6.4.            551

    ,  -
     ,    AAL.   
  (  ,  
)   ,   ,  , 
  QoS.       -
 QoS:       , -
          . 
    ,      
        -
    .

      QoS 
AAL  .    -  -
       .  -
   ,    
      .

 

          ,  -
 IP   TCP/IP   LAP-F     frame
relay.         -
    ,     
  .      
 ,          -
   (Virtual Path Identifier, VPI)   -
  (Virtual Channel Identifier, VCI).    
         -
    ,  -, -
 -   ,    
     (,   -
 -    ).

      ,  
. 6.32.

   (Generic Flow Control)    -
      .    
   .

    (VitualPath Identifier, VPI)  -
   (Vitual Channel Identifier, VCI)  -
 1  2 .      , 
  (VPI)   (VCI) .

    (Payload Type Identifier, PTI)  
3-     ,  ,    -
 (,    ).
 ,            
 Explicit Congestion Forward Identifier, EFCI      , 
 FECN   frame relay,       
  .

    (Cell Loss Priority, CLP)    -
   ,    DE   frame relay     
 ,       -