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QoS and Video DeliveryInternet QoS: A Big Picture[1][2][3][4]IntroductionInteServ and RSVPSlide 5Slide 6Slide 7Slide 8Slide 9DiffServSlide 11Slide 12Slide 13Slide 14Slide 15Slide 16MPLSSlide 18Slide 19Traffic Engineering and Constraint-Based RoutingTraffic EngineeringConstraint-Based RoutingUser-Oriented QoS in Packet Video Delivery[5]User-Oriented QoS in Packet Video DeliverySlide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Dynamic Quality of Service Framework for Video in Broadband Networks[6]Dynamic Quality of Service Framework for Video in Broadband NetworksSlide 36Slide 37Slide 38QoS-Sensitive Flows[7]A Management and Control Architecture for Providing IP Differentiated Services in MPLS-Based Networks[8]A Management and Control Architecture for Providing IP Differentiated Services in MPLS-Based NetworksSlide 42ConclusionsReferencesSlide 45QoS and Video DeliveryPresented by Wei WeiInternet QoS: A Big Picture[1][2][3][4]•Current Internet approachBest effortNo guarantees•Need of providing QoS for video applicationsIntroduction•Integrated Services (InteServ) and Resource Reservation Protocol (RSVP)•Differentiated Service (DiffServ)•Multiprotocol Label Switching (MPLS)•Traffic Engineering and Constraint Based RoutingInteServ and RSVP•Philosophy BehindRouters have to be able to reserve resources to provide special QoS for specific user packet streams•Four components of IntServ ModelThe signaling protocol (e.g. RSVP)The admission control routineThe classifierThe packet schedulerInteServ and RSVP•How RSVP works?InteServ and RSVP•Sender sends a PATH Message to the receiver specifying the characteristics of the trafficEvery intermediate router along the path forwards the PATH Message to the next hop determined by the routing protocol•The receiver responds with a RESV Message to request resources for the flowInteServ and RSVP•Every intermediate router along the path can reject or accept the request of the RESV MessageRejected, the router send an error message to the receiver, the signaling process will terminate  Accepted, Resources (link bandwidth and buffer space) are allocated for the flow and the related flow state information will be installed in the routerInteServ and RSVP•Admission controlDecide whether a request for resources can be granted•ClassifierWhen a router receives a packet, the classifier will perform a Multi-Field (MF) classification and put the packet in a specific queue based on the classification result•Packet schedulerSchedule the packet accordingly to meet its QoS requirementsInteServ and RSVP•Problems– Not scalable•Huge storage and processing overhead on the routers•The amount of state information increases proportionally with the number of flows–Requirement on routers is high•All routers must implement RSVP, admission control, MF classification, and packet schedulingDiffServ•Main Idea–Push all complex functions to the edge routers•Edge routers are responsible for multi-field classification and translating that into a DSCP•Core routers treat packets through DS field–Marking the DS fields of packets differently, then handling packets based on their DS fieldsDiffServ•ArchitectureDiffServ•Architecture–Ingress routers •Police/shape traffic•Set Differentiated Service Code Point (DSCP) in Diffserv (DS) field–Core routers•Implement Per Hop Behavior (PHB) for each DSCP•Process packets based on DSCPDiffServ•Two types of service–Assured service–Premium service•Plus, best-effort serviceDiffServ•Assured Service–Defined in terms of user profile, how much assured traffic is a user allowed to inject into the network–Network: provides a lower loss rate than best-effort•In case of congestion best-effort packets are dropped first–User: sends no more assured traffic than its profile•If it sends more, the excess traffic is converted to best-effortDiffServ•Premium service–Provides the abstraction of a virtual pipe between an ingress and an egress router–Network: guarantees that premium packets are not dropped and they experience low delay–User: does not send more than the size of the pipe•If it sends more, excess traffic is delayed, and dropped when buffer overflowsDiffServ•Advantage–Scalable•Edge routers maintain per aggregate state•Core routers maintain state only for a few traffic classes–Easy implementation•Incremental deployment is possible for Assured Forwarding•Disadvantage–Provide weaker service than InteServMPLS•Label Switching–Header of the packet contains a label that is used to advance the packet toward its destination–The label simplifies the forwarding decision a node must make for the packet•A group of packets forwarded in the same manner are said to belong to the same Forwarding Equivalence Class (FEC)MPLS•Label Switched Paths (LSPs)–Within an MPLS domain, a path is set up for a given packet to travel based on a Forwarding Equivalence Class (FEC)–The LSP is set up prior to data transmissionMPLS•MPLS improves packet forwarding performance–Enhances and simplifies packet forwarding through routers that use layer-2 switching–Simplicity allows for easy implementation•MPLS supports QoS for service differentiation– Use traffic-engineered path set-up and support QoS guarantees–Classification and QoS service are determined by the labelsTraffic Engineering and Constraint-Based Routing•Traffic Engineering is the process of arranging how traffic flows through the network so that congestion caused by uneven network utilization can be avoided•Constraint-Based Routing is used to compute routes that are subject to multiple constraints.Traffic Engineering•Network congestion can be caused by lack of network resources or by uneven distribution of traffic–In the first case, all routers and links are overloaded and the only solution is to provide more resources by upgrading the infrastructure–In the second case, uneven traffic distribution can be caused by the current Dynamic Routing protocols such as RIP and OSPF, because they always select the shortest paths to forward packets–Traffic Engineering can be utilized to avoid congestion or to provide graceful degradation in case of congestionConstraint-Based Routing•Constraint-Based Routing with DiffServ–Select routes for flows so that their QoS requirements are most likely to be met•Constraint-Based Routing with RSVP–Select the path for RSVP


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Berkeley ELENG 290T - QoS and Video Delivery

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