Peer-to-peer мрежа

Мрежови характеристики

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:

Децентрализация

Theresourcesandservicesinthenetworkarescatteredonallnodes,andtheinformationisTherealizationoftransmissionandservicesarecarriedoutdirectlybetweennodes,withouttheinterventionofintermediatelinksandservers,andpossiblebottlenecksareavoided.ThedecentralizedbasiccharacteristicsofP2Pbringitsadvantagesinscalabilityandrobustness.

Мащабируемост

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

Здравина

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

Висока производителност

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

Защита на личните данни

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

Балансиране на натоварването

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

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

Предимства и недостатъци

Предимства

В сравнение с мрежите клиент/сървър, peer-to-peer мрежите имат следните предимства:

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

2.Thenetworkcomposedofpeersiseasytoexpandandmorereliablethanasingleserver.Asingleserverwillbesubjecttoasinglepointoffailure,orwillbecomeabottleneckwhenthenetworkusageishigh.

3.Anetworkcomposedofpeerscanshareprocessorsandintegratecomputingresourcestoperformdistributedcomputingtasks,ratherthanrelyingsolelyonacomputer,suchasasupercomputer.

4.Theusercandirectlyaccessthesharedresourcesonthepeer-to-peercomputer.Thepeersinthenetworkcandirectlysharefilesonthelocalstorageinsteadofsharingonthecentralserver.

недостатъчно

1. Влияят върху производителността на компютъра на потребителя

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

2. Лоша мрежова сигурност

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

3. Трудности при архивиране и възстановяване на ресурси

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

Основен режим

P2Pnetworkismainlybasedontwomostbasicmodes,namelycentralizeddirectorymodeandnon-centralizeddirectorymode.

CentralizedDirectoryMode

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

Режим на нецентрализирана директория

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

Идентификационен метод

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

Стъпки в мрежата

1. Определете топологията на мрежата.

2. Изберете подходяща среда за предаване.

3.Selectnetworkconnectionequipmentaccordingtothetypeoftransmissionmedium,theoperatingspeedofthenetwork,andthecoverageofthenetwork.

4. Хардуерна връзка.

5. Инсталиране и конфигуриране на мрежов софтуер.

6. Настройте споделяне на предварителен източник.

Видове софтуер

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

1. Споделяне и изтегляне на файлово съдържание, като Napster, Gnutella, eDonkey, eMule, Maze, BT и др., потребителите могат директно да изтеглят от Download или да качват файлове на всеки компютър с инсталиран подобен софтуер и да извличат и копират споделени файлове.

2. Компютърна мощност и споделяне на съхранение, като SETI@home, Avaki, PopularPower, Netbatch, Farsite и т.н., могат да се използват за разпространение на обекти за съхранение в мрежата или използване на свободното им време за съвместни изчисления.

3. Платформи за съвместна обработка и споделяне на услуги, базирани на P2P технология, като JXTA, Magi, Groove и др., могат да се използват за управление на предприятието.

4. Инструменти за незабавни съобщения, включително ICQ, QQ, YahooMessenger, MSNMessenger и др., множество потребители могат да комуникират чрез текст, глас или файлове и дори да комуникират с мобилни телефони.

5.P2Pкомуникация и споделяне на информация, като Skype, Crowds, OnionRouting и др.

6. Мрежова телевизия и линейни игри, базирани на P2P технология, като BoilingPoint, PPStream, PPLive, QQLive, SopCast и др.

Технически стандарти

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

Международен

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

Домашни

ДомашниcompanieshavebeenkeepingpacewiththeworldinthefieldofP2Papplicationresearch,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.

Проучване на приложението

P2P разпределена система за съхранение

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

Споделяне на P2P изчислителна мощност

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

Тенденция на развитие

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.