Digi'al Solutions Flashcards
Cuppa Tea (30 cards)
What does ‘OSI’ stand for in the OSI Model?
‘Open Systems Intercommunication’
What is the first layer of the OSI Model and what is it for?
Physical Layer:
- Defines electrical & physical connections between devices
- E.g. voltage, cables, timings
What is the second layer of the OSI Model and what is it for?
Data Link Layer:
- Protocol layer in a program
- Handles the movement of data in and out of a physical link or network
What is the third layer of the OSI Model and what is it for?
Network Layer:
- Allows the transfer of data between two different nodes within separate networks
What is the fourth layer of the OSI Model and what is it for?
Transport Layer:
- Allows for transferring of variable-length data sequences between sources
- Between applications or across a network connected physically or wirelessly
What is the fifth layer of the OSI Model and what is it for?
Session Layer:
- Maintains controlled connection between multiple computers
- Connection is called the ‘session’
- Initiates and terminates the session
What is the sixth layer of the OSI Model and what is it for?
Presentation Layer:
- Transforms data so it can be read by the application
What is the seventh layer of the OSI Model and what is it for?
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
What is latency and what factors affect it?
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
What is verification?
Verification attempts to ensure that stored data is accurate (DOB can’t be in the future)
What is bandwidth and how does it affect data transmission?
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).
What is validation?
Validation is ensuring the data is inputted correctly. (Phone number has only numbers)
What is throughput?
Throughput is the amount of data that can be transferred over a given period of time. Measured in bits per second (bps).
What is accessibility?
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.
What is round-trip time?
Round-trip time (RTT) is the time (milliseconds) it takes for a packet to be sent, received and sent back again.
What is effectiveness
Effectiveness
What is jitter and what is it caused by?
Jitter is the variation in time (± milliseconds) between receiving data packets. Caused by network congestion or route changes.
What is Quality of Service Guarantee?
QoS Guarantee is mechanisms that guarantee priority transmissions on network-connected devices through bandwidth reservation. Prevents communication delays.
