Requirements for Internet gatewaysdraft RFC 985.docx
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Requirements for Internet gatewaysdraft RFC 985.docx
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RequirementsforInternetgatewaysdraftRFC985
Documenttype:
RFC-Unknown(LegacyStream)
ObsoletedbyRFC1009
Published:
1986-05
Otherversions:
plaintext,pdf,html
IPRDisclosures|DependenciestothisRFC
NetworkWorkingGroupNetworkTechnicalAdvisoryGroup
RequestforComments:
985NSF
May1986
RequirementsforInternetGateways--Draft
StatusofthisMemo
ThisRFCsummarizestherequirementsforgatewaystobeusedon
networkssupportingtheDARPAInternetprotocols.Whileitapplies
specificallytoNationalScienceFoundationresearchprograms,the
requirementsarestatedinageneralcontextandarebelieved
applicablethroughouttheInternetcommunity.Thisdocumentwas
preparedbytheGatewayRequirementsSubcommitteeoftheNSFNetwork
TechnicalAdvisoryGroupincooperationwiththeInternetActivities
Board,InternetArchitectureTaskForceandInternetEngineeringTask
Force.Itrequestsdiscussionandsuggestionsforimprovements.
Distributionofthismemoisunlimited.
Thepurposeofthisdocumentistopresentguidanceforvendors
offeringproductsthatmightbeusedoradaptedforuseinan
Internetapplication.Itenumeratestheprotocolsrequiredandgives
referencestoRFCsandotherdocumentsdescribingthecurrent
specifications.Inanumberofcasesthespecificationsareevolving
andmaycontainambiguousorincompleteinformation.Inthesecases
furtherdiscussiongivingspecificguidanceisincludedinthis
document.SpecificpolicyissuesrelevanttotheNSFscientific
networkingcommunityaresummarizedinanAppendix.
*********************************************************************
ThisisaDRAFTeditionofthisstatementofgatewayrequirements.
Commentsaresoughtonthisdocumentforconsiderationand
possiblyincorporatedinthefinaledition.Commentsare
especiallysoughtfromthoseactuallydevelopinggateways,
particularvendorsandpotentialvendorsofgateways.Theperiod
forcommentsis90daysending15-Aug-86,atwhichtimerevised
editionwillbeissuedwithanewRFCnumber.
*********************************************************************
Suggestionsandcommentsonthisdocumentcanbesenttothe
subcommitteechairmanDaveMills(mills@usc-isid.arpa),orNTAG
committeechairmanDaveFarber(farber@huey.udel.edu).The
subcommitteemembers,presentaffiliationsandInternetmailboxesare
asfollows:
HankDardy,NRLdardy@nrl.arpa
DaveFarber,UDelawarefarber@huey.udel.edu
DennisJennings,JVNCjennings%pucc.bitnet@wiscvm.wisc.edu
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RFC985May1986
RequirementsforInternetGateways--DRAFT
LarryLandweber,UWisconsinlandweber@rsch.wisc.edu
TonyLauck,DECrhea!
bergil!
lauck@decwrl.arpa
DaveMills(Chairman),Linkabitmills@usc-isid.arpa
DennisPerry,DARPA/IPTOperry@ipto.arpa
Thesubcommitteewishestothankthefollowingadditional
contributorsandinvitedreferees:
LenBosack,StanfordU/CISCObosack@su-score.arpa
BobBraden,ISIbraden@isi-braden.arpa
Hans-WernerBraun,UMichiganhwb@gw.umich.edu
NoelChiappa,MIT/Proteonjnc@proteon.arpa
DougComer,PurdueUdec@cs.purdue.edu
IraFuchs,PrincetonUfuchs%pucc.bitnet@wiscvm.wisc.edu
EdKrol,UIllinoiskrol%uiucvmd.bitnet@wiscvm.wisc.edu
BarryLeiner,RIACSleiner@riacs.arpa
MikeMuuss,BRLmike@brl.arpa
RonNatalie,BRLron@brl.arpa
HarveyNewman,CITnewman@cit-hex.arpa
JonPostel,ISIpostel@usc-isib.arpa
MarshallRose,NRTCmrose@nrtc-
JeffSchiller,MITjis@bitsy.mit.edu
LixiaZhang,MITlixia@xx.lcs.mit.edu
1.Introduction
Thefollowingsectionsareintendedasanintroductionandbackground
forthoseunfamiliarwiththeDARPAInternetarchitectureandthe
Internetgatewaymodel.Generalbackgroundanddiscussiononthe
Internetarchitectureandsupportingprotocolsuitecanbefoundin
theDDNProtocolHandbook[25]andARPANETInformationBrochure[26],
bothavailablefromtheNetworkInformationCenter,SRI
International,MenloPark,CA94025.Readersfamiliarwiththese
conceptscanproceeddirectlytoSection2.
1.1.TheDARPAInternetArchitecture
TheDARPAInternetsystemconsistsofanumberofgatewaysand
networksthatcollectivelyprovidepackettransportforhosts
subscribingtotheDARPAInternetprotocolarchitecture.These
protocolsincludetheInternetProtocol(IP),InternetControl
MessageProtocol(ICMP),TransmissionControlProtocol(TCP)and
applicationprotocolsdependinguponthem.AllprotocolsuseIP
asthebasicpacket-transportmechanism.IPisadatagram,or
connectionless,serviceandincludesprovisionforservice
specification,fragmentation/reassemblyandsecurityinformation.
ICMPisconsideredanintegralpartofIP,althoughitis
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RequirementsforInternetGateways--DRAFT
architecturallylayereduponit.ICMPprovideserrorreporting,
flowcontrolandfirst-hopgatewayredirection.Reliabledata
deliveryisprovidedintheprotocolsuitebyTCP,whichprovides
end-endretransmission,resequencingandconnectioncontrol.
ConnectionlessserviceisprovidedbytheUserDatagramProtocol
(UDP).
TheInternetcommunitypresentlyincludesseveralthousandhosts
connectedtoover400networkswithabout120gateways.Thereare
nowwellover2400hostsregisteredintheARPAdomainaloneand
anunknownnumberregisteredinotherdomains,withthetotal
increasingatabouttenpercenteachmonth.Manyofthehosts,
gatewaysandnetworksintheInternetcommunityareadministered
bycivilorganizations,includinguniversities,research
laboratoriesandequipmentmanufacturers.Mostoftheremainder
areadministeredbytheUSDoDandconsideredpartoftheDDN
Internet,whichpresentlyconsistsofthreesetsofnetworks:
the
experimentalsegment,orARPANET,theunclassifiedsegment,or
MILNET,andtheclassifiedsegment,whichdoesnotyethavea
collectivename.
TheInternetmodelincludesconstituentnetworks,calledlocal
networkstodistinguishthemfromtheInternetsystemasawhole,
whicharerequiredonlytoprovidedatagram(connectionless)
transport.Thisrequiresonlybest-effortdeliveryofindividual
packets,ordatagrams.Eachdatagramcarries32-bitsourceand
destinationaddresses,whichareencodedinthreeformats
providingatwo-partaddress,oneofwhichisthelocal-network
numberandtheotherthehostnumberonthatlocalnet.According
totheInternetservicespecification,datagramscanbedelivered
outoforder,belostorduplicatedand/orcontainerrors.In
thosenetworksprovidingconnection-orientedservicetheextra
reliabilityprovidedbyvirtualcircuitsenhancestheend-end
robustnessofthesystem,butisnotstrictlynecessary.
LocalnetworksareconnectedtogetherintheInternetmodelby
meansofInternetgateways.Thesegatewaysprovidedatagram
transportonlyandnormallyseektominimizethestateinformation
necessarytosustainthisserviceintheinterestofrouting
flexibilityandrobustness.Intheconventionalmodelthegateway
hasaphysicalinterfaceandaddressoneachofthelocalnets
betweenwhichitprovidesforwardingservices.Thegatewayalso
participatesinoneormoredistributedroutingorreachability
algorithmsuchastheGateway-GatewayProtocol(GGP)orExterior
GatewayProtocol(EGP)inordertomaintainitsroutingtables.
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RequirementsforInternetGateways--DRAFT
1.2.TheInternetGatewayModel
AnInternetgatewayisaself-contained,stand-alonepacketswitch
thatperformsthefollowingfunctions:
1.Interfacestotwoormorepacket-switchingnetworks,
includingencapsulation,addresstransformationandflow
control.
2.ConformstospecificDARPAInternetprotocolsspecifiedin
thisdocument,includingtheInternetProtocol(IP),
InternetControlMessageProtocol(ICMP),ExteriorGateway
Protocol(EGP)andothersasnecessary.
3.Supportsaninteriorgatewayprotocol(IGP)reachabilityor
routingalgorithmincasesofmultiplegatewaysoperating
asasystem.SupportstheEGPreachabilityalgorithmto
exchangeroutesbetweensystems,inparticulartheDARPA
"core"systemoperatedbyBBN.
4.ReceivesandforwardsInternetdatagramsconsistentwith
goodengineeringpracticeinthemanagementofresources,
congestioncontrolandfairness.Recognizesvariouserror
conditionsandgeneratesICMPerrorandinformation
messagesasrequired.
5.Providessystemsupportfacilities,includingloading,
debugging,statusreporting,exceptionreportingand
control.
Insomeconfigurationsgatewaysmaybeconnectedto
packet-switchinglocalnetsthatprovidegenericlocal-net
routing,error-controlandresource-managementfunctions.In
othersgatewaysmaybedirectlyconnectedviaseriallines,so
thatthesefunctionsmustbeprovidedbythegatewaysthemselves.
Therearethreetypicalscenariosthatshouldbeaddressedby
gatewayvendors:
1.Nationalorregionalnetwork.Gatewaysofthisclass
shouldbecapableofswitchingmultiplecontinuousflowsin
the1.5-Mbpsrangeatratestoseveralthousandpacketsper
second.Theywillbehigh-performance,possiblyredundant,
multiple-processordevices,probablyprocuredasasystem
andoperatedremotelyfromaregionalornational
monitoringcenter.Thedesignofthesegatewaysshould
emphasizehighaggregatethroughput,throughput-sensitive
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RequirementsforInternetGateways--DRAFT
resourcemanagementandveryhighreliability.Thetypical
applicationwouldbeanNSFbackbonenetoroneofthe
consortiumorregionalnets.
2.Campusnetwork.Gatewaysofthisclassshould
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