ATM technology (10)

• ATM Layer defines:

  • the structure of ATM cell: cell 53 bytes (5 + 48)
  • virtual channel and path switching
  • UNI and NNI formats; and error control

• ATM Adaptation Layer:

  • converges packets from upper layers into ATM cells
  • AAL types and classes
    • AAL1 - connection-oriented, constant bit rate (CBR), good for audio and video; class A
    • AAL2 - connection-oriented, variable bit rate (VBR), good for compressed video; not implemented; class B
    • AAL3/4 - variable bit rate (VBR), timing not required; class C or D
    • AAL5 - connection-oriented, variable bit rate (VBR), timing not required; subset of AAL3/4; popular implementation; class C

Previous slide

Next slide

Back to first slide

View graphic version