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QoS ( Intserv & Diffserv)QoSWhat is IntservInterservFramework of IS ModelRSVPProcessing and Propagation of Path Messages by Network RoutersSlide 8RSVP FiltersFactors Impeding Deployment of Intserv/RSVPWhat is DiffservSlide 12TerminologySlide 14Slide 15SLALogical View of Packet Classifier and Traffic ConditionerSlide 18Slide 19Service TaxonomyAssured Forwarding (AF) ClassExpedited Forwarding (EF) ClassWorking within a DomainSlide 24Slide 25Intra-Domain Resource Allocation ArchitectureEdge Router-BB CommunicationSlide 28Interdomain CommunicationFunctions of BBSteps in Interdomain CommunicationSlide 32Slide 33Multicasting in DS DomainNRSNRS cont.Slide 37Heterogeneous Multicasting GroupsDynamics of Arbitrary Sender ChangeSecurity Consideration2 Bit Differentiated Services Architecture for the InternetBlock Diagram of First Hop Router Input FunctionalityMarkers to Implement the 2 Different ServicesBorder Router Input Interface Profile MetersRouter Output Interface for 2-bit ArchitectureStatically Configured Example with no BB Messages ExchangedEnd-to-End Example with Static AllocationEnd-to-End Static Allocation eg. with no Remaining AllocationFirst Step in End-to-End Dynamic Allocation ExampleSecond Step in End-to-End Dynamic Allocation ExampleThird Step in End-to-End Dynamic Allocation ExampleFourth Step in End-to-End Dynamic Allocation ExampleFinal Step in End-to-End Dynamic Allocation ExampleIntserv Operation over DiffservSlide 55Statically Provisioned Diffserv Network RegionRSVP -Aware Diffserv Network RegionComparison of Intserv & Diffserv ArchitecturesSlide 59QoS ( Intserv & Diffserv)BYANJALI KULKARNIYI-AN CHENQoS •Current Internet offers best effort service only•As the Internet is the ubiquitous communications infrastructure, there is a clear need for providing differentiated classes of service to network trafficWhat is Intserv•Service differentiation in the Internet•Focuses on individual packet flows•Each flow requests specific levels of service from network•Levels of service quantified as a minimum service rate, or a maximum tolerable end-to-end delay or loss rate•Network grants or rejects the flow requests, based on availability of resources and the guarantees provided to other flowsInterserv•Best effort service•Real time service•Controlled link sharingMulti-entity link-sharingMulti-protocol link-sharingMulti-service sharingFramework of IS Model•Packet scheduler•Admission control•Classifier•Reservation setup protocol(RSVP)RSVP•Path messages•Resv messages•PathErr, PathTear, ResvErr, ResvTear, ResvConf MessagesPhop, Sender template, Tspec, AdspecReservation style, Filter specification, Rspec, TspecProcessing and Propagation of Path Messages by Network Routers•Update the path state entry•Set cleanup timer•Create and forward Path messageAny change to stored path state or a change in the set of outgoing interfaces in the data forwarding pathEvery refresh period timeout intervalRSVPAppli-cationRSVPproc.Polcyctrlclass-ifierPacketSchedulerAdmissionctrlClassifierpacketscheduleradmissionctrl.RoutingProcessRSVPPocessPolcyctrl.DataRSVP RSVPDataDataRouterHostRSVP FiltersSender Selection Distinct Shared Explicit Fixed-Filter (FF) Style Share-Explicit (SE) Style Wildcard None Defined Wildcard-Filter (WF) StyleFactors Impeding Deployment of Intserv/RSVP•Use of per-flow state and per-flow processing raises scalability concerns for large network•The necessary policy control mechanisms have only recently become availableWhat is Diffserv•Based on a model where traffic entering a network is classified , possibly conditioned at the boundaries of the network, and assigned to different service classes•Here, we avoid complexity and maintenance of per-flow state information in core nodes and push unavoidable complexity to the network edgesWhat is Diffserv•Provide scalable service differentiated in the internet that can be used to permit differentiated pricing of internet service•Separate packet forwarding model from routing modelTerminology•Per Hop Behavior(PHB)•DS Domain( e.g. ISP, intranet)•DS Boundary Node(Egress & Ingress)•DS Interior Node•DS Codepoint(DSCP)•DS Behavior AggregateTerminology•Bandwidth Broker (BB)Logical entity, can be mapped to a single or multiple physical entityA logical entity residing in each administrative domain managing internal demands & resources according to some policy database (who can do what where and when)Setting up & maintaining bilateral agreement with neighbor domainsTerminology•SLA(SLS) & TCA(TCS)Customer/Provider boundariesService Level Agreement A set of parameters and their values which together define the service offered to a traffic stream by a DS domainTraffic Conditioning Agreement A set of parameters and their values which together specify a set of classifier rules and traffic profileSLALogical View of Packet Classifier and Traffic ConditionerclassifierMeterMarkerShaper/DropperPacketsTerminology•Classifier•Traffic Profile Specifies the temporal properties of a traffic stream selected by a classifier. It provides rules for determining whether a particular packet is in-profile or out-of-profile•BA Classifier•MF ClassifierTerminology•Traffic Conditioner•Meter•Marker•Shaper•Dropper•Host Marking•Router MarkingService Taxonomy•Quantitative Service•Qualitative Service•Relative Quantification ServiceTraffic offered at service level A will be delivered with low latency90% of in profile traffic delivered at service level B will experience of no more than 50 msec latencyTraffic with drop precedence AF12 has a higher probability of delivery than traffic with drop precedence AF13Assured Forwarding (AF) Class•As long as aggregate traffic from some sites connecting to internet does not exceed the subscribed information rate, forward packets with high probability •AF PHB group - Forwarding of IP packets in N independent AF classes. Within each class, an IP packet is assigned M different levels of drop precedence•Queuing and discard behaviorExpedited Forwarding (EF) Class•Providing low loss, low latency, low jitter, assured bandwidth, end-to-end service through DS domains•EF PHB A router uses policing and shaping mechanism to ensure that the maximum arrival rate of a traffic aggregate is less than its minimum departure rateWorking within a DomainBBSourceDest.Edge RouterCore RouterDS DomainWorking within a Domain•Step 1


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UB CSE 620 - QoS ( Intserv and Diffserv)

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