Lernkarten

Subhan Waizi
Karten 12 Karten
Lernende 0 Lernende
Sprache English
Stufe Universität
Erstellt / Aktualisiert 21.09.2016 / 21.09.2016
Lizenzierung Kein Urheberrechtsschutz (CC0)
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0 Exakte Antworten 12 Text Antworten 0 Multiple Choice Antworten
Fenster schliessen

Give a general description of the ISO/OSI reference model.

The ISO/OSI model is a hierarchical model that describes the structure of more complex communication systems. It structures communication systems by distributing the functionality among different layers. Every open communication model is made out of layers, where each layer is responsible for a certain task of the whole comunication. This reference model helps both to increase clarity and decrease complexity. Note that a layer in the hierarchy may only make use of functions of the layer that lies directly under it and may only provide functions to the layer that is situated directly above it.

n+1

n uses functions of n-1 and provides functions to n+1

n-1

Fenster schliessen

State the seven layers of the ISO/OSI reference model. What does OSI stand for?

OSI stands for Open Systems Interconnection Model. The seven layers in the model from top to bottom are

Anwendung (Application)

Presentation (Darstellung)

Session (Sitzung)

Transport (Transport)

Network (Vermittlung)

Data Link Layer (Sicherungsschicht)

Physical Layer (Physikalische Schicht)

Fenster schliessen

Describe the functionality of the physical layer of the ISO/OSI model.

The physical layer is the bottom layer of the model. It defines the physical attributes of a connection, i.e. connector types, wire types and transmission medium. Furthermore it is responsible for information coding (signal levels) on the bus.

Fenster schliessen

Describe the functionality of the second layer of the ISO/OSI model, i.e. the data link layer.

  • open and maintain a connection
  • defines bus access methods
  • structures telegrams and marks start and end of frame
  • inserts functionality for transmission error detection (CRC, Repetition, Frames)
Fenster schliessen

Describe the functionality of the third layer of the ISO/OSI model, i.e. the network layer.

  • Set-Up of a communication route (routing) in distributed networks according to certain design goals, i.e. shortest paths (distance), low-cost paths, minimum latency paths ...
  • Counteracts overloads on single routing paths
  • Intermediate storage of data until all packages arrive 
  • enables peer-to-peer connections (builds packages, routing, routing protocols)
Fenster schliessen

Describe the functionality of the fourth layer of the ISO/OSI model, i.e. the transport layer.

  • shields details of data transport
  • corrects transmission errors
  • segments long messages into packages
  • sorting packages in right order upon receival 
  • reacts to repeat requests
Fenster schliessen

Describe the functionality of the fifth layer of the ISO/OSI model, i.e. the session layer.

  • provides services for opening and closing a connection
  • monitors and supervises the data flow of a connection
  • provides a universal transport service
Fenster schliessen

Describe the functionality of the second last layer of the ISO/OSI model, i.e. the presentation layer.

  • clear data interpretation of received data
  • data encryption and decryption
  • handles data access of different applications