6LoWPAN协议栈中适配层的需求研究(IJWMT-V7-N3-5)

I.J.WirelessandMicrowaveTechnologies,2017,3,49-57PublishedOnlineMay2017inMECS()DOI:10.5815/ijwmt.2017.03.05Availableonlineat*,SanjaySharmaDepartmentofMathematics&ComputerApplicationsMaulanaAzadNationalInstituteofTechnologyM.P.,IndiaAbstractEmergenceofwirelessembeddedapplicationsisresultinginthecommunicationamongsensornodesconnectedinawirelesspersonalareanetwork.Sensornodesgathertherealtimeinformationandtransmitittothedesiredapplication.ThisrequirestransmissionofIPv6packetsoverLow-powerwirelesspersonalareanetworkandiscalled6LoWPAN.IPv6isresourceintensiveprotocolwhereas6LoWPANisresourceconstraintduetosmallpacketsize,limiteddevicememory,shorttransmissionrange,andlessdatarateofsensornodes.Alsothesenodesin6LoWPANaremainlybatteryoperatedhenceminimumpowerconsumptionisalsoamajorconstraint.Tomaketheefficienttransmissionofinformationinsucharesourceconstraintnetwork,anadaptationlayerwassuggestedandimplementedbyInternetEngineeringTaskForce(IETF).TheplacingofthisadditionallayerisinbetweennetworklayeranddatalinklayerofTCP/IPprotocolstack.Thispapercontributesinthedetailedanalysisofneedofadaptationlayerin6LoWPANprotocolstack.Thenecessityofthisadditionallayerisjustifiedbyexplainingthemajorfunctionslikeheadercompression,fragmentationandreassemblyofpacketsandpacketroutinghandledbyit.IndexTerms:6LoWPAN,adaptationlayer,fragmentation,headercompression,meshaddressingheader©2017PublishedbyMECSPublisher.Selectionand/orpeerreviewunderresponsibilityoftheResearchAssociationofModernEducationandComputerScience1.IntroductionDecadesbefore,theadventofInternetandCommunicationTechnology(ICT)hadshrunktheworldbydrasticchangeincommunicationscenarios.Sincethen,theneedofcommunicationisincreasingwhichisnotonlyhumantomachinebutmovingmoretowardsmachinetomachineandmachinetohuman.Plethoraofapplicationsareemergingwhichneedsbillionsofdevicestocommunicatewitheachotherinthephysicalworld.Variousmonitoringsystemslikehealthcare,streetlights,vehicles,agriculturalfields,firedetection,homeautomation,factoryautomation,etc.arejustafewofthemwhichneedslargenumberofsensornodesto*Correspondingauthor.E-mailaddress:[e-mail];[e-mail]50AstudyonNeedofAdaptationLayerin6LoWPANProtocolStackcollecttherealtimeinformationandcommunicateittoalocationwhereneeded.Forcommunicationbetweenthesesensornodes,eachoneofitshouldhaveanIPaddressinthenetwork.WithconstantincreaseinnetworkdevicesandtheirIPaddresses,IPv6addressingisnowdesirableratherthanIPv4astheformercanprovideupto2128uniqueaddresses[1][2].TransmissionofIPv6packetsoverLow-powerwirelesspersonalareanetworkistechnicallyabbreviatedas6LoWPAN[3].TheInternetEngineeringTaskForce(IETF)6LoWPANworkinggroupwasformedin2004.ItsprimepurposeistohandlethechallengesofenablingwirelessIPv6communicationoverthenewlystandardizedIEEE802.15.4low-powerradiofordeviceswithlesstransmissionrange,powerandmemory.Theseresourceconstraintdevicesaremainlysensornodes.2007wastheyearwhenIETFhasfirstreleasedthestandardsandspecificationsof6LoWPAN[4].Thepacketsin6LoWPANhavesmalldatatransmissionrangefrom10mto30mattherateof20kbpsto240kbps,withveryconstraintnodememoryof16kbRAMand128kbROM[5][6].Permissiblepacketsize,shorttransmissionrange,limitedmemory,constraintenergyaresomecompatibilityissuesbetweenIPv6andLoWPAN(IEEEstandard802.15.4).Toremovethesecompatibilityissuesforefficienttransmissionofpackets,anadaptationlayerisplacedbetweennetworkanddatalinklayerofTCP/IPstack.Thispaperemphasizesonthepresenceofthisadditionallayeri.e.adaptationlayerin6LoWPANprotocolstack.Thislayernotonlymanagesthecompatibilityissuesbutalsoreducesthetransmissionoverheadofpacketsas6LoWPANishighlyresourceconstraint.Therestofthepaperisorganizedasfollows:6LoWPANprotocolstackisshowninsection2.Needofadaptationlayerisexplainedinsection3.Section4coversvariousfunctionshandledbyadaptationlayeratsenderandreceivernodes.Conclusionandfutureworkisgiveninsection5.2.6LoWPANProtocolStack6LoWPANhaswirelesssensornodes(WSN)havingIPcommunicationcapabilities.Therearevariousfunctionalincompatibilitiesbetweenthesetwoasexplainedinsection1.Tomakethemcompatiblethereweretwooptions.FirstoptionistomakechangesinexistinglayersofTCP/IPprotocolstack.OtheroptionistoaddanotherlayerinTCP/IPprotocolstackwithoutdisturbingitslayersfunctionalities.ThesecondoptionsuitedwellasitdoesnotaffectexistingTCP/IPlayerarchitecture.Fig.1showstheprotocolstackof6LoWPAN.IthasanadditionallayerascomparetoTCP/IPstack.TheextralayerisAdaptationlayer[3]whoseneedisexplainedinsection3.Fig.1.6LoWPANProtocolStackSimilartoTCP/IPstack,6LoWPANalsohasvariousprotocolstosupportsuccessfulcommunicationbetweennodes[7].Physicallayerprovidesthebasiccommunicationinthenetwork.IttransmitsthedatabitsAstudyonNeedofAdaptationLayerin6LoWPANProtocolStack51over802.15.4byconvertingthemintosignals.ThetaskofDatalinklayeristodetectandcorrecttheerrorswhichmayoccurduringtransmissionofdatabits.MediumaccesslayerorMAClayerispresentindatalinklayer.T