Performance of Networks

Question 1

What is the speed of a network measured in?

Answer 1

bits per second

Question 2

What does bandwidth mean?

Answer 2

How much data can be transferred over a connection in a given time

Question 3

What does contention ratio mean?

Answer 3

Ratio of users compared to available bandwidth

Question 4

Which type of ethernet cable is faster, Cat-5 or Cat-6?

Answer 4

Cat-6

Question 5

How do fibre optic cables work?

Answer 5

Transfer data using light which is reflected along the inside of the cable

Question 6

What is the bandwidth like for fibre optic cables?

Answer 6

High

Question 7

What is meant by a backbone?

Answer 7

A backbone joins together a number of LANs in the same building or as part of a WAN and the backbone is expected to carry heavy data traffic

Question 8

What frequency bands does Wi-Fi work at?

Answer 8

2.4GHz

5GHz

Question 9

What is a band?

Answer 9

A range of frequencies

Question 10

What 3 factors limit Wi-Fi performance?

Answer 10

Radio Interference
Blocked by walls
Limited connections

Question 11

What 2 main reasons are there for ‘errors’ happening?

Answer 11

Interference

Signal is too weak

Question 12

What is latency a technical word for?

Answer 12

Delay

Question 13

What is the correlation between the size of the network and the latency?

Answer 13

The larger the network, then the longer it takes for a bit to travel from one point to another (Higher latency)

Question 14

What is performance affected by on wired networks?

Answer 14

Type of cable connection (Ethernet or fibre optic)
Bandwidth available
Contention ratio
Error rates
Latency

Question 15

What is performance affected by on wireless (Wi-Fi)networks?

Answer 15

The band chosen
Number of channels available to assign
Interference from sharing channels with other devices
Interference from Non-Wi-Fi devices emitting signals on the same frequency
Physical layout; solid walls block signals, signals get weaker over distances

Question 16

State 7 important things about wired networks

• Cost
• Log in
• Radio
• Bandwidth
• Security
• Building
• Portability

Answer 16

More costly than Wi-Fi to install in a building
Allows hundreds of people to log in at the same time
Immune to radio interference
High bandwidth
Excellent security
Not affected by building layout
Not portable

Question 17

State 7 important things about wireless networks

• Cost
• Log in
• Radio
• Bandwidth
• Security
• Building
• Portability

Answer 17

Only needs a Wireless Access Point to set up, so is cheaper
Allow a limited number of people to connect at any one time
Affected by radio interference
Lower bandwidth
Not so secure as connection is by radio
Signal is affected by walls and floors
Very mobile