communication and networking

Question 1

Serial transmission

Answer 1

Data flows through a signal line

Question 2

Parallel transmission

Answer 2

Data flows through multiple lines

Question 3

Why serial transmission is better than parallel

Answer 3

Cheaper as less wire is required

bandwidth is higher

Question 4

Synchronous data transmission

Answer 4

Where the pulse of the clock of the sending and receiving devices are in time with each other. They might share a common clock

Question 5

Asynchronous data transmission

Answer 5

Data is transmitted between two devices that do not share a common clock signal

Question 6

compare synchronous with asynchronous data transmission

Answer 6

Asynchronous: Receiver and transmitter are not synchronised by a common clock

Synchronous: Receiver and transmitter continuously synchronised by a common clock

Question 7

purpose of start and stop bits in asynchronous data transmission.

Answer 7

Indicates to the receiving device when the data transmission begins and ends

Question 8

baud rate

Answer 8

Number of signal changes in the medium in a second

Question 9

Bandwidth

Answer 9

Range of frequencies that can be transmitted across a network connection

Question 10

Bit rate

Answer 10

Number of bits transferred between devices in one second

Question 11

latency

Answer 11

rate at which signals on a wire change

Question 12

protocol

Answer 12

Set of rules

Question 13

Differentiate between baud rate and bit rate.

Answer 13

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

Question 14

relationship between bit rate and bandwidth.

Answer 14

Bit rate is directly proportionate to bandwidth.

Question 15

Physical star topology

Answer 15

How nodes are physically laid out

Question 16

Logical star topology

Answer 16

How data flows through a network

Question 17

How can a network physically wired in a star topology behave logically as a bus network

Answer 17

By using a bus protocol and appropriate physical switching

Question 18

pros and cons for peer to peer and where it might be used

Answer 18

Doesn’t need a central server and easier to set up as no server to configure and cheap as there is no need for server
Less secure and speed of one machine can affect other machines in a network

file sharing

Question 19

pros and cons for peer client server

Answer 19

Faster access speed and more secure
Client is dependant on the server

web apllications, emails

Question 20

peer to peer

Answer 20

each computer has equal status
resources stored on or shared from any computer
no reliance on central server

Question 21

client server

Answer 21

most computers are nominated as clients and one or more as servers
client access resources from server
reliance on central server

Question 22

Explain the purpose of WiFi.

Answer 22

A wireless local area network that is based on international standards.

Used to enable devices to connect to a network wirelessly

Question 23

components required for wireless networking.

Answer 23

Wireless network adapter.

Wireless access point.

Question 24

how wireless networks are secured

Answer 24

Strong encryption of transmitted data using WPA/WPA2, SSID broadcast disabled, MAC address white list.

Question 25

explain the wireless protocol Carrier Sense Multiple Access with Collision Avoidance

Answer 25

computer with data to send monitors/listens for (data signal)
if (data) signal present transmission in progress then continue to wait
when no (data) signal present computer sends a Request to Send / RTS
two computers could start transmitting simultaneously if they both detect there is no data signal

receiver responds (to RTS) with a Clear to Send signal
RTS/CTS signal blocks any other transmissions from nodes in range
when CTS received then start to transmit
if CTS not received continue to wait
receiver sends acknowledgement after (all) data received

Question 26

purpose of Service Set Identifier (SSID)

Answer 26

to identify a specific wireless network

Question 27

operation of ssid

Answer 27

data is stored electronically
data is stored in floating gate transistors
data is organised into blocks
a block must be erased before it can be overwritten

Question 28

structure of internet

Answer 28

application layer:
Selects and uses the correct protocol to transmit data

transport layer:
an end to end connection between the sender and the receiver. The layer then splits the transmission into packets.

network layer:
Provides the correct IP addresses for each packet’s source and destination

link layer:
Controls physical connections between pieces of hardware in a network. Adds MAC addresses to packets which it receives from the network layer. The MAC addresses identify the hardware to which a packet should be sent

Question 29

main components of a packet

Answer 29

header: contains information about the packet (origin and destination ip adress)

payload: actual data

Question 30

router and its use

Answer 30

device used to direct packets being transmitted between networks

used in local area networks

Question 31

gateway and its use

Answer 31

device that allows data to flow from one network to another

Connecting a LAN to the internet

Question 32

Compare and contrast thin-client computing with thick-client computing

Answer 32

processing is carried out

clients are cheaper to purchase
workstations need less maintaining

Question 33

Compare JSON (Java script object notation) with XML

Answer 33

easier for a human to read
more compact
easier to create
easier for computers to parse and therefore quicker to parse