Open Systems Interconnection (OSI) model

Question 1

What are the main purposes of the OSI networking model?

Answer 1

• Standardisation
• Modularity

Question 2

acronym for layers

Answer 2

A PSTN DP

A Piston DisplayPort

Application, Presentation, Session, Transport, Network, Datalink, Physical — in reverse (lowest to highest level)

Question 3

Layer

Physical

(Layer 0)

Answer 3

Hardware – Physical connections

Question 4

Layer

Datalink

(Layer 1)

Answer 4

The link between host(s)/router(s)

Question 5

Layer

Network

(Layer 2)

Answer 5

Packet routing

Question 6

Layer

Transport

(Layer 3)

Answer 6

E2E (end-to-end) communication — packet transport.

Question 7

Layer

Session

(Layer 4)

Answer 7

Manages connection sessions (keepalives and whatnot)

Question 8

Layer

Presentation

(Layer 5)

Answer 8

Encryption, compression, etc — e.g. converting RAW file to JPEG for easier transmission

Question 9

Layer

Application

(Layer 6)

Answer 9

The highest level layer controlled directly by the application.