Digi'al Solutions

Question 1

What does ‘OSI’ stand for in the OSI Model?

Answer 1

‘Open Systems Intercommunication’

Question 2

What is the first layer of the OSI Model and what is it for?

Answer 2

Physical Layer:
- Defines electrical & physical connections between devices
- E.g. voltage, cables, timings

Question 3

What is the second layer of the OSI Model and what is it for?

Answer 3

Data Link Layer:
- Protocol layer in a program
- Handles the movement of data in and out of a physical link or network

Question 4

What is the third layer of the OSI Model and what is it for?

Answer 4

Network Layer:
- Allows the transfer of data between two different nodes within separate networks

Question 5

What is the fourth layer of the OSI Model and what is it for?

Answer 5

Transport Layer:
- Allows for transferring of variable-length data sequences between sources
- Between applications or across a network connected physically or wirelessly

Question 6

What is the fifth layer of the OSI Model and what is it for?

Answer 6

Session Layer:
- Maintains controlled connection between multiple computers
- Connection is called the ‘session’
- Initiates and terminates the session

Question 7

What is the sixth layer of the OSI Model and what is it for?

Answer 7

Presentation Layer:
- Transforms data so it can be read by the application

Question 8

What is the seventh layer of the OSI Model and what is it for?

Answer 8

Application Layer:
- Allows users to interact directly with software application
- Software application must implement a component of communication between the client and server, e.g. File Explorer or Word

Question 9

What is latency and what factors affect it?

Answer 9

Latency is the time (milliseconds) it takes for data to travel from one source to another . It is affected by:
- Bandwidth
- Propagation (Travels at light-speed)
- Routers
- Storage delays

Question 10

What is verification?

Answer 10

Verification attempts to ensure that stored data is accurate (DOB can’t be in the future)

Question 11

What is bandwidth and how does it affect data transmission?

Answer 11

Bandwidth is the width of an electrical cable. The narrower it is, the less data can travel through it at any given moment. Measured in bits per second (bps).

Question 12

What is validation?

Answer 12

Validation is ensuring the data is inputted correctly. (Phone number has only numbers)

Question 13

What is throughput?

Answer 13

Throughput is the amount of data that can be transferred over a given period of time. Measured in bits per second (bps).

Question 14

What is accessibility?

Answer 14

Accessibility guidelines provide organisations with recommendations to provide a good experience for marginalised users. Such as improving the way screen readers describe pages for the blind.

Question 15

What is round-trip time?

Answer 15

Round-trip time (RTT) is the time (milliseconds) it takes for a packet to be sent, received and sent back again.

Question 16

What is effectiveness

Answer 16

Effectiveness

Question 17

What is jitter and what is it caused by?

Answer 17

Jitter is the variation in time (± milliseconds) between receiving data packets. Caused by network congestion or route changes.

Question 19

What is Quality of Service Guarantee?

Answer 19

QoS Guarantee is mechanisms that guarantee priority transmissions on network-connected devices through bandwidth reservation. Prevents communication delays.