6.4.            531

,     ,    -
      ,     
      - -
.

  frame relay      -
    ,    
    .    -
 frame relay  .  frame relay   
      .  
    2 /.

  frame relay    -
        -
         
.   frame relay     
    ,      
        -
  (best effort),    .

 frame relay   ISDN   .  -
 1.122,     1988 ,      -
   ,       
1992-93 .     frame relay      
     frame switching.  frame switching -
        .  -
       frame
relay.

 frame relay      -
     .    
  CCITT (ITU-T)    Frame Relay
Forum   T1S1  ANSI.

  Frame Relay Forum   1990  -
 Cisco Systems, StrataCom (   Cisco Systems), Northern
Telecom  Digital Equipment Corporation     
CCITT  ANSI.  Frame Relay Forum   FRF  
 .  FRF     -
 frame relay,         ITU-T  ANSI.
,  FRF.11       frame
relay.

 Frame Relay Forum  ,  -
   frame relay,  T1S1  CCITT. 
   ,   
     ,     -
  frame relay     .  
 frame relay   Local Management Interface (LMI)  
 .

 ITU-T       
 ,      . -
 Frame Relay Forum     ITU-T 
  . ,  frame switching  