Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 1: Introduction (Use of Computer Network (Business Applications,…

- - - - Bus:only one computer can sent at a time
      - Ring:can send at the same time
- - - - Connection-Oriented services
        
        Eg telephone service
        
        Service 1:message stream
        
        Sequence important:reliable message stream
        
        Service 2:byte stream
        
        Reliable byte stream:remote login
        
        Unreliable connection:digitized voice
      - Connectionless services
        
        Eg postal service
        
        Unreliable datagram:junk mail
        
        Acknowledged datagram:registered mail
        
        Request-reply:database query
- - - - Crest layer when different abstraction needed
      - Each layer perform well defined function
      - Function of each layers match internationally standardised protocol
      - Layer boundary should minimise the information flow
      - Number of layer should be enough
    - - Physical
        
        Transmit raw data over a communication channel
      - Data Link
        
        Transform a raw transmission facility into a line that appears free of undetected transmission error
      - Networktext
        
        Control the operation of subnet, determines the route b/w source and destination
      - Transport
        
        Accept data from session then spilt into smaller units
      - Session
        
        Allow different machines to establish sessions
      - Presentation
        
        Concerned with the syntax and semantics of information
      - Application
        
        Contain protocols needed by users
    - - Bad timing
      - Bad technology
      - Bad implementations
      - Bad politics
  - - - Services
      - Interfaces
      - Protocols