 2.   TCP/IP___________________________101

Metric (32 ).       (hop
count)    () ,   
    .

    RIP     25  -
.        
   RIP.

    - 
,    RIP,    RFC-1058, RFC-1075,
RFC-1102.

   OSPF

   OSPF,    -
   IGP  .

OSPF     ,   -
    (Open Shortest Path Fisrt  OSPF). -
     IP   IETF (Internet
Engineering Task Force,    
Internet),     
IGP.      1988 .   
IGP,    "  " (shortest
path first  SPF),       Internet. -
   OSPF    RIP  -
   .

   , OSPF    : -
  , . .     -
,     SPF.  SPF  
 Dijkstra    .

OSPF      
    (link-state).     -
      AS (Autonomous System),  -
     ,   -
        
   .   
    AS OSPF  IP-.

     AS  OSPF 
       
    (link-state advertisement  LSA). 
    ,   
            AS,  
     AS.  LSA- 
OSPF     ,  
   .     OSPF -