MPLS and GMPLSOutlinePart I: MPLSWhy MPLS?Basic IdeaBasic Idea (Cont.)MPLS OperationMain featuresPart II: GMPLSSlide 10GMPLSWhy GMPLS?Why GMPLS? (Cont.)Slide 14GMPLS and MPLSControl interfacesChallengesSuggested labelBi-Directional LSP setupLink Management ProtocolGMPLS SummaryPart III: The Reality CheckQuestion: Will MPLS replace ATM?Opinion 1:Opinion 1 (Cont.)Slide 26Opinion 2GMPLS QuestionsSummaryMPLS and GMPLSLi YinCS294 presentationOutlinePart I: MPLS Part II: GMPLSPart III: The reality checkPart I: MPLSWhy MPLS?MPLS stands for: “Multi-Protocol Label Switching”Goals:–Bring the speed of layer 2 switching to layer 3•May no longer perceived as the main benefit: Layer 3 switches–Resolve the problems of IP over ATM, in particular:•Complexity of control and management•Scalability issues–Support multiple layer 2 technologiesBasic IdeaMPLS is a hybrid model adopted by IETF to incorporate best properties in both packet routing & circuit switchingForwarding:Label SwappingControl:IP Router SoftwareControl:IP Router SoftwareForwarding:Longest-match LookupControl:ATM Forum SoftwareForwarding:Label SwappingIP RouterMPLSATM SwitchBasic Idea (Cont.)Packets are switched, not routed, based on labelsLabels are filled in the packet headerBasic operation:–Ingress LER (Label Edge Router) pushes a label in front of the IP header–LSR (Label Switch Router) does label swapping–Egress LER removes the label The key : establish the forwarding table–Link state routing protocols•Exchange network topology information for path selection•OSPF-TE, IS-IS-TE–Signaling/Label distribution protocols:•Set up LSPs (Label Switched Path)•LDP, RSVP-TE, CR-LDPMPLS Operation1a. Routing protocols (e.g. OSPF-TE, IS-IS-TE) exchange reachability to destination networks1b. Label Distribution Protocol (LDP) establishes label mappings to destination network2. Ingress LER receives packet and “label”s packetsIPIP103. LSR forwards packets using label swappingIP20IP404. LER at egress removes label and delivers packetIPMain featuresLabel swapping:–Bring the speed of layer 2 switching to layer 3Separation of forwarding plane and control planeForwarding hierarchy via Label stacking–Increase the scalabilityConstraint-based routing–Traffic Engineering–Fast rerouteFacilitate the virtual private networks (VPNs)Provide class of service–Provides an opportunity for mapping DiffServ fields onto an MPLS labelFacilitate the elimination of multiple layersPart II: GMPLSOutlineWhy GMPLS?GMPLS and MPLSControl interfacesChallenges of GMPLSSeveral proposed techniques–Suggested label–Bi-direction LSP setup–LMPSummaryGMPLSGMPLS stands for “Generalized Multi-Protocol Label Switching”A previous version is “Multi-Protocol Lambda Switching”Developed from MPLSA suite of protocols that provides common control to packet, TDM, and wavelength services. Currently, in development by the IETFWhy GMPLS?GMPLS is proposed as the signaling protocol for optical networksWhat service providers want?•Carry a large volume of traffic in a cost-effective way•Turns out to be a challenge within current data network architecture•Problems:–Complexity in management of multiple layers –Inefficient bandwidth usage–Not scalable• Solutions: eliminate middle layers IP/WDM Need a protocol to perform functions of middle layersIPATMSONET/SDHDWDMCarry applications and servicesTraffic EngineeringTransport/ProtectionCapacityWhy GMPLS? (Cont.)Optical ArchitecturesA control protocol support both overlay model and peer model will bring big flexibility–The selection of architecture can be based on business decision Peer ModelOverlay ModelUNIUNIWhy GMPLS? (Cont.)What we need? A common control plane–Support multiple types of traffic (ATM, IP, SONET and etc.)–Support both peer and overlay models–Support multi-vendors–Perform fast provisioningWhy MPLS is selected? –Provisioning and traffic engineering capabilityGMPLS and MPLSGMPLS is deployed from MPLS–Apply MPLS control plane techniques to optical switches and IP routing algorithms to manage lightpaths in an optical networkGMPLS made some modifications on MPLS–Separation of signaling and data channel–Support more types of control interface–Other enhancementControl interfacesExtend the MPLS to support more interfaces other than packet switch–Packet Switch Capable (PSC)• Router/ATM Switch/Frame Reply Switch–Time Division Multiplexing Capable (TDMC)•SONET/SDH ADM/Digital Crossconnects–Lambda Switch Capable (LSC)•All Optical ADM or Optical Crossconnects (OXC)–Fiber-Switch Capable (FSC)LSPs of different interfaces can be nested inside anotherFSCLSCLSCTDMCTDMCPSCChallengesRouting challenges–Limited number of labels–Very large number of links•Link identification will be a big problem•Scalability of the Link state protocol •Port connection detectionSignaling challenges–Long label setup time–Bi-directional LSPs setupManagement challenges–Failure detection–Failure protection and restorationSuggested labelProblem: it takes time for the optical switch to program switch –Long setup timeSolution:–Each LSR selects a label (Suggested Label) and signals this label to downstream LSR, and start program its switch.reduce LSP setup overheadSuggested Label = Program Switch XSuggested Label = Reserved Label = Reserved Label = Make sure the programming request has completedRequestProgram Switch XRequestMap Label = Map Label = No suggested labelwith suggested labelBi-Directional LSP setupProblem: How to set up bi-directional LSP?Solution:–Set up 2 uni-directional LSP•Signaling overhead•End points coordination–One single message exchange for one bi-directional LSP•Upstream Label. Suggested Label = Upstream Label = aSuggested Label = Upstream Label = bReserved Label = Reserved Label = abLink Management Protocol Problem:–How to localize the precise location of a fault? –How to validate the connectivity between adjacent nodes?Solution: link management protocol–Control Channel Management–Link Connectivity Verification –Link Property Correlation –Fault Management –AuthenticationGMPLS SummaryProvides a new way of managing network resources and
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