because each node is directly connected to the center, the star topology necessitates a large quantity of cable.
• Central node dependency. If the central node in a star network fails, the entire network is rendered inoperable.

21. (a) Write advantages and disadvantages of bus topology.

Answer : Advantages of bus topology:
• Short cable length and simple wiring layout
• There is a single cable through which all data propagates and to which all nodes are connected.
• Easy to extend
Disadvantages of bus topology:
• Fault diagnosis and fault isolation is difficult.
• Nodes must be intelligent.

21. (b) Write advantages and disadvantages of tree topology.

Answer : Advantages of tree topology:
• Uses point-to-point wiring for individual segments.
• It is supported by several hardware and software venders.
Disadvantages of tree topology:
• Overall length of each segment is limited by the type of cabling used.
• If the backbone line breaks, the entire segment goes down.
• It is more difficult to configure and wire than other topologies.

21. (c) Write advantages and disadvantages of mesh topology.

Answer : Advantages of mesh topology:
• Each connection can carry its own data load.
• It is robust and provides security and privacy.
• Fault diagnosis is easy.
Disadvantages of mesh topology:
• Its installation and configuration is difficult.
• Cabling cost is more.
• Bulk wiring is required for mesh topology.

22. Write the functions of the following pieces of network hardware: (i) Modem (ii) Switch

Answer : (i) Modem

Modem converts digital signals to Audio frequency tones which are in the frequency range that the telephone lines can transmit and also it can convert transmitted tones back to digital information .

Answer : (ii) Switch

Switch is responsible for filtering i.e. transforming data in a specific way and for forwarding packets between LAN segments.