328     4          

    ( ,    ,  -
  ,     ),    
         
      .   -  
     ,   , -
    ,   ,   ,   -
  ,       
  .     ,    
, .

         
        
,      .

         2 
    2.  2     -
  ,             
10  (         
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 2).      ,   ( 
  ),       -
 2.

     ,       -
 2,  2 ,         -
     0 (      
 1).        2  -
   10,         2.

  ,    ,   -
   .     
.

       
  BPDU,      
     .   -
   ,    2  4,     -
      Spanning Tree,  
  .    -    -
      BPDU,    
   ,     -
 BPDU   .   ,  -
    BDPU  ,  
    .

   

       
 ,  Ethernet  FDDI, Fast Ethernet  Token Ring  . .  
     ,    ,    -
   IEEE 802.1  RFC 1042,  
    .