532     6   

    FRF,    
     FRF ,   
ITU-T,    .

 frame relay,  ITU-T/ANSI,   Frame Relay Forum, 
      (PVC)   (SVC). 
  ,    ,  
   ,    ,   -
,        ,  
 .

   frame relay     frame
relay       . , ,
   .       -
,    , ,  -
 ,   .

  frame relay

 frame relay       -
,  ,     .25,   -
 frame relay   (   )
      ,      
.25        -
 3- .

 ,    LAP-F   frame relay  
    (core)   (control).   ,
      frame relay,  -
    ,      . 
   frame relay    ,  
     ,     -
 *     ,
     .25.     frame relay
     .

 ()    
(signaling)         (D, , )

 (D)
(signaling)

Q.931/Q.933	   (IP, NetBEUI, SNA)			(D, , )	Q.931/Q.933
				LAP-P control Q.922	
LAP-0 Q.921					LAP-D Q.921
	LAP-F core Q.922			LAP-F core Q.922	
  1.430/431			  1.430/431
			

                 S/T                   
. 6.25.   frame relay