542     6   ___________________________ ___

   Forum      -
    ,  -
  ,     
.        -
    5-10 .       
   ,       
  ,      ,  -
 ,       .  ,  
        
,  ,   .

   

         -
       
,          -
.    20-    
      .  
     PNNI (Private NNI),  
      . 
       -
 /    .25,     PNNI.

       -
 (Virtual Channel Identifier, VCI),     
     .    ,
     ,   -
,     ,   , 
 , ,     . .,   -
   ,     
IP-     CIDR.

     (Permanent Virtual Circuit,
PVC)   (Switched Virtual Circuit, SVC).   -
         Virtual Path,
   ,    
          -
   .    (Virtual Path
Identifier, VPI)        
       . -
 ,         
       (   
 )       ( 
     ).

        -
  UNI (User Network Interface).  UNI  -
 ,  ,   ,  
,        .
     UNI ,4^   ,
  ,   UNI 3.1.