Physical Layer

Question 1

What must be established before any network communication can occur?

Answer 1

A physical connection to a local network must be established (it could be wired or wireless)

Question 2

What are the purposes of the physical layer?

Answer 2

1. To transport bits across the network media

2. Accepting a complete frame from the Data Link layer and encoding it as a series of signals that are transmitted

Question 3

What is Bandwidth? What can it be impacted by?

Answer 3

1. Bandwidth is the capability at which a medium can carry data
2. It can be impacted by: physical media properties, current technologies, laws of physics

Question 4

What is latency?

Answer 4

It’s the amount of time for data to travel from one given point to another

Question 5

What is the difference between throughput and goodput?

Answer 5

Throughput is the measure of the transfer of bits across the media over a given period of time

Goodput is the measure of usable data transferred over a given period of time ((throughput) - (traffic overhead))

Question 6

What are the benefits of Fibre-Optic cables?

Answer 6

1. Transmits data over longer distances
2. Transmits data at a higher bandwidth
3. EMI/RFI resistent

Question 7

What are the limitations of Wireless Media?

Answer 7

1. Coverage area
2. Interference
3. Security
4. Shared Medium (WLAN operates in half-duplex (many simultaneous users => reduced bandwidth))