108                            ______________________ Internet

Checksum (16 ).    .

Authentication (16 ).   . , " -
".    OSPF    -
   .     
"   ".

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    OSPF    RFC-1245, RFC-1246,
RFC-1247, RFC-1248, RFC-1427, RFC-1584, RFC-1850.

  EGP, BGP

  Internet    
,          -
      . ,   -
      .

  Internet  .  
     " " (autonomous systems),
        -
   .    -
    GGP    -
    "" Internet.  1984 .,
  ,  Internet   -
    EGP  Exterior Gateway Protocol.

EGP

  EGP    
   AS,       -
     Internet    
.

 ,  EGP     
.       
 AS,      -
  ,       -
.  ,   AS     IGP (RIP 
OSPF), a EGP     AS.  -
,   AS     backbone,
     AS.  , EGP    
  .

,    EGP- Internet   
 ,      ,   -
      AS.   -
   EGP.     