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Packet-Over-SONET (POS)A Technical PrimerIEEE 802.3 HSSGNovember 8-12, 1999HawaiiGary Nichollgnicholl@cisco.com1

What is POS ?Packet-over-SONET (POS) is astandardized way for mapping IPpackets into SONET/SDH frames.2

Overview Network ModelEncapsulationSONET Overhead UsagePerformance MonitoringSynchronizationJitter RequirementsOC-192 PHYs3

POS Deployment First deployed in 1996 (OC-3c) Used in 100s of networks worldwide Over 15,000 POS interfaces deployed Defacto for building large IP backbones Available for OC-3c, OC-12c, and OC-48c today OC-192c demonstrated last week ! Standards based: IETF, Bellcore, ITU, ANSI4

Network Model - sponderOpticalMux/AmpRegenPOS - Packet over SONET/SDH OC-3c OC-12c OC-48c OC-192c(155.52 Mbps)(622.08 Mbps)(2488.32 Mbps)(9953.28 Mbps)5

Packet-over-SONET/SDH (PoS)DatagramsIPProtocol encapsulationLink InitializationPPP Packet DelineationError ControlPPP In ByteSynchronousHDLC FramingByte DelineationSONET/SDHNetwork LayerData Link LayerPhysical Layer Point-to-Point Protocol, IETF RFC 1661 PPP in HDLC- Like Framing, IETF RFC 1662 PPP over SONET/SDH, IETF RFC 1619/26156

POS Packet FlowSpecial Data Scrambler 1 x43 Polynomial Protects Against Transmitted FramesContaining Synch Bytes Or InsufficientOnes DensityStandard PPP Encapsulation Magic Number Recommended No Address and Control Compression No Protocol Field -1662Standard CRC Computation OC3 May Use CRC-16 Other Speeds Use ramingBellcoreITUANSISONET Framing OC3, OC12, OC48, OC192 Defined C2 Byte 0x16 With Scrambling C2 Byte 0xCF Without (OC-3)7

POS - Overhead UsagePathOverheadTransport OverheadA1 A1 A1A1A2 A2 A2A2J0 Z0 Z0C1 C2 C3Z0C192J1SectionB1OverheadE1F1B3D1D2D3C2H1 H1 H1H1H2 H2 H2H2H3 H3 2Z4Z2E2Z5384385S11Z1Z1Z123192Z2Z2 M1193 194195Undefined bytes576Defined and used by POSDefined but not used by POS8

Performance Monitoring &Fault Management Performance Monitoring (Proactive)Error counts B1, B2, B3Errors counts Line (M1) and Path (G1) REIThreshold crossing alerts (TCA) for B1,B2,B3 Alarm Reporting (Reactive)LOS, LOF, LAIS, LRDIPLOP, PAIS, PRDISF, SD based on B2 with selectable threshold Signal Label (C2: CF or 16) Path Trace (J1) insertion and monitoringAlarm HierarchyLOS LOF LAIS LRDI PAIS PRDI LOP Sync Status (S1) set to ‘don’t use for sync’9

POS - SynchronizationLock to worst caseSONET clock (20ppm)20 ppm. Standby Osc.Router AFABRICRouter BPOS LCf1ADMSONETADMNETWORK(PRS)f1ST1POS LC20 ppm20 ppmPOS LCTPOS LCf1POS LCDWDMNetworkRPOS LCTPacketI/FTrafficTimingOscillator10

POS Jitter RequirementsPOSLine CardSONET/SDHNetwork80 kmADMRRRADMRPOSLine CardDCSADMST1 Jitter Generation (Tx) Jitter Tolerance (Rx) Jitter TransferPOSLine CardDWDM/OpticalNetworkTRNRRPOSLine CardTRN500 km Jitter Generation (Tx) Jitter Tolerance (Rx)ADM: Add Drop MuxTRN: TransponderR:RegeneratorPOS Interfaces are SONET/SDH Jitter Compliant11

OC-192 POS LC ArchitectureOC-192 xLaserDmxRecSONET Framed16 x 622 Mb/sLVDS(OIF 99.102)12

POS OC-192 Interface OptionsOC-192 /OMuxConvASICOC-192Framer single strand SMF 80kmOC-192 VSR12x1.24GOC-192FramerConvASIC 16/12 8B10B AlgnE/O(12) O/E(12)O/E(12) E/O(12)OC-192Framer 12 strand MMF 500m13

Summary POS is a widely deployed, standardizedmapping of IP into SONET/SDH The HSSG could draw upon the experience ofPOS to speed up the definition of the 10GEWAN PHY.14

Packet-Over-SONET (POS) A Technical Primer IEEE 802.3 HSSG November 8-12, 1999 Hawaii Gary Nicholl gnicholl@cisco.com. 2 What is POS ? Packet-over-SONET (POS) is a . Network POS LC POS LC Lock to worst case SONET clock (20ppm) 20 ppm. Standby Osc. 20 ppm 20 ppm f1 Traffic Oscillator Timing R T T. 11