6. Compare and contrast:- (i) Star and Bus topologies (ii) Star and Tree topologies (iii) Bus and Ring topologies
Answer: (i) Star and Bus topologies
i) 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.
Bus topology: This topology consists of a single length of the transmission medium onto which the various nodes are attached. The transmission from any station travels the length of the bus in both directions, and can be received by all other stations.
Answer: (ii) Star and Tree topologies
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.
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. Transimission in this topology takes place in the same way as in bus topology.
Answer: (iii) Bus and Ring topologies
Bus topology: This topology consists of a single length of the transmission medium onto which the various nodes are attached. The transmission from any station travels the length of the bus in both directions, and can be received by all other stations.
Ring topology: in this topology, each node is connected to two and only two neighboring nodes. Data is accepted from one of the neighboring nodes and is transmitted onwards to another. Data travels in one direction only, from node to node around the ring.
7. What is the role of modem in electronic communication?
Answer: A modem is a computer peripheral that connects a workstation to the other workstations via telephone lines and facilitates communications. It is short form for modulation/demodulation.
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.
8. What are hubs? What are its types?
Answer: Hubs are networking devices having multiple ports that are used for connecting multiple computers together.
Types of hubs are:
• Active Hubs
• Passive Hubs
9. What is the role of a switch in a network?
Answer: Switch is responsible for filtering i.e. transforming data in a specific way and for forwarding packets between LAN segments.
10. Briefly discuss the role of following devices in the context of networking. (i) Repeater (ii) router (iii) bridge (iv) gateway
Answer : i) Repeater: It is a device that regenerates a signal being transmitted in the network. It is used for long distance transmission.
ii) Router: A device that work like a bridge but can handle different protocols, is known as router. The router is used for forwarding data from one network to a different network.
iii) Bridge: It is a device used to link two networks together.
iv) Gateway: It is a device that connects dissimilar network.
11. What is the importance of router?
Answer : Router can work like a bridge and can also handle different protocols. It can locate te destination required by sending the traffic to another router, if the destination is unknown to itself.
12. What is gateway? What does it do?
Answer : A gateway is a networking device that connects dissimilar networks. It establishes an intelligent connection between a local network and external networks with completely different structures.
13. How is a repeater different from an amplifier?
Answer : (i) Repeater is a network device that collects the inbound signal and retransmits it, while amplifier amplifies all incoming signals over the network.
(ii) Repeater takes high input power and provides low input power while amplifier takes low input power and provides high input power.
14. How is a LAN different from a MAN?
Answer :
LAN :
• It stands for Local Area Network.
• These are computer networks that are confined to a localised area( eg. Office or a builiding)
• LAN’s ownership is private.
MAN:
• It stands for Metropolitan Area Network.
• It refers to a network that is spread over an area as big as a city.
• MAN’s ownership can be private or public.
