Raj JainThe Ohio State University1SONETSONETSONETRaj JainProfessor of CISThe Ohio State UniversityColumbus, OH [email protected]://www.cis.ohio-state.edu/~jain/Raj JainThe Ohio State University2SONETSONETSONETq Synchronous Optical Networkq Standard developed by ANSI and Exchange CarrierStandards Association (ECSA)q CCITT: Synchronous Digital Hierarchy (SDH)q SONET links can be used in place of dark fiberSONET LinkRaj JainThe Ohio State University3Two Views of SONETTwo Views of SONETTwo Views of SONETRaj JainThe Ohio State University4Protocol Components of SONETProtocol Components of SONETProtocol Components of SONETq Photonic Layer: Characteristics of fibers, transmitters,receivers and encoding (ANSI T1.106-1988)q Section Layer: Transmission across a single link. Framing,scrambling, and error monitoring.q Line Layer: Signaling between multiplexer switches. Framesynchronization. Multiplexing of data in to SONET frames.q Path Layer: End-to-end signaling issues. Mapping DS3,FDDI, BISDN into SONET payload.LLCMACPHYPMDPathLineSectionPhotonicTransportNetworkDatalinkPhysicalFDDIProtocolsSONETProtocolsRaj JainThe Ohio State University5Physical Components of SONETPhysical Components of SONETPhysical Components of SONETq Section: Single run of fiber. Clock synchronization andtiming issuesq Line: Sections connected via repeaters. Betweenmultiplexers or switchesq Path: End-to-endSection Section SectionTerminalsMultiplexerRepeaterAdd-DropMultiplexerRepeaterMultiplexerTerminalsSectionLinePathLineRaj JainThe Ohio State University6Protocol HierarchyProtocol HierarchyProtocol HierarchyPathLineSectionPhotonicPathLineSectionPhotonicTerminal RegeneratorSTS MultiplexerTerminalPhotonic PhotonicSectionSectionLineEnvelopeSTS-N BlockFrameLightRaj JainThe Ohio State University7SONET/SDH Signal HierarchySONET/SDH Signal HierarchySONET/SDH Signal HierarchyANSIDesignationOpticalSignalCCITTDesignationData Rate(Mbps)Payload Rate(Mbps)STS-1 OC-1 51.84 50.112STS-3OC-3STM-1155.52150.336STS-9 OC-9 STM-3 466.56 451.008STS-12OC-12STM-4622.08601.344STS-18OC-18STM-6933.12902.016STS-24OC-24STM-81244.161202.688STS-36OC-36STM-121866.241804.032STS-48 OC-48 STM-16 2488.32 2405.376STS-96OC-96STM-324976.644810.176STS-192 OC-192 STM-64 9953.28 9620.928Synchronous Transport Signal Level n = STS-n = n × 51.84 MbpsSTM=Synchronous Transport Module, OC=Opical Carrier levelRaj JainThe Ohio State University8Byte MultiplexingByte MultiplexingByte Multiplexingq Also known as byte interleavingq Easier to view in two dimensionB2 A2 C1 B1 A1C2A1A2B1B2C1C2A3B3C3C3C2C1B3B2B1A3A2A1C3C2C1B3B2B1A3A2A1Raj JainThe Ohio State University987 ColumnsSTS-1 Frame FormatSTS-1 Frame FormatSTS-1 Frame Formatq Overhead = Header. 810 Bytes/125 ms = 51.84 MbpsOverhead3 ColumnsLineOverhead6 RowsSectionOverhead3 RowsPathOverhead1 Column90 ColumnsSynchronous Payload Envelope9 RowsRaj JainThe Ohio State University10MultiplexingMultiplexingMultiplexing155.52 MbpsOverheadSTS-1Payload51.84 MbpsOverheadSTS-1Payload51.84 MbpsOverheadSTS-1Payload51.84 MbpsRaj JainThe Ohio State University11ConcatenationConcatenationConcatenationSTS-3c Payload155.52 MbpsOverheadOverheadSTS-1Payload51.84 MbpsOverheadSTS-1Payload51.84 MbpsOverheadSTS-1Payload51.84 MbpsRaj JainThe Ohio State University12STS-3c Frame FormatSTS-3c Frame FormatSTS-3c Frame Formatq STS-3c is similar to STM-1Payload261 ColumnsOverhead9 Columns270 Columns9 RowsRaj JainThe Ohio State University13Location of SPE in STS-1Location of SPE in STS-1Location of SPE in STS-1q SPE supplied by the user ⇒ Can arrive at any time ⇒ SPEcan straddle two successive STS-1 framesPathOverhead3 ColumnsFrame 0 9 RowsFrame 19 Rows87 Columns87 Columns9 RowsRaj JainThe Ohio State University14ScramblingScramblingScramblingq SONET uses NRZ coding. 1 = Light On, 0 = Light Off.q Too many 1’s or 0’s ⇒ Loss of bit clocking informationq All bytes (except some overhead bytes) are scrambledq Polynomial 1 + x6 + x7 with a seed of 1111111 is used togenerate a pseudorandom sequence, which is XOR’ed toincoming bits.1111 1110-0000 0100-0001 1000-0101 0001-1110 0100-0101 1001-1101 0100-1111 1010-0001 1100-0100 1001-1011 0101-1011 1101-1000 1101-0010 1110-1110 0110-0101 010q If user data is identical to (or complement of) thepseudorandom sequence, the result will be all 0’s or 1’s.Raj JainThe Ohio State University15SummarySummarySummaryq T1, DS1, DS3, ...q SONETq SDHq STS-n, STM-nq STS-3cRaj JainThe Ohio State University16STS-1 Overhead BytesSTS-1 Overhead BytesSTS-1 Overhead BytesFramingA1BIP-8B1Data ComD1PointerH1BIP-8B2Data ComD4Data ComD7Data ComD10GrowthZ1FramingA2OrderwireE1Data ComD2PointerH2APSK1Data ComD5Data ComD8Data ComD11GrowthZ2OrderwireE2GrowthZ5Data ComD12Data ComD9Data ComD6APSK2Pointer ActionH3Data ComD3UserF1STS-1 IDC1TraceJ1BIP-8B3Signal LabelC2Path StatusG1User ChannelF2MultiframeH4GrowthZ3GrowthZ4Section OverheadPathLayerOverheadLine OverheadRaj JainThe Ohio State University17STS-3c Overhead bytesSTS-3c Overhead bytesSTS-3c Overhead bytesK1B1D1H1B2 B2E1D2H2A2 C1F1D3H3K2J1B3C2A1 A1 A2 A2 C1 C1H1 H1 H2 H2 H3 H3B2D4D7D10Z1 Z1 Z1 Z2 Z2 Z2 Z5Z4Z3D5D8D11D6D9D12E2G1F2H4A1(a) Section and line overhead(b) Path
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