CO526 Distributed Systems and Networks

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  1. State the name of each layer in the ISO seven-layer model
    • Layer 7 - Application
    • Layer 6 - Presentation
    • Layer 5 - Session
    • Layer 4 - Transport
    • Layer 3 - Network
    • Layer 2 - Data Link
    • Layer 1 - Physical
  2. Give some disadvantages of standardizing
    • Standardizing when research is incomplete, thus leading to poor standards.
    • Standards can be overly complex and thus restrictive on new people entering the market.
    • Standards may be incomplete.
    • Standards may become irrelevant as technology advances.
  3. State the purpose of the Physical layer in ISO seven-layer network model.
    Bit transmission across some sort of transmission meidum
  4. State the purpose of the Data Link layer in ISO seven-layer network model.
    Blocking bits together to control flow and checking that they arrived correctly
  5. State the purpose of the Network layer in ISO seven-layer network model.
    Routing blocks of bits through a network
  6. State the purpose of the Transport layer in ISO seven-layer network model.
    Receives the blocks at the destination (and passes them to the right application)
  7. State the purpose of the Session layer in ISO seven-layer network model.
    Synchronization and Dialogue control. Managing sessions between applications.
  8. State the purpose of the Presentation layer in ISO seven-layer network model.
    Syntax and semantics of the information. (Encrypting / Decrypting, Data representation)
  9. State the purpose of the Application layer in ISO seven-layer network model.
    Common applications
  10. Name the internet layers
    • Application Layer
    • Transport Layer
    • Internet Protocol Layer
    • Network Interface Layer
    • Physical Net Layer
  11. Which layers of the Intenet model correspond with that of the OSI seven-layer model.
    • Internet Application - OSI Application
    • Internet Application - OSI Presentation
    • Internet Application - OSI Session
    • Internet Transport - OSI Transport
    • Internet Internet Protocol - OSI Network
    • Internet Network Interface - OSI Data Link
    • Internet Physical - OSI Physical
  12. Why is layering (abstraction) a good idea?
    • Focus on the individual processes
    • Debugging and maintenance is easier
  13. What is a protocol?
    "A set of rules and regulations agreed by two parties in order to govern communication."
  14. What is framing and why is it used?
    It is where a raw bit stream is broken up into groups of bits (called frames). This is to enable error and flow control.
  15. Data Link Protocol: What would be an unrestricted protocol?
    A protocol whereby the sender could send frames as fast as it wanted. (Unrestricted send speed)
  16. Data Link Protocol: What would be a restricted protocol?
    • (Stop-and-wait protocol)
    • Sender sends a frame and then waits for an acknowledgement (ACK)
    • Receiver waits for a frame and then sends an acknowledgement (ACK) when it has received one.
  17. Data Link Protocol: What is put in place to help tackle a noisy channel?
    • Sender times out if it doesn't receive an acknowledgement (ACK). It will then re-send the same frame.
    • We use sequence numbers so that the receiver can check that the expected frame has been received. The receiver then sends an acknowledgement (ACK) back to the sender.
Author:
Anonymous
ID:
212856
Card Set:
CO526 Distributed Systems and Networks
Updated:
2013-04-11 13:44:19
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Distributed Systems Networks
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Revision cards for CO526 Distributed Systems and Networks
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