RFC:791INTERNETPROTOCOLDARPAINTERNETPROGRAMPROTOCOLSPECIFICATIONSeptember1981preparedforDefenseAdvancedResearchProjectsAgencyInformationProcessingTechniquesOffice1400WilsonBoulevardArlington,Virginia22209byInformationSciencesInstituteUniversityofSouthernCalifornia4676AdmiraltyWayMarinadelRey,California90291September1981InternetProtocolTABLEOFCONTENTSPREFACE........................................................iii1.INTRODUCTION.....................................................11.1Motivation....................................................11.2Scope.........................................................11.3Interfaces....................................................11.4Operation.....................................................22.OVERVIEW.........................................................52.1RelationtoOtherProtocols...................................92.2ModelofOperation............................................52.3FunctionDescription..........................................72.4Gateways......................................................93.SPECIFICATION...................................................113.1InternetHeaderFormat.......................................113.2Discussion...................................................233.3Interfaces...................................................31APPENDIXA:Examples&Scenarios...................................34APPENDIXB:DataTransmissionOrder................................39GLOSSARY............................................................41REFERENCES..........................................................45[Pagei]September1981InternetProtocol[Pageii]September1981InternetProtocolPREFACEThisdocumentspecifiestheDoDStandardInternetProtocol.ThisdocumentisbasedonsixearliereditionsoftheARPAInternetProtocolSpecification,andthepresenttextdrawsheavilyfromthem.Therehavebeenmanycontributorstothisworkbothintermsofconcep