Vertaisverkko

Verkon ominaisuudet

Peer-to-peernetworkisanetworkstructureidea.Anessentialdifferencebetweenitandthecurrentdominantclient/server(Client/Server)structure(thatis,thestructureadoptedbytheWWW)inthecurrentnetworkisthatthereisnocentralnode(orcentralserver)intheentirenetworkstructure.IntheP2Pstructure,eachnode(peer)mostlyhasthreefunctionsatthesametime:informationconsumer,informationprovider,andinformationcommunication.Intermsofcomputingmode,P2PbreaksthetraditionalClient/Server(C/S)mode,andthestatusofeachnodeinthenetworkisequal.Eachnodenotonlyactsasaserver,providesservicesforothernodes,butalsoenjoystheservicesprovidedbyothernodes.

Simplyput,P2Pistoconnectpeopledirectly,allowingpeopletointeractdirectlythroughtheInternet.P2Pmakescommunicationonthenetworkeasier,moredirectsharingandinteraction,andtrulyeliminatesmiddlemen.

AnotherimportantfeatureofP2PistochangethecurrentEthernetstation-centricstateoftheInternet,returnto"decentralization",andreturnpowertousers.

Thepeer-to-peernetworkisasuccessfulexpansionofthedistributedconcept.Itdistributestheburdenoftheserverinthetraditionalwaytoeachnodeinthenetwork,andeachnodewillundertakelimitedstorageandcomputingtasks.Themorenodesthatareaddedtothenetwork,themoreresourcesthenodescontribute,andthehigherthequalityoftheirservices.

Peer-to-peernetworkscanuserelativelypowerfulcomputers(personalcomputers)thatexistattheedgeoftheInternettoperformmoreadvancedtasksthanclient-basedcomputingtasks.ModernPCshaveextremelyfastprocessors,massiveamountsofmemory,andlargeharddrives,andtheycannotfullyexploitthepotentialofthesedeviceswhenperformingroutinecomputingtasks(suchasbrowsinge-mailandtheWeb).ModernPCscaneasilyactasclientsandservers(peers)formanytypesofapplicationsatthesametime.

ThecharacteristicsofP2Pnetworktechnologyarereflectedinthefollowingaspects:

Hajauttaminen

Theresourcesandservicesinthenetworkarescatteredonallnodes,andtheinformationisTherealizationoftransmissionandservicesarecarriedoutdirectlybetweennodes,withouttheinterventionofintermediatelinksandservers,andpossiblebottlenecksareavoided.ThedecentralizedbasiccharacteristicsofP2Pbringitsadvantagesinscalabilityandrobustness.

Skaalautuvuus

InaP2Pnetwork,asusersjoin,notonlydoesthedemandforservicesincrease,buttheoverallsystemresourcesandservicecapabilitiesarealsoexpandingsimultaneously,alwaysItiseasiertomeettheneedsofusers.Intheory,itsscalabilitycanbeconsideredalmostunlimited.Forexample:InthetraditionalwayofdownloadingfilesviaFTP,whendownloadingusersincrease,thedownloadspeedwillbecomeslowerandslower.However,theP2Pnetworkisjusttheopposite.Themoreusersjoin,themoreresourcesareprovidedintheP2Pnetwork.,Thedownloadspeedisfaster.

Vahvuus

P2Parchitectureisinherentlyresistanttoattacksandhighlyfault-tolerant.Sincetheserviceisdistributedamongvariousnodes,thedestructionofsomenodesorthenetworkwillhavelittleimpactonotherparts.P2Pnetworksgenerallycanautomaticallyadjusttheoveralltopologywhensomenodesfailtomaintaintheconnectivityofothernodes.P2Pnetworksareusuallyestablishedinaself-organizingmannerandallownodestojoinandleavefreely.

Korkea kustannustehokkuus

PerformanceadvantageisanimportantreasonwhyP2Piswidelyconcerned.Withthedevelopmentofhardwaretechnology,thecomputingandstoragecapacityofpersonalcomputers,aswellastheperformanceofnetworkbandwidth,haveincreasedrapidlyinaccordancewithMoore'stheorem.AdoptingtheP2ParchitecturecaneffectivelyutilizealargenumberofordinarynodesscatteredontheInternet,anddistributecomputingtasksorstoreddatatoallnodes.Utilizetheidlecomputingpowerorstoragespacetoachievethepurposeofhigh-performancecomputingandmassstorage.Atpresent,theapplicationofP2Pinthisareaismostlyinacademicresearch.Oncethetechnologyismatureandcanbepromotedintheindustrialfield,itcansavemanycompaniesthecostofpurchasinglarge-scaleservers.

Yksityisyydensuoja

InaP2Pnetwork,becausethetransmissionofinformationisdispersedamongnodeswithoutgoingthroughacentralizedlink,theuser’sprivateinformationmaybeeavesdroppedandleakedSexisgreatlyreduced.Inaddition,thecurrentmethodofsolvingInternetprivacyproblemsmainlyadoptsrelayandforwardingtechnology,thushidingcommunicationparticipantsinnumerousnetworkentities.Insometraditionalanonymouscommunicationsystems,therealizationofthismechanismreliesoncertainrelayservernodes.InP2P,allparticipantscanprovidethefunctionofrelaying,whichgreatlyimprovestheflexibilityandreliabilityofanonymouscommunication,andcanprovideuserswithbetterprivacyprotection.

Kuormituksen tasapainoittaminen

IntheP2Pnetworkenvironment,sinceeachnodeisbothaserverandaclient,itreducestherequirementsforthecomputingandstoragecapabilitiesofthetraditionalC/Sstructureserver.Theresourcesaredistributedacrossmultiplenodes,whichbetterrealizestheloadbalanceoftheentirenetwork.

Becausethepeer-to-peernetworkdoesnotrequireadedicatedserverfornetworksupport,andothercomponentsarenotneededtoimprovetheperformanceofthenetwork,thenetworkingcostislow,anditissuitableforscenarioswithfewpersonnelandsimplenetworking.,Soitisoftenusedinsmallandmedium-sizedenterprisesorhomeswithsmallnetworks.

Hyödyt ja haitat

Edut

Verrattuna asiakas-/palvelinverkkoihin, vertaisverkoilla on seuraavat edut:

1Contentandresourcescanbesharedinthecentralandperipheralareasofthenetwork.Inaclient/servernetwork,contentandresourcescanusuallyonlybesharedinthecentralareaof​​thenetwork.

2.Thenetworkcomposedofpeersiseasytoexpandandmorereliablethanasingleserver.Asingleserverwillbesubjecttoasinglepointoffailure,orwillbecomeabottleneckwhenthenetworkusageishigh.

3.Anetworkcomposedofpeerscanshareprocessorsandintegratecomputingresourcestoperformdistributedcomputingtasks,ratherthanrelyingsolelyonacomputer,suchasasupercomputer.

4.Theusercandirectlyaccessthesharedresourcesonthepeer-to-peercomputer.Thepeersinthenetworkcandirectlysharefilesonthelocalstorageinsteadofsharingonthecentralserver.

Riittämätön

1. Vaikuttaa käyttäjän tietokoneen suorituskykyyn

Thecomputerinthepeer-to-peernetworkneedstoundertakeboththeserverandtheworkstationatthesametime,whichmakestheoriginalThesingle-usercomputerofisusedasamulti-usercomputer.Whenlarge-scaledataexchangeiscarriedout,theperformanceofthenetworkwillbegreatlyaffected.

2. Huono verkon turvallisuus

Inapeer-to-peernetwork,resourcesarenotstoredcentrallyinsomecomputers,butarescatteredthroughoutthenetwork,andareManagedbyusers,thereisnoguaranteethatalluserscanprotecttheirresources.Inaddition,themanagementofuseraccountsandpasswordsinapeer-to-peernetworkisalsoanimportantissue.Auserhastomemorizemultiplesetsofaccountsandpasswordstoaccessresourcesindifferentcomputers.

3.Vaikeudet resurssien tukemisessa ja palauttamisessa

Resourcesinpeer-to-peernetworksarerelativelyscattered,anditismorecomplicatedtobackupandrestoreresourcesinallcomputers.Duetotheabovecharacteristics,peer-to-peernetworksaresuitableforoccasionswithfewusers,smallscale,andlowsecurityperformancerequirements.

Päätila

P2Pnetworkismainlybasedontwomostbasicmodes,namelycentralizeddirectorymodeandnon-centralizeddirectorymode.

Keskitetty hakemistotila

Thecentralizeddirectory-basedP2PmodeisalsocalledthestructuredP2Pmode.Inthismode,acentralserverissetuptorecordandmanagethesharedinformationresourcesofallnodes.Eachpeernodequeriestheservertoknowwhichnodeinthepeer-to-peernetworkhasthesharedinformationresourcesitneeds.Afterfindingit,obtainsitshostaddress,andthenfurtherrequeststheinformationresourcesitneedsfromthehost.Finally,thehostwillcopyitssharedinformationandsendittotherequestinghost’scentralizeddirectoryP2Pnetwork.

Ei-keskitetty hakemistomuoto

TheP2Pmodeofnon-centralizeddirectoryisalsocalledpureP2Pmode.Inthenon-centralizedP2Pmodel,thepeer-to-peernetworkdoesnotneedtosetupacentralservertorecordandmanagethesharedinformationresourcesofallnodes.Toobtainasharedinformationresource,anynodefirstaskswhetheritsneighboringnodehastheresource.Ifaneighboringnodedoesnot,itwillfurtheraskitsneighboringnode(theinquirymessagemustIncludingtheaddressoftheinitialrequestingnode),untilthenodewiththeinformationresourcereceivestheinquiryrequest,thenthisnodewillgiveanaffirmativeresponsetotheinitialrequestingnode(andspecifyitsownaddressatthesametime).Finally,theinitialrequestingnodemakesaresourcerequesttothisnode,andthenodecopiesitssharedinformationandsendsittotheinitialrequestingnode.

Tunnistusmenetelmä

CurrentcommunicationmodesincludeClient/Server,Brower/ServerandSlave/Master.Forexample,thecorporateLANIntranetandInternetbothuseClient/ServerandBrowser/Serverasthemodel,whiletheearlyhostsystemadoptstheSlave/Mastermodel.Thecharacteristicsofthesemodesare:theyareallbasedontheapplication,theremustbeanapplicationserverinthenetwork,theuser'srequestmustbecompletedthroughtheapplicationserver,andthecommunicationbetweenusersmustalsogothroughtheserver.Inapeer-to-peernetwork,userscancommunicatedirectly,shareresources,andworktogether.

Verkostoitumisen vaiheet

1.Määritäverkkotopologia.

2.Valitsesopiva lähetysväline.

3.Selectnetworkconnectionequipmentaccordingtothetypeoftransmissionmedium,theoperatingspeedofthenetwork,andthecoverageofthenetwork.

4. Laitteistoliitäntä.

5.Verkkoohjelmiston asennus ja konfigurointi.

6.Aseta resurssien jakaminen.

Ohjelmistotyypit

Currently,P2Pnetworkcomputingtechnologyiscontinuouslybeingappliedtomilitary,commerce,governmentaffairs,telecommunications,communicationsandotherfields.Accordingtodifferentspecificapplications,P2Papplicationsoftwarecanberoughlydividedintothefollowingtypes:

1.Tiedostonsisällön jakaminen ja lataaminen, kuten Napster, Gnutella, eDonkey, eMule, Maze, BT jne., käyttäjät voivat ladata suoraan ladattavasta tai kopioidatiedostosta mistä tahansa tietokoneesta, johon on asennettu samanlainen ohjelmisto, sekä noutaa ja kopioida jaettuja tiedostoja.

2.Voidaan käyttää laskentatehon ja tallennustilan jakamista, kutenSETI@home,Avaki,PopularPower,Netbatch,Farsite jne.,voidaan jakaa tallennusobjekteja verkossa tai käyttää vapaa-aikaansa yhteistyöhön.

3.P2P-teknologiaan perustuvaa yhteiskäsittelyä ja palvelujenjakoalustaa, kuten JXTA, Magi, Groove jne., voidaan käyttää yrityksen hallintaan.

4.Pikaviestintätyökalut, mukaan lukien ICQ, QQ, YahooMessenger, MSNMessenger jne., useat käyttäjät voivat viestiä tekstin, puheen tai tiedostojen kautta ja jopa kommunikoida matkapuhelimien kanssa.

5.P2P-viestintä ja tietojen jakaminen, kuten Skype, Crowds, OnionRouting jne.

6.NetworkTV jaP2P-tekniikkaan perustuvat online-pelit, kuten BoilingPoint, PPStream, PLive, QQLive, SopCast jne. Monet nykyiset verkkopelit ovat myös toteutettu vertaisverkkojen kautta.

Tekniset standardit

Inrecentyears,withtherapidspreadofP2Ptechnology-basedfilesharingsoftwaresuchasNapster,KaZaa,BT,andeMuleontheInternet,P2Ptechnologyhasbeentriggeredbothathomeandabroad.Anewwaveofresearch.

Kansainvälinen

Currently,thereisnouniformstandardforinternationalpeer-to-peernetworks.AP2PworkinggroupwasestablishedinAugust2000,withmembersincludingIntel,IBM,andHP.Othermajorobstaclestothedevelopmentofpeer-to-peernetworksincludecopyrightissues,networkbandwidthissues,managementissues,andsecurityissues.Howtoconnectphones,mobilephonesandhomeappliances,industrialequipment,etc.,isalsoaproblemthatneedstobesolvedinpeer-to-peernetworks.

Kotimainen

KotimainencompanieshavebeenkeepingpacewiththeworldinthefieldofP2Papplicationresearch,andhavedevelopedmanywidelyusedP2Pproducts.Theseproductsaremainlyconcentratedinfilesharinganddownloading,networkstreamingTVandsoon.

• POCO

POCOisChina’sleadingfreemovie,music,animationandothermultimediasharingplatform,andthenumberofpeopleonlineatthesametimeexceedsthenumberWith700,000people,itisChina'slargestmovie,music,andanimationsharingplatform.Itisathird-generationP2Presourceexchangeplatformwithflowcontrolandnocentralserver.POCOprovidestechnologiessuchasmulti-pointtransmissionandresumabletransmissiontoensuretheefficiencyandstabilityofthetransmissionprocess.

• OP

Tothemusic,movies,software,games,pictures,booksandvariousdocumentsyouwant,Thefilecapacityofhundredsofmillionsoffilescanbesharedonlineatanytime.OPintegratesInternetExplorer,WindowsMediaPlayer,RealOnePlayerandACDSee,andisadomesticonlineentertainmentcontentplatform.

• PPLive

PPLiveisasharingsoftwareforlarge-scalelivevideostreamingontheInternet.Itusesthemeshmodeltoeffectivelysolvethebandwidthandloadlimitationofthecurrentnetworkvideo-on-demandservice.Themoreusers,thesmoothertheplayback,andtheoverallservicequalityisgreatlyimproved.

Sovellustutkimus

P2P-jaettu tallennusjärjestelmä

P2P-jaettu tallennusjärjestelmä(filesharinganddownloading)isadatastoragesystemforpeer-to-peernetworks,Itcanprovideefficient,robustandload-balancedfileaccessfunctions.Forstoragesystems,userscareabouttheefficiencyofdatalocation,search,androuting,andsecurityisalsoanimportantfactor.Inmanycases,thecentralizedmethodisnolongersuitableforthislarge-scaledatastoragerequirement,whichrequiresanewsystemtomanagethedatainthesystem.P2P-jaettu tallennusjärjestelmäistosolvesuchproblems.Thesestudiesincludefullydistributedstoragesystems:Oceanstore,PastandFreeHaven,etc.Amongthem,semi-distributedP2Papplicationsbasedonthesuper-pointstructuresuchasKaZaa,Edonkey,Morpheus,BitTorrent,etc.alsobelongtothecategoryofP2Psharedstorage,andthenumberofusershasincreasedsharply.BothOceanstoreandPastprovideaneffectiveWANstoragemodel.TheirbottomlayerhasestablishedaroutingstrategywithacostupperlimitoflogN.Pastisorientedtoarelativelysimpleandcompactconcept.ItusestheroutingmechanismprovidedbyPastrytotrytouseidlestoragenodesinthenetworktoestablishamorecompletestoragesemantics.FreeHavenhasestablishedadetailedanonymitysystemtopreventpotentialmaliciousattacks.

P2P-laskentatehon jakaminen

Inadditiontosharingstoragecapabilities,nodesthatjoinapeer-to-peernetworkcanalsoshareCPUprocessingcapabilities.Therearealreadysomecomputingpowersharingsystemsbasedonpeer-to-peernetworks,suchasSETI@home.SETI@homeisaresearchprojectcarriedoutbytheUniversityofCalifornia,Berkeleytofindalienlife.ItusesP2Ptechnologytoconnectallidlecomputersparticipatingintheresearchprojecttoperformcomplexcalculationstoanalyzeradiosignalsfromplanetsandfindevidencethatotheraliencivilizationsmayexistintheuniverse.Theaveragedailyperformanceofthesecomputersexceedsthehighestcostintheworld.,Thefastestsupercomputer.Thiscomputingpowersharingsystemcanalsobeusedforapplicationsthatrequirelarge-scalecomputingpower,suchasgeneticdatabaseretrievalandpasswordcracking.

Kehityssuunta

IntermsofP2Pcollaborativecomputing,domesticenterprisesstartedlate.Therearenotmanyrelatedproducts,andforeigncountriessuchasGroovehavedonealotofworkinthisareaanddevelopedrelativelymatureproducts.Withtheriseoftheconceptofcollaborativecomputing,thedemandforsoftwareinthisareaisshowingatrendofrapidgrowth,anditshouldbeavastocean.Moreover,thistypeofsoftwareisoftengearedtowardsenterpriseandgovernmentusers,soithasbetterprofitmarginsthanfreeP2Pfilesharingsoftware.

IntermsofP2Pstreamingmediatechnology,atpresent,theresearchonstreamingmediatransmissionhasjuststarted,andtherearestillmanyproblemstobesolved.SincethebehaviorofnodesintheP2PstreamingmediasystemisofAd-Hocnature,howtoensurethequalityofserviceofstreamingmediainadynamicsystemenvironmentneedstocombinetheknowledgeofstreamingmedia’sQoSrequirementsandnetworktrafficanalysistostudyhighefficiency,Low-costQoSguaranteemechanism.Researchabledirectionsinclude:theselectionofservicenodes,howtoensurethecontinuityofstreamingmediaserviceswhenanodefails,andthetransmissionschedulingofmultiplesenders.

ThegreatsuccessofSkype,aVoIPproductbasedonP2Ptechnology,hasopenedupanothernewfieldforP2P.RelevantexpertsbelievethatthereshouldbetworoadsforthedevelopmentofVOIP.Oneistherouteoftraditionaltelecomoperators,namely,theestablishmentofanIMSplatformonamanageableIPnetworktodevelopVoIPvoiceservices.Thiskindofnetworkisclosedandmanageable.TheotherisapublicP2PVoIPnetworkbasedontheexistingInternetpublic.Itischaracterizedbyopenness,anyonecanfreelyjoinandleavethenetwork,hasdistributedmanagementandgrowthcapabilities,andanydevicecanbeusedaslongasitsupportsstandardprotocols.Theinterestneedsoftraditionaltelecomoperatorsandtheneedsofusershavebecomeacontradiction,buttheneedsofthemarketandthedevelopmenttrendofVOIPcannotbechanged.Itisstilluncertainwhichpathwillbeadoptedinthefuture.Itdependsondevelopmentandcompetition.TheremaybemanylargecorporatecustomersandgovernmentagenciesthathavespecialrequirementsforsecurityandwilluseVOIPservicesestablishedbytelecomoperators.However,forordinaryusers,P2PVoIPnetworksbasedonthepublicInternetwillbethegeneraltrend.

Tosumup,P2Ptechnologyisinthespringofdevelopment.Killerapplicationsbasedonthistechnologywillcontinuetoemerge.ThesetechnologieswillgreatlyimprovetheappearanceoftheentireITworld,whichcanbesaidtobetheInternet.Anothernewrevolutionintechnology.