530     6   

  ,      -
 1,     250 720,    -
  250 720 11,     250 720 26.   
 ,    ,     -
,  .

       -
       ( Data).   -
     Call Request        
 ,       .     ,
       ,   , -^
  Protocol  IP-.       
       .

 ()  .25      
       TCP/IP.  -
 ,        
   ,     
   .       -
  ,   .  ,  -
  .25   ,   ,
      .  .25
   LAP-B       LAP-B,  
     .    
      .    -
 LAP-B   ,      .25,  
     ,    
 LAP-B    .   
          ,   
,   .

    .25   -
      .    -
,        (12009600 /),
      .

    .25  . ,   -
 ,       . -
          .

  .25      -
    .      
    ,   .25 
-        
.

6.4.3.  Frame Relay

   

 frame relay    ,     
         .25,