Designation:F1757−96(Reapproved2015)AnAmericanNationalStandardStandardGuideforDigitalCommunicationProtocolsforComputerizedSystems1ThisstandardisissuedunderthefixeddesignationF1757;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Theprincipalcontentofthisguideprovidesaroadmaptoimplementacommunicationnetworkapplicabletoshipandmarinecomputersystemsby:1.1.1Examiningtherelationshipofdigitalcommunicationprotocolsasanetworktechnologicalinfrastructure,1.1.2Outliningthebasicbuildingblocksofnetworktopolo-giesandtransmissiontechniquesassociatedwiththeimple-mentationoftransmissionmediainanetworkenvironment;and,1.1.3Identifyingoperatingsystemandenvironments.1.2UsingtheOpenSystemInterconnection(OSI)model,whichprovidesalayeredapproachtonetworkfunctionalityandevaluation,commonnetworkcommunicationsprotocolsareidentifiedandcharacterizedinthisguideaccordingtolowerandupperlayerprotocolscorrespondingtotheirdegreeandtypeoffunctionality.1.3Althoughitisdesirablethatnetworkusers,designers,andadministratorsrecognizeandunderstandeverypossiblenetworkingprotocol,itisnotpossibletoknowtheintimatedetailsofeveryprotocolspecification.Accordingly,thisguideisnotintendedtoaddressfullyeveryhardwareandsoftwareprotocoleverdevelopedforcommercialuse,whichspansaperiodofabout25years.Instead,theuserofthisguidewillbeintroducedtoabriefoverviewofthemajorityofpastandpresentprotocolswhichmaycompriseashipormarineinternetwork,toincludeLocalAreaNetworks(LANs),WideAreaNetworks(WANs),andrelatedhardwareandsoftwarethatprovidesuchnetworkinteroperabilityanddatatransfer.1.4Whilethisguideprovidesanunderstandingofthewiderangeofcommunicationprotocols,theuserisrecommendedtoconsultthereferencematerialforacquiringamorecompre-hensiveunderstandingofindividualcommunicationprotocols.However,byexaminingthebasicfunctio...
