A Review of Key Networking ConceptsSlide 2ISO/OSI Reference ModelTCP/IP Reference ModelLayered Packet FormatCoding TerminologyChannel CapacityChannel Capacity (Cont)Data vs SignalBit StuffingFlow ControlError ControlConnection-Oriented vs ConnectionlessMultiple Access ProtocolsSlide 15Interconnection DevicesSlide 17IEEE 802 Address FormatSummaryHomeworkRaj JainThe Ohio State University1A Review of Key A Review of Key Networking ConceptsNetworking ConceptsRaj Jain The Ohio State UniversityColumbus, OH [email protected] slides are available athttp://www.cse.ohio-state.edu/~jain/cis777-99/Raj JainThe Ohio State University2ISO/OSI Reference ModelEthernet/IEEE 802.3 LANsInterconnecting DevicesAll these concepts are taught in CIS677.OverviewRaj JainThe Ohio State University3ISO/OSI Reference ModelISO/OSI Reference ModelApplicationPresentationSessionTransportNetworkDatalinkPhysicalHow to transmit signal: CodingTwo party communication: EthernetRouting, Addressing: IPEnd-to-end communication: TCPFile transfer, Email, Remote LoginASCII Text, SoundEstablish/manage connection123Raj JainThe Ohio State University4TCP/IP Reference ModelTCP/IP Reference ModelTCP = Transport Control ProtocolIP = Internet Protocol (Routing)ApplicationPresentationSessionTransportNetworkDatalinkPhysicalApplicationTransportInternetworkHost to NetworkFTPTCPIPEthernetTelnet HTTPUDPPacketRadioPoint-to-PointTCP/IP Ref Model OSI Ref ModelTCP/IP ProtocolsRaj JainThe Ohio State University5Layered Packet FormatLayered Packet FormatNth layer control info is passed as N-1th layer data.FTP DataFTP HeaderTCP DataTCPHeaderIP DataIPHeaderEthernet DataEthernetHeaderEthernetTrailerRaj JainThe Ohio State University6Coding TerminologyCoding TerminologySignal element: PulseModulation Rate: 1/Duration of the smallest element=Baud rateData Rate: Bits per secondData Rate = Fn(Bandwidth, signal/noise ratio, encoding)PulseBit+5V0-5VRaj JainThe Ohio State University7Channel CapacityChannel CapacityCapacity = Maximum data rate for a channelNyquist Theorem:Bilevel Encoding: Data rate = 2  Bandwidth05VMultilevel coding: Data rate = 2  Bandwidth  log2 MExample: M=4, Capacity = 4  Bandwidth0001101110Raj JainThe Ohio State University80011Channel Capacity (Cont)Channel Capacity (Cont)Bilevel Encoding: Worst case: 1010101010Cycle time = 2  Bit time  Data rate = 2  BandwidthMultilevel coding: Worst case 0011001100110011Cycle time = 4 Bit time  Data rate = 2  Bandwidth  log2 M0005V1011 110011001100Raj JainThe Ohio State University9T RData Signal Data1010Data vs SignalData vs SignalData: Analog (Music), Digital (files)Signal: Analog (POTS, Radio), Digital (ISDN)Data Signal ExamplesAnalog Analog Modulation AM, FMDigital Analog Coding/Keying ASK, FSK, PSKAnalog Digital Modulation PCM, ADPCMDigital Digital Coding Manchester, NRZRaj JainThe Ohio State University10Bit StuffingBit StuffingDelimit with special bit pattern (bit flags)Stuff bits if pattern appears in dataRemove stuffed bits at destinationTransmitterReceiver0 11111 11111 11111 1001001111110 0 1111110 111110 111110 10010 011111100 11111 11111 11111 10010FlagRaj JainThe Ohio State University11Flow ControlFlow ControlFlow Control = Sender does not flood the receiver, but maximizes throughputSender throttled until receiver grants permissionMethods:Stop and waitSliding windowRaj JainThe Ohio State University12Error ControlError ControlError Control = Deliver frames without error, in the proper order to network layerError control Mechanisms:Ack/Nak: Provide sender some feedback about other endTime-out: for the case when entire packet or ack is lostSequence numbers: to distinguish retransmissions from originalsARQ: Stop and Wait, Selective Reject, Go-back nRaj JainThe Ohio State University13Connection-Oriented vs Connection-Oriented vs ConnectionlessConnectionlessConnection-Oriented: Telephone SystemPath setup before data is sentData need not have address. Circuit number is sufficient.Connectionless: Postal System.Complete address on each packetThe address decides the next hop at each routerRaj JainThe Ohio State University14Multiple Access ProtocolsMultiple Access Protocols(a) Multiple Access(b) Carrier-Sense Multiple Access with Collision DetectionRaj JainThe Ohio State University15Multiple Access ProtocolsMultiple Access ProtocolsAloha at University of Hawaii: Transmit whenever you likeWorst case utilization = 1/(2e) =18%CSMA: Carrier Sense Multiple Access Listen before you transmitCSMA/CD: CSMA with Collision DetectionListen while transmitting. Stop if you hear someone else.Ethernet uses CSMA/CD.Standardized by IEEE 802.3 committee.Raj JainThe Ohio State University16Interconnection DevicesInterconnection DevicesRepeater: PHY device that restores data and collision signalsHub: Multiport repeater + fault detection and recoveryBridge: Datalink layer device connecting two or more collision domains. MAC multicasts are propagated throughout “extended LAN.”Router: Network layer device. IP, IPX, AppleTalk. Does not propagate MAC multicasts.Switch: Multiport bridge with parallel pathsThese are functions. Packaging varies.Raj JainThe Ohio State University17Interconnection DevicesInterconnection DevicesH HBH HRouterExtended LAN=Broadcast domainLAN=CollisionDomainNetworkDatalinkPhysicalTransportRouterBridge/SwitchRepeater/HubGatewayApplicationNetworkDatalinkPhysicalTransportApplicationRaj JainThe Ohio State University18IEEE 802 Address FormatIEEE 802 Address FormatMulticast = “To all bridges on this LAN”Broadcast = “To all stations” = 111111....111 = FF:FF:FF:FF:FF:FF48-bit:1000 0000 : 0000 0001 : 0100 0011 : 0000 0000 : 1000 0000 : 0000 1100 = 80:01:43:00:80:0CIndividual/GroupUniversal/Local24 bits assigned by OUI Owner1 1 2224Organizationally Unique Identifier (OUI)Raj JainThe Ohio State University19SummarySummaryISO/OSI reference model has seven layers.TCP/IP Protocol suite has four layers.Ethernet/IEEE 802.3 uses CSMA/CD.Addresses: Local vs Global, Unicast vs Broadcast.Raj JainThe Ohio State University20HomeworkHomeworkFor each of the following addresses: indicate whether it is a multicast and whether it is a locally assigned address?80:02:45:00:00:0040:02:45:00:00:01Were these addresses assigned by the same