SAR  - Segmentation and Reassembly Layer

SAR - The Segmentation and Reassembly Layer is the lower of two
sublayers (Convergence Sublayer (CS) and SAR) that make up the ATM
Adaptation Layer (AAL) as shown in the diagram below. The SAR is
responsible for mapping data from the AAL Convergence Sublayer into
the cell payloads of an ATM cell stream.


     /------ /|-------------------------------------| 
    /       / |  Common Part Convergence Sublayer   | 
   /       CS |-------------------------------------|
  AAL       \ |Service Specific Convergence Sublayer|
   \         \|-------------------------------------| 
    \     SAR | Segmentation & Reassembly Sublayer  |
     \--------|-------------------------------------|
              |             ATM layer               |
              |-------------------------------------|


AAL: ATM Adaptation Layer
CS : Convergence Sublayer