WUSTL CIS 777 - ATM Networks: An Overview - D723704

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WUSTL CIS 777 - ATM Networks: An Overview

School name Washington University in St. Louis

Course Cis 777- Telecommunications Networks

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ATM Networks: An OverviewOverviewATMATM vs Phone NetworksATM vs Data NetworksOld House vs New HouseATM InterfacesSlide 8Protocol LayersSlide 10Cell Header FormatPath vs ChannelsVP/VC Assignment/UseOriginal Classes of TrafficAAL 5AAL2Physical MediaSummaryATM : Key ReferencesRaj Jain1ATM Networks:ATM Networks:An OverviewAn OverviewRaj Jain Professor of Computer and Information SciencesThe Ohio State UniversityColumbus, OH 43210-1277These slides are available athttp://www.cse.ohio-state.edu/~jain/cis777-99Raj Jain2ATM vs Phone Networks and Data NetworksATM Protocol LayersCell Header Format, AALs Physical Media Traffic Management: ABR, UBR, GFROverviewOverviewRaj Jain3ATMATMATM Net = Data Net + Phone NetCombination of Internet method of communication (packet switching) and phone companies’ method (circuit switching)ATMRaj Jain4ATM vs Phone NetworksATM vs Phone NetworksCurrent phone networks are synchronous (periodic). ATM = Asynchronous Transfer ModePhone networks use circuit switching. ATM networks use “Packet” SwitchingIn phone networks, all rates are multiple of 8 kbps.With ATM service, you can get any rate.You can vary your rate with time.With current phone networks, all high speed circuits are manually setup. ATM allows dialing any speed.125 sRaj Jain5ATM vs Data NetworksATM vs Data NetworksSignaling: Internet Protocol (IP) is connectionless.You cannot reserve bandwidth in advance.ATM is connection-oriented. You declare your needs before using the network.PNNI: Path based on quality of service (QoS)Switching: In IP, each packet is addressed and processed individually. Traffic Management: Loss based in IP.ATM has 1996 traffic management technology.Required for high-speed and variable demands.Cells: Fixed size or small size is not importantRaj Jain6Old House vs New HouseOld House vs New HouseNew needs:Solution 1: Fix the old house (cheaper initially)Solution 2: Buy a new house (pays off over a long run)Raj Jain7PrivateNNIPrivateUNIATM InterfacesATM InterfacesComputerPrivateSwitchPublicSwitchRouterDigitalServiceUnitDXIB-ICIPublicUNIPublicNNIPrivateUNIPrivateSwitchPublicSwitchCarriersPublicSwitchCarrierComputerRaj Jain8ATM InterfacesATM InterfacesUser to Network Interface (UNI): Public UNI, Private UNINetwork to Node Interface (NNI): Private NNI (P-NNI)Public NNI =Inter-Switching System Interface (ISSI)Intra-LATA ISSI (Regional Bell Operating Co)Inter-LATA ISSI (Inter-exchange Carriers) Broadband Inter-Carrier Interface (B-ICI)Data Exchange Interface (DXI)Between routers and ATM Digital Service Units (DSU)Raj Jain9ATM LayerATM Adaptation LayerPhysicalLayerATM LayerPhysicalLayerATM LayerATM Adaptation LayerPhysicalLayerEnd System End SystemSwitchProtocol LayersProtocol LayersRaj Jain10Protocol LayersProtocol LayersThe ATM Adaptation LayerHow to break messages to cellsThe ATM LayerTransmission/Switching/ReceptionCongestion Control/Buffer managementCell header generation/removal at source/destinationCell address translationSequential deliveryRaj Jain11Cell Header FormatCell Header FormatGFC = Generic Flow Control(Was used in UNI but not in NNI)VPI/VCI = 0/0  Idle cell; 0/n  SignalingHEC: 1 + x + x2 + x8VCI PTIHeader Error Check (HEC)VCIVPI VCIGFC/VPI VPICLPPayloadRaj Jain12Path vs ChannelsPath vs Channels24/28-bit connection identifierFirst 8/12 bits: Virtual Path, Last 16 bits: Virtual CircuitVP service allows new VC's w/o orders to carriersVC1VC2VC3VC1VC2VC3VC1VC2VC3VP1VP2VP3LinkRaj Jain13VP/VC Assignment/UseVP/VC Assignment/UseSwitch33 56Video Data37 34VoiceData213453556657661122Port1/373/345/332/56VPI/VCIIn1/352/564/654/76VPI/VCI3456PortOutRaj Jain14Original Classes of Original Classes of TrafficTrafficClass A Class B Class C Class DTime Sync Yes Yes No NoBit Rate Constant Variable Variable VariableConnection-OrientedYes Yes Yes NoExamples CircuitEmulationComp.VideoFrameRelaySMDSAAL AAL1 AAL2 AAL3 AAL4Raj Jain15AAL 5AAL 5Designed for data trafficLess overhead bits than AAL 3/4  Simple and Efficient AAL (SEAL)No per cell length field, No per cell CRCPADUserPayloadLength CRC-32Control4220-64kB10PTI bit indicates last cell0-47Raj Jain16AAL2AAL2Ideal for low bit rate voiceVariable/constant rate voiceMultiple users per VCCompression and Silence suppressionIdle channel suppressionCellHeaderCellHeaderPayload 1PktHdrPayload 2 Payload 3PktHdrPktHdrPayload 1PktHdrPayload 2 Payload 3PktHdrPktHdrPayload 1 Payload 2 Payload 3Raj Jain17Physical MediaPhysical MediaMultimode Fiber: 100 Mbps using 4b/5b, 155 Mbps SONET STS-3c, 155 Mbps 8b/10bSingle-mode Fiber: 155 Mbps STS-3c, 622 MbpsPlastic Optical Fiber: 155 MbpsShielded Twisted Pair (STP): 155 Mbps 8b/10bCoax: 45 Mbps, DS3, 155 MbpsUnshielded Twisted Pair (UTP)UTP-3 (phone wire) at 25.6, 51.84, 155 MbpsUTP-5 (Data grade UTP) at 155 MbpsDS1, DS3, STS-3c, STM-1, E1, E3, J2, n × T1Raj Jain18SummarySummaryATM Overview: History, Why and WhatProtocol Layers: AAL, ATM, Physical layers, Cell formatInterfaces: PNNI, NNI, B-ICI, DXIABR, CBR, VBR, UBR, GFRRaj Jain19ATM : Key ReferencesATM : Key ReferencesG. Sackett and C. Y. Metz, “ATM and Multiprotocol Networking,” McGraw-Hill, 1997 (Technical).K. Siu and R. Jain, "A Brief Overview of ATM: Protocol Layers, LAN Emulation, and Traffic Management," Computer Communications Review (ACM SIGCOMM), April 1995, http://www.cis.ohio-state.edu/~jain/ ATM Forum specs are available at ftp://ftp.atmforum.com/pub/approved-specs/For additional references, see

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