Networks amd the internet

Question 1

what is a local area network

Answer 1

a network which consists of a number of computing devices on a single site or in a single businesses

Question 2

what is a bus topology

Answer 2

where all computers are connected to a single cable. the ends of the cable are plugged into a terminator

Question 3

advantages of bus topologies

Answer 3

cheaper to install as it requires less cable than a star topology and does not require any additional hardware

Question 4

disadvantages of bus topology

Answer 4

• if main cable fails, network data can’t be transmitted to any of the nodes
• performance degrades with heavy traffic
• low security as all computers in the network can see all data transmissions

Question 5

what is a physical star topology

Answer 5

one that has a central node, which may be a switch or computer, which acts as a router to transmit messages

Question 6

advantages of a star topology

Answer 6

• if one cable fails, only one station is affected, so it’s easier to isolate faults
• consistent performance even when network is being heavily used
• higher transmission speeds give better performance than a bus network
• no problems with collisions as each station has its own cable to the server
• system is more secure as messages are sent directly to the central computer and cannot be intercepted by other stations
• easy to add new stations without disrupting the network

Question 7

disadvantages of a star topology/network

Answer 7

• may be costly to install because of the length of cable required
• if the central device goes down, network data can no longer be transmitted to any of the nodes

Question 8

what is the node connected to on a star topology

Answer 8

a central device , typically a switch

Question 9

what does a switch do

Answer 9

it keeps a record of the unique MAC address of each device on the network and can identify which particular computer on the network it should send the data to

Question 10

difference between physical and logical topology

Answer 10

• the physical topology of a network is its actual design layout
• the logical topology is the shape of the path the data travels in, and describes how components communicate across the physical topology

Question 11

how can we make a star topology act like a bus one

Answer 11

• use a bus protocol
• Use a central device that acts as a simple hub instead of a switch
• Ensure that all devices connected to the hub share the same communication medium
• Implement a collision detection and handling mechanism, such as (CSMA/CD), to manage simultaneous data transmissions and collisions,

Question 12

operation of a logical bus network

Answer 12

• data cannot be simultaneously transmitted in both directions (duplex transmission not possible)
• each station receives all network traffic
• the traffic generated by each station has equal transmission priority

Question 13

what is an MAC address

Answer 13

an address which is assigned into a card and uniquely identifies a device
- 48 bits long and is written as 13 hex digits

Question 14

used of mac addresses

Answer 14

tracking people

Question 15

what is a client server network

Answer 15

• computers are nominated as clients and one or more as servers. The clients request services from the servers, which provide these services, for example file server, email server.

Question 16

advantages of a client-server network

Answer 16

• security is better since all files are stored in a central location and access rights are managed by the server
• backups are done centrally so there is no need for individual users to back up their data
• if there is a breakdown and some data is lost, recovery procedures will enable it to be restored
• data and other resources can be shared

Question 17

disadvantages of client-server network

Answer 17

• expensive to install and manage
• professional IT staff are needed to maintain the servers and run the network

Question 18

what is peer to peer network

Answer 18

• there is no central server
• individual computers are connected to each other, either locally or over a wide area network so that they can share files
• each computer has equal status

Question 19

advantages of peer to peer

Answer 19

• cheap and easy to set up
• enables users to share resources such as a printer or router
• no centralised server, if one peer fails, others can still use the network

Question 20

examples of when peer to peer is used

Answer 20

video on demand- hundreds of computers can be used to hold part of the video and share the load
- file transfer
- wireless printing
- bluetooth speakers

Question 21

disadvantages of peer to peer

Answer 21

piracy
- no central management, updates for the software are harder
- file duplication
- peers may lose connection easily

Question 22

why is peer networking used for piracy

Answer 22

because it’s impossible to trace the files which are being illegally downloaded

Question 23

consequences of piracy

Answer 23

• the more movies that stolen and illegally downloaded, the fewer resources movie makers have to invest in new films

Question 24

what is wifi

Answer 24

a local area wireless technology that enables you to connect a device to a network resources or to the internet via a WAP

Question 25

how to connected to a wireless network

Answer 25

• a computer needs a wireless network adaptor
• all stations share a single radio frequency communication channel
• each station is constantly turned in on the frequency to pick up transmissions
• transmissions are received by all the stations within range of the WAP
• to connect to the internet , the WAP usually connects to a router

Question 26

what is a station

Answer 26

the combination of computer and interface controller

Question 27

why is serial transmission favoured over long distances

Answer 27

• eliminates the risk of desynchronisation
• bits are transmitted simultaneously and may arive at different times

Question 28

what is a network

Answer 28

a collection of connected computers

Question 29

describe the logical operation of a bus topology

Answer 29

A node broadcasts data (to the entire network);
All/Any nodes on the network receive/read the data;
A node examines the received data to check if it is the intended recipient;
Only one node can (successfully) transmit data at a time // Nodes use a shared
transmission medium

Question 30

how can bit rate be higher than baud

Answer 30

Bit rate can be higher than baud rate if more than one bit is encoded in each signal
change;