Computer Network - Mu Lesson 2 notes

Computer Network Architecture -OSI hierarchical model

• Host computer
• router
• Various link
• application
• protocol
• Hardware, software
• ……

Each complete a particular feature, services, and do not control the underlying upper layer, interaction between the layers of the SAP

• The application layer
  supports the user by user agents (such as a browser) or network interface
  using network (service)
  • FTP file transfer
  • SMTP e-mail
  • HTTP Web
  Architecture: client / server, p2p, hybrid structure
  requirements: reliability, bandwidth, delay
  Socket Programming
• Presentation layer
  issues the syntax and semantics of the two processing systems
  • Data representation conversion
  • encrypt and decode
  • Compression, decompression

• Session layer
  dialog control, synchronization, function weakest

• Transport layer
  is responsible source to destination (process) of complete message transmission, segment data segment
  • Segmentation and Reassembly
  • Connection Control
  • Error Control
  • flow control
  • Examples: TCP, UDP
• Network layer
  data source host to the destination host to deliver packet data packet
  logically addressed: globally unique logical address, the data packet is delivered to ensure that the destination host, such as IP address
  • Route: Path Selection
  • Packet forwarding
• Data link layer
  transmission between the node and the node, Frame frame , increasing the physical address
  flow control, error control, access (access) control
  • Ethernet
  • WiFi
  • PPP

• The physical layer
  interface characteristics, shape, voltage, function, during operation
  only concerned bit transfer

Each layer to be encapsulated

• Increasing the control-PDU information (user data control information +)
  • Address - identifies the sending end, the receiving end
  • Error detection coding
  • Control Protocol - the protocol functions to achieve additional information, priority, quality of service, security control