Rete peer-to-peer

Networkcharacteristics

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:

Decentralisation

Theresourcesandservicesinthenetworkarescatteredonallnodes,andtheinformationisTherealizationoftransmissionandservicesarecarriedoutdirectlybetweennodes,withouttheinterventionofintermediatelinksandservers,andpossiblebottlenecksareavoided.ThedecentralizedbasiccharacteristicsofP2Pbringitsadvantagesinscalabilityandrobustness.

Scalability

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

Roburness

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

Highcostperformance

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

Privacyprotection

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

Loadbalancing

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

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

Incommodorum

commoda

Comparatus/servernetworks, pares ut-peernetworks habent sequentia commoda:

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

2.Thenetworkcomposedofpeersiseasytoexpandandmorereliablethanasingleserver.Asingleserverwillbesubjecttoasinglepointoffailure,orwillbecomeabottleneckwhenthenetworkusageishigh.

3.Anetworkcomposedofpeerscanshareprocessorsandintegratecomputingresourcestoperformdistributedcomputingtasks,ratherthanrelyingsolelyonacomputer,suchasasupercomputer.

4.Theusercandirectlyaccessthesharedresourcesonthepeer-to-peercomputer.Thepeersinthenetworkcandirectlysharefilesonthelocalstorageinsteadofsharingonthecentralserver.

insufficiens

1.Affect the forma-computarii usoris

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

2.Poornetworksecurity

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

3.Difficultiesinbackingupandrestoringresources

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

Mainmode

P2Pnetworkismainlybasedontwomostbasicmodes,namelycentralizeddirectorymodeandnon-centralizeddirectorymode.

CentralizedDirectoryMode

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

Non centralizeddirectorymode

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

Identificationmethod

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

Networkingsteps

1.Determinethenetworktopology.

2.Chooseasuitabletransmissionmedium.

3.Selectnetworkconnectionequipmentaccordingtothetypeoftransmissionmedium,theoperatingspeedofthenetwork,andthecoverageofthenetwork.

4.Hardwareconnection.

5. Installation andconfiguration of networksoftware.

6.Setupresourcesharing.

Typesofsoftware

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

1.Filecontentsharing anddownloading, suchasNapster,Gnutella,eDonkey,eMule,Maze,BT,etc.,userscandirectlydownload fromDownloadoruploadfilesonanyPC withsimilarsoftwareinstalled, andretrieveandcopysharedfiles.

2. Computing power andstoragesharing, suchasSETI@domum,Avaki,Popularem,Netbatch, Farsite, etc.

3. Collaborativa processus et operandi communicatio plasmationis P2Ptechnologiae, ut JXTA, Magi, Sulcus, etc., in usu esse potest.

4. Instantmessaging instrumenta, inter ICQ, QQ, YahooMessenger, MSNMessenger, etc., multiplei usuarii possunt communicare per textum, vocem orfiles, et etiam communicare cum mobile phones.

5.P2Pcommunicationi et informationis communicandi, ut Skype, Turbae, OnionRouting, etc.

6.NetworkTVandonlinegamesbasedonP2Ptechnologiae,utBoilingPoint,PPStream,PPLive,QQLive,SopCast,etc. Multae venae inlineae sunt etiam implemented per pares operas.

Technicalstandards

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

International

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

Domestic

DomesticcompanieshavebeenkeepingpacewiththeworldinthefieldofP2Papplicationresearch,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.OP*integratesInternetExplorer,WindowsMediaPlayer,RealOnePlayerandACDSee,andisadomesticonlineentertainmentcontentplatform.

• PPLive

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

Applicationresearch

P2Pdistributedstoragesystem

P2Pdistributedstoragesystem(filesharinganddownloading)isadatastoragesystemforpeer-to-peernetworks,Itcanprovideefficient,robustandload-balancedfileaccessfunctions.Forstoragesystems,userscareabouttheefficiencyofdatalocation,search,androuting,andsecurityisalsoanimportantfactor.Inmanycases,thecentralizedmethodisnolongersuitableforthislarge-scaledatastoragerequirement,whichrequiresanewsystemtomanagethedatainthesystem.P2Pdistributedstoragesystemistosolvesuchproblems.Thesestudiesincludefullydistributedstoragesystems:Oceanstore,PastandFreeHaven,etc.Amongthem,semi-distributedP2Papplicationsbasedonthesuper-pointstructuresuchasKaZaa,Edonkey,Morpheus,BitTorrent,etc.alsobelongtothecategoryofP2Psharedstorage,andthenumberofusershasincreasedsharply.BothOceanstoreandPastprovideaneffectiveWANstoragemodel.TheirbottomlayerhasestablishedaroutingstrategywithacostupperlimitoflogN.Pastisorientedtoarelativelysimpleandcompactconcept.ItusestheroutingmechanismprovidedbyPastrytotrytouseidlestoragenodesinthenetworktoestablishamorecompletestoragesemantics.FreeHavenhasestablishedadetailedanonymitysystemtopreventpotentialmaliciousattacks.

SharingofP2Pcomputingpower

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

Developmenttrend

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.