6.4.            549

  AAL

  ( Adaptation Layer, AAL)    -
 AAL1-AAL5,      
      .    
      OSI, 
  TCP  UDP.  AAL   -
        (. . 6.31),   -
   .

   AAL    -
 .       
   AAL,       
        
        
.         -
     AAL ,    -
           AAL.

     .  
AAL      (Segmentation And
Reassembly, SAR).        AAL (, ,
   )    () -
,  AAL    ,   , -
          
.

  AAL     Convergence
Sublayer, CS.       . 
    , , ,  -
       ( ,
  ),     -
    ,   -
    (.25, frame relay).

 AAL       -
,     AAL.   , 
  ,  SAR  AAL   
   (        -
 )    AAL,     
,     48-   ,   -
    .     -
 AAL        AAL   
      .

    AAL     
       . -
,    AAL,        -
.            ,
       .  -
  (   )   -
 ,       .