Design and Implementation of a Policy-Based Resour

DESIGNANDIMPLEMENTATIONOFAPOLICY-BASEDRESOURCEMANAGEMENTARCHITECTUREParisFlegkas,PanosTrimintzios,GeorgePavlou,AntonioLiottaCentreforCommunicationSystemsResearch,SchoolofElectronics,ComputingandMathematics,UniversityofSurrey,Guildford,SurreyGU27XH,UK,{P.Flegkas,P.Trimintzios,G.Pavlou,A.Liotta}@eim.surrey.ac.uk}Abstract:Policy-basedManagementcanguidethebehaviorofanetworkordistributedsystemthroughhigh-leveldeclarativedirectivesthataredynamicallyintroduced,checkedforconsistency,refinedandevaluated,resultingtypicallyinaseriesoflow-levelactions.Weactuallyviewpoliciesasameansofextendingthefunctionalityofmanagementsystemsdynamically,inconjunctionwithpre-existing“hard-wired”managementlogic.Inthispaper,wefirstdiscussthepolicymanagementaspectsofaresourcemanagementarchitectureforIPDifferentiatedServicesnetworksandwefocusonthefunctionalityofthenetworkdimensioningcomponent.Wethenpresentadetaileddescriptionofthedesignandimplementationofthecomponentsofthepolicymanagementsub-systemneededtobedeployedinordertomakeoursystempolicy-driven.Finally,wepresentexamplesofnetworkdimensioningpoliciesdescribingtheirtransformationfromtheirdefinitionbytheoperatoruntiltheirenforcement.Keywords:Policy-basedManagement,IPDifferentiatedServices,NetworkDimensioning,ResourceManagement1.INTRODUCTIONForyearstheInternetnetworkingcommunityhasbeenstrugglingtodevelopwaystomanagenetworks.Initialattemptsbroughtmechanismsandprotocolsthatfocusedonmanagingandconfiguringindividualnetworkingdevicesi.e.theSimpleNetworkManagementProtocol(SNMP).ThismodelworkedwellinearlyParisFlegkas,PanosTrimintzios,GeorgePavlou,AntonioLiottadeploymentsofIPmanagementsystemsforlocalandmetropolitanareanetworksbutnow,withtheevolutionofQualityofService(QoS)modelssuchastheDifferentiatedServices(DiffServ)framework,thecomplexityandoverheadofoperatingandadministratingnetworksincreasesenormously.Assuch,itisverydifficulttobuildmanagementsystemsthatcancopewiththegrowingnetworksize,complexityandmulti-serviceoperationrequirements.Thereisalsoaneedtobeabletoprogrammanagementsystemsandnetworkcomponentstoadapttoemergingrequirementsandsubsequentlytobeabletodynamicallychangethebehaviorofthewholesystemtosupportmodifiedoradditionalfunctionality.TheemergingPolicy-basedNetworkManagementparadigmclaimstobeasolutiontotheserequirements.Policy-basedManagementhasbeenthesubjectofextensiveresearchoverthelastdecade[1].Policiesareseenasawaytoguidethebehaviorofanetworkordistributedsystemthroughhigh-level,declarativedirectives.TheIETFhasbeeninvestigatingpoliciesasameansformanagingIP-basedmulti-servicenetworks,focusingmoreonthespecificationofprotocols(e.g.COPS)andtheobject-orientedinformationmodelsforrepresentingpolicies.Inconsistenciesinpolicy-basedsystemsarequitelikelysincemanagementlogicisdynamicallybeingadded,changedorremovedwithouttherigidanalysis,design,implementation,testinganddeploymentcycleof“hard-wired”long-termlogic.Conflictdetectionandresolutionisrequiredinordertoavoidorrecoverfromsuchinconsistencies.Inthenextsection,wediscussthepolicymanagementaspectsofaresourcemanagementsystemforIPDifferentiatedServicesnetworks;wethenfocusonthefunctionalityofthedimensioningcomponentinsection3andinsection4,wepresentadetaileddescriptionofthedesignandimplementationofthecomponentsofthepolicymanagementsub-systemneededtobedeployedinordertomakeoursystempolicy-driven.Finally,wepresentexamplesofnetworkdimensioningpolicies,describingtheirtransformationfromtheirdefinitionbytheoperatoruntiltheirenforcement.2.SYSTEMARCHITECTUREWehavedesignedasystemforsupportingQoSinIPDiffServNetworksinthecontextoftheEuropeancollaborativeresearchprojectTEQUILA(TrafficEngineeringforQUalityofserviceintheInternetatLArgescale).ThisarchitecturecanbeseenasadetaileddecompositionoftheconceptofanextendedBandwidthBroker(BB)realizedasahierarchical,logicallyandphysicallydistributedsystem.Adetaileddescriptioncanbefoundin[2].Aclassificationofthepoliciesappliedtothissystemwaspresentedin[3].InFigure1wepresentonlytheresourcemanagementpartofthearchitecturetogetherwiththecomponentsofthepolicymanagementsub-systemi.e.PolicyManagementTool,PolicyRepositoryandPolicyConsumerneededtomakethesystemextensiblethroughpolicies.Design&ImplementationofaPolicy-basedResourceMgmtArchitecture3ROLF\5HSRVLWRU\3ROLF\&RQVXPHU1HWZRUN'LPHQVLRQLQJ!$#&%’!3ROLF\0DQDJHPHQW7RRO’($)+*,,,*-$./’($*1'3ROLFLHV'5W0'5V03ROLFLHV+LJKOHYHO3ROLFLHVPD\UHVXOWLQWKHLQWURGXFWLRQRIUHODWHGSROLFLHVDWORZHUOD\HUVPLUURULQJWKHV\VWHP·VKLHUDUFK\'\QDPLF5HVRXUFH0DQDJHPHQW3ROLF\&RQVXPHU'\QDPLF5RXWH0DQDJHPHQW3ROLF\&RQVXPHU3ROLF\5HSRVLWRU\3ROLF\&RQVXPHU1HWZRUN'LPHQVLRQLQJ3ROLF\&RQVXPHU1HWZRUN'LPHQVLRQLQJ!$#&%’!3ROLF\0DQDJHPHQW7RRO’($)+*,,,*-$./’($*1'3ROLFLHV'5W0'5V03ROLFLHV+LJKOHYHO3ROLFLHVPD\UHVXOWLQWKHLQWURGXFWLRQRIUHODWHGSROLFLHVDWORZHUOD\HUVPLUURULQJWKHV\VWHP·VKLHUDUFK\'\QDPLF5HV