ATM Traffic Management and LAN EmulationOverviewDime SaleFutureTraffic Management on the Info SuperhighwayTraffic Mgmt FunctionsService CategoriesSlide 8ABR: Binary Rate-based SchemeThe Explicit Rate SchemeLAN EmulationFeaturesSlide 13Protocol Layers (Cont)Slide 15OperationOperation (Cont)Flush ProtocolLANE v2.0LANE v2.0 (Cont)ATM Virtual LANsSummaryHomeworkRaj JainThe Ohio State University12-1ATM Traffic Management ATM Traffic Management and LAN Emulationand LAN EmulationRaj JainProfessor of Computer and Information SciencesThe Ohio State UniversityColumbus, OH [email protected] slides are available on-line at:http://www.cse.ohio-state.edu/~jain/cis677-00/Raj JainThe Ohio State University12-2OverviewOverviewATM Classes of ServiceATM Traffic ManagementAvailable Bit Rate (ABR)LAN Emulation (LANE)LANE V2.0.Raj JainThe Ohio State University12-3Dime SaleDime SaleOne Megabit memory, One Megabyte disk, One Mbps link, One MIP processor, 10 cents each.....Raj JainThe Ohio State University12-4FutureFutureIn 1990, the memory will be so cheap that you will not have to worry about paging, swapping, virtual memory, memory hierarchy, and....Year1980Raj JainThe Ohio State University12-5153246CACUPCSelectiveFrameDiscardShapingSchedulingTraffic Monitoring and feedback7Traffic Management on Traffic Management on the Info Superhighwaythe Info SuperhighwayRaj JainThe Ohio State University12-6Traffic Mgmt FunctionsTraffic Mgmt FunctionsConnection Admission Control (CAC): Can quality of service be supported?Traffic Shaping: Limit burst length. Space-out cells.Usage Parameter Control (UPC): Monitor and control traffic at the network entrance.Network Resource Management: Scheduling, Queueing, resource reservationPriority Control: Cell Loss Priority (CLP)Selective Cell Discarding: Frame DiscardFeedback Controls: Network tells the source to increase or decrease its load.Raj JainThe Ohio State University12-7StandbyJoy RidersGuaranteedConfirmedService CategoriesService CategoriesRaj JainThe Ohio State University12-8Service CategoriesService CategoriesABR (Available bit rate): Source follows network feedback. Max throughput with minimum loss. UBR (Unspecified bit rate): User sends whenever it wants. No feedback. No guarantee. Cells may be dropped during congestion.CBR (Constant bit rate): User declares required rate.Throughput, delay and delay variation guaranteed.VBR (Variable bit rate): Declare avg and max rate.rt-VBR (Real-time): Conferencing.Max delay guaranteed.nrt-VBR (non-real time): Stored video.Raj JainThe Ohio State University12-9ABR: Binary Rate-based SchemeABR: Binary Rate-based SchemeExplicit forward congestion indicator (EFCI) set to 0 at sourceCongested switches set EFCI to 1Every nth cell, destination sends an resource management (RM) cell to the source indicating increase amount or decrease factorEFCIDestinationDestinationSourceSourceRMRaj JainThe Ohio State University12-10The Explicit Rate SchemeThe Explicit Rate SchemeSources send one RM cell every n cellsThe RM cells contain “Explicit rate”Destination returns the RM cell to the sourceThe switches adjust the rate down Source adjusts to the specified rateExplicit RateExplicit RateCurrent Cell RateCurrent Cell RateRaj JainThe Ohio State University12-11LAN EmulationLAN EmulationProblem: Need new networking s/w for ATMSolution: Let ATM network appear as a virtual LANLAN emulation implemented as a device driver below the network layerBridge BridgeATMRaj JainThe Ohio State University12-12Features Features One ATM LAN can be n virtual LANsLogical subnets interconnected via routersNeed drivers in hosts to support each LANOnly IEEE 802.3 and IEEE 802.5 frame formats supported. (FDDI can be easily done.)Doesn't allow passive monitoringNo token management (SMT), collisions, beacon frames. Allows larger frames.IEEE 802.3 or 802.5 FrameLE Header (2 Bytes)Raj JainThe Ohio State University12-13Protocol LayersProtocol LayersApplica-tionsPhysicalLayerLANEmulationIP IPXNDIS ODIAAL5ATMPhyLayerATMLANEmulationPhyLayerAAL5ATMPhyLayerMediaAccessControlBridgingPhyLayerApplica-tionsPhysicalLayerMediaAccessControlIP IPXNDIS ODIATM HostATM SwitchATM-LAN BridgeLAN HostATMSwitchATMSwitchBridgeBridgeRaj JainThe Ohio State University12-14Protocol Layers (Cont)Protocol Layers (Cont)NDIS = Network Driver Interface SpecificationODI = Open Datalink InterfaceIPX = NetWare Internetworking ProtocolLAN Emulation Software:LAN Emulation Clients in each hostLAN Emulation ServersLAN Emulation Configuration server (LECS)LAN Emulation Server (LES)Broadcast and unknown server (BUS)Raj JainThe Ohio State University12-15LAN EmulationLAN EmulationLAN Emulation Server ATM client BBridge2. Client sends messages on the VC1. Client gets recipient's address from LES and sets-up a VC.Broadcast/Unknown Server (BUS)Non-ATM client4. Messages for non-ATM clients are forwarded through bridges3. Messages for ATM clients are delivered directly.SwitchesRaj JainThe Ohio State University12-16OperationOperationInitialization: Client gets address of LAN Emulation Configuration Server (LECS) from its switch, uses well-known LECS address, or well known LECS PVCClient gets Server's address from LECSRegistration: Client sends a list of its MAC addresses to Server.Declares whether it wants ARP requests.Raj JainThe Ohio State University12-17Operation (Cont)Operation (Cont)Address Resolution: Client sends ARP request to Server. Unresolved requests sent to clients, bridges.Server, Clients, Bridges answer ARPClient setups a direct connectionBroadcast/Unknown Server (BUS): Forwards multicast traffic to all membersClients can also send unicast frames for unknown addressesRaj JainThe Ohio State University12-18Flush ProtocolFlush ProtocolClients can send unicast packets via BUS while trying to resolve the address  Out-of-order arrivalsWhen the direct VCC is setup, clients send a “Flush message” to destination. Destination returns it to source. Source can then send packets on direct VC.Client A Client BBUSDirectFlush FlushRaj JainThe Ohio State University12-19LANE v2.0LANE v2.0Allows multiple LE Servers: LES, BUS, and LECS on a single ELANLAN Emulation network-to-network interface (LNNI): Specifies interfaces for communication between the LE server entities. Physical ELAN 1Physical ELAN