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SONET Technology Primer by Martin Schulman. Slide 2 COMPANY CONFIDENTIAL NANOG, May 23-25 Copyright © 1999, Juniper Networks, Inc. Topics To Be Covered.

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Presentation on theme: "SONET Technology Primer by Martin Schulman. Slide 2 COMPANY CONFIDENTIAL NANOG, May 23-25 Copyright © 1999, Juniper Networks, Inc. Topics To Be Covered."— Presentation transcript:

1 SONET Technology Primer by Martin Schulman

2 Slide 2 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Topics To Be Covered Motivation & History Motivation & History Termination Equipment And Frame Formats Termination Equipment And Frame Formats Electrical And Optical Encoding Electrical And Optical Encoding Topologies And Redundancy Topologies And Redundancy PPP Over SONET PPP Over SONET Relationship To Other Standards Relationship To Other Standards

3 Slide 3 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. <1984 NA Digital Telephony Key System Aspects: M13 Building Blocks M13 Building Blocks Asynchronous Operation Asynchronous Operation Electrical DS3 Signals Electrical DS3 Signals Proprietary Fiber Systems Proprietary Fiber Systems Brute Force Cross Connect Brute Force Cross Connect AT&T Network/Western Electric Equipment AT&T Network/Western Electric Equipment CentralOffice CentralOffice CentralOffice Fiber Fiber Optic TransmissionSystems Switches Switches Leased Line Leased Line M13M13 DS3 DS1 DS3 DS1 Cross Connect M13 DS1 DS1 No Guaranteed TimingSynchronization

4 Slide 4 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Post-Divestiture Dilemmas Faster Fiber Coming: Need Mid-Span Meet Need Mid-Span Meet Support New Services Support New Services Allow Other Topologies Allow Other Topologies Standardize Redundancy Standardize Redundancy Common OAM&P Common OAM&P Scalable Cross Connect Scalable Cross Connect DifferentCarriers,Vendors Switches Switches Leased Line Leased Line LAN Services LAN Services Data Services Data Services M13 SupportOtherTopologies, Protect Fibers DS1 Internal DS3 Cross Connect

5 Slide 5 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. The Standards Process SONET/SDHStandardsApproved ANSI Approves SYNTRAN Divestiture Exchange Carriers Standards Associate (ECSA) T1 Committee Formed ANSI T1X1 ApprovesProject Bellcore Proposed SONET Principles To ANSI T1X1 CCITT Expresses Internet in SONET British and Japanese Participation in T1X1 CCITT XVIII Begins Study Group CEPT Proposes Merged ANSI/CCITT Standard US T1X1 Accepts Modifications Standard That Almost Wasnt >400 Technical Proposals >400 Technical Proposals Rate Discussions AT&T vs. Bellcore Rate Discussions AT&T vs. Bellcore International Changes For Byte/Bit Interleaving, Frames, Data Rates International Changes For Byte/Bit Interleaving, Frames, Data Rates Phase I, II, III Separate APS, etc. Phase I, II, III Separate APS, etc. SONET Concept Developed By Bellcore

6 Slide 6 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. SONET Defined Synchronous Optical Network Synchronous Optical Network Set of Layer 1 Standards For Communication over Fiber Optic (and Electrical) Links In Order To Facilitate: Set of Layer 1 Standards For Communication over Fiber Optic (and Electrical) Links In Order To Facilitate: Fiber Optic Link Speed Increases Fiber Optic Link Speed Increases Variety Of Topologies and Grooming Functions Variety Of Topologies and Grooming Functions Operations, Administration, Maintenance, and Provisioning (OAM&P) Operations, Administration, Maintenance, and Provisioning (OAM&P) When Used As Telephony Carrier Equipment And CPE Interconnect When Used As Telephony Carrier Equipment And CPE Interconnect

7 Slide 7 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Equipment Types PTE All Perform Electro-Optical Conversion Section Termination (STE) Section Termination (STE) Line Termination (LTE) Line Termination (LTE) Path Termination (PTE) Path Termination (PTE) Data Between PTE May Traverse Multiple LTE, STE Line SONET End Device - I.e. Telephony Switch, Router Path Sections Repeaters PTE

8 Slide 8 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. STS-1 Frame Format 90 Bytes Or Columns 9Rows Each Small Rectangle Represents One Byte Transmitted MSB First Frame Transmission Top Row First, Sent Left To Right Top Row First, Sent Left To Right 125 s/Frame 125 s/Frame 810 Bytes/Frame 810 Bytes/Frame Mbps Rate Mbps Rate Frame Contains One Payload Frame Contains One Payload

9 Slide 9 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Section Overhead (SOH) A1=0xF6A2=0x28J0/Z0STS-ID B1BIP-8E1OrderwireF1User D1 Data Com D2 D3 Section Overhead 9 Bytes Total 9 Bytes Total Originated And Terminated By All Section Devices (Regenerators, Multiplexers, CPE) Originated And Terminated By All Section Devices (Regenerators, Multiplexers, CPE) Other Fields Pass Unaffected Other Fields Pass Unaffected RcvSOH A1,A2 - Framing Bytes A1,A2 - Framing Bytes J0/Z0 - Section ID, Reserved J0/Z0 - Section ID, Reserved BIP-8 - Bit Interleaved Parity BIP-8 - Bit Interleaved Parity E1 Orderwire - Craft Voice Interface Between Sections E1 Orderwire - Craft Voice Interface Between Sections F1 User - Proprietary Management F1 User - Proprietary Management D1-D Kbps OSI/CMIP Channel D1-D Kbps OSI/CMIP Channel XmtSOH

10 Slide 10 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Line Overhead (LOH) H1PointerH2PointerH3 Pointer Act B2BIP-8K1APSK2APS D4 Data Com D5 D6 Line Overhead 18 Bytes Total 18 Bytes Total Originated And Terminated By All Section Devices (Regenerators, Multiplexers, CPE) Originated And Terminated By All Section Devices (Regenerators, Multiplexers, CPE) LOH+SOH=TOH (Transport OH) LOH+SOH=TOH (Transport OH) H1-3 - Payload Pointers H1-3 - Payload Pointers BIP-9 Bit Parity BIP-9 Bit Parity K1, K2 - Automatic Protection Switching K1, K2 - Automatic Protection Switching D4-D kbps OSI/CMIP D4-D kbps OSI/CMIP S1 - Time Sync Indicator S1 - Time Sync Indicator M0 - Return Error Indicator M0 - Return Error Indicator E1 Orderwire - Craft Voice Interface Between Sections E1 Orderwire - Craft Voice Interface Between Sections D7 Data Com D8 D9 D10 D11 D12 S1SyncM0REIE1Orderwire RcvSOHXmtSOH XmtSOH XmtLOH RcvSOH RcvLOH

11 Slide 11 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Path Overhead (POH) J1Trace B3BIP-8 C2 Sig Label Path Overhead H1,H2 Point To Beginning - Beginning Floats Within Frame H1,H2 Point To Beginning - Beginning Floats Within Frame 9 Bytes (1 Column) Spans Frames 9 Bytes (1 Column) Spans Frames Originated And Terminated By All Path Devices (I.e. CPE, Switches) Originated And Terminated By All Path Devices (I.e. CPE, Switches) STE Can Relocate Payload STE Can Relocate Payload J1- Repeated ID String J1- Repeated ID String BIP-8 - Parity BIP-8 - Parity C2 - Payload Type Indicator C2 - Payload Type Indicator G1 - End End Path Status G1 - End End Path Status F2 - User F2 - User H4 - Use Depends On Payload H4 - Use Depends On Payload Z3-5 - Future Growth Z3-5 - Future Growth G1 Path Stat F2User H4Indicator PTE Z3Growth Z4Growth Z5Tandem PTESTE Frame N Frame N+1 Frame N Frame N+1

12 Slide 12 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. SPE Synchronous Payload Envelope Contains POH + Data Contains POH + Data First Byte Follows First Byte Of POH First Byte Follows First Byte Of POH Wraps In Subsequent Columns Wraps In Subsequent Columns May Span Frames May Span Frames Up To Single Data Signal - Enough for DS3 Up To Single Data Signal - Enough for DS3 Defined Payloads Virtual Tributaries (For DS1, DS2) Virtual Tributaries (For DS1, DS2) DS3 DS3 SMDS SMDS ATM ATM PPP PPP More... More...

13 Slide 13 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Accommodating Jitter Positive Stuff Negative Stuff Byte After H3 Ignored, Or H3 Holds Extra Byte To Shorten/Lengthen Frame H1, H2 Values Indicate Changes - Maximum Every 4 Frames Requires Close (Not Exact) Clock Synchronization Among Elements

14 Slide 14 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Clock Synchronization Building Integrated Timing System Hierarchical Clocking Distribution Hierarchical Clocking Distribution Normally All Synchd To Stratum 1 (Can Be Cesium/Rubidium Clock) Normally All Synchd To Stratum 1 (Can Be Cesium/Rubidium Clock) Dedicated Link Or Recovered Dedicated Link Or Recovered Fallback To Higher Stratum In Failure (Temperature Controlled Crystal) Fallback To Higher Stratum In Failure (Temperature Controlled Crystal) PTE PTE BITSBITS BITS PrimaryReference BackupReference Level 1: Level 1: Level 2: 1.6x10 -8Level 2: 1.6x10 -8 Level 3: 4.6x10 -6Level 3: 4.6x10 -6 Level 4: 32x10 -6Level 4: 32x10 -6

15 Slide 15 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. STS-N Frame Format Composite Frames Byte Interleave STS-1s Byte Interleave STS-1s Clock Rate = Nx51.84 Mbps Clock Rate = Nx51.84 Mbps 90xN Bytes Or Columns N Individual STS-1 Frames Examples Examples STS Mbps STS Mbps STS Mbps STS Gbps STS Gbps

16 Slide 16 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. STS-Nc Frame Format Composite Frames Same TOH Structure And Data Rates As STS-N Same TOH Structure And Data Rates As STS-N Not All TOH Bytes Used Not All TOH Bytes Used First H1, H2 Point To POH First H1, H2 Point To POH Single Payload In Rest Of SPE Single Payload In Rest Of SPE Accommodates FDDI, E4, etc. Accommodates FDDI, E4, etc. 90xN Bytes Or Columns Examples Examples Only 1 BIP-8 for section layer (B1) Only One DCC (D1-D3) Only Two E1, E2 Orderwires Only One User (F1) Only One APS (K1 and K2) Only One DCC (D4-D12) TransportOverhead

17 Slide 17 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Transmission Encoding OC-N Is Optical Carrier STS-N Long Reach: 40 km 1310 or 1550 nm SM Intermediate Reach: 15 km 1310 or 1550 nm SM Short Reach:Long Reach 2 km 1310 nm MM E O Electrical Transmission Standard STS-1: B3ZS (BPV), 450 STS-1: B3ZS (BPV), 450 STS-3: Coded Mark Inversion, 225 STS-3: Coded Mark Inversion, 225 Useful Intra-Office Connection Useful Intra-Office Connection 1+x 6 +x 7 Scrambling Ensures Ones Density Ensures Ones Density Does Not Include A1, A2, C1 Bytes Does Not Include A1, A2, C1 Bytes Output Is NRZ Encoded Output Is NRZ Encoded

18 Slide 18 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Network Elements Nonstandard, Functional Names TM: Terminal Mux ADM: Add-Drop Mux DCC: Digital Cross Connect (Wideband and Broadband) (Wideband and Broadband) MN: Matched Node D+R: Drop and Repeat ADM TM DS1s DS1s MNMN MN DCC D+R D+R D+R MN

19 Slide 19 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Topology Building Blocks DCC ADM ADM ADM DCC ADM ADM ADM 2 Fiber Ring Each Line Is Full Duplex DCC ADM ADM ADM 4 Fiber Ring Each Line Is Full Duplex DCC ADM ADM ADM Uni- vs. Bi- Directional All Traffic Runs Clockwise, vs Either Way

20 Slide 20 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. OAM&P Manageability Is Required Well Defined Protocols, Alarms: Loss of Signal: All 0sLoss of Signal: All 0s Loss Of Frame: Cannot Find A1,A2Loss Of Frame: Cannot Find A1,A2 Alarm Indication Signal - Line: Remote Side Sees LOS or LOFAlarm Indication Signal - Line: Remote Side Sees LOS or LOF Remote Defect Indication - Line: Remote Seeing Above AlarmsRemote Defect Indication - Line: Remote Seeing Above Alarms Alarm Indication Signal - Path: Indication To Downstream Devices Of A ProblemAlarm Indication Signal - Path: Indication To Downstream Devices Of A Problem Remote Defect Indication - Path: Indication To Upstream Devices Of A ProblemRemote Defect Indication - Path: Indication To Upstream Devices Of A Problem SONET Processing Hardware OSI Node Hardware Error Detection Hardware Error Signaling DCC Links

21 Slide 21 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. APS ADM Line Protection Switching Uses TOH Trunk Application Backup Capacity Is Idle Supports 1:n, N=1-14 Automatic Protection Switching Line Or Path Based Line Or Path Based Revertive vs. Non-Revertive Revertive vs. Non-Revertive Mechanism For Intentional Cutover Mechanism For Intentional Cutover Restoration Times ~ 50 ms Restoration Times ~ 50 ms K1, K2 Bytes Signal Change K1, K2 Bytes Signal Change Common Uses: 2 Fiber UPSR or ULSR, 4 Fiber BPSR Common Uses: 2 Fiber UPSR or ULSR, 4 Fiber BPSR ADMADMADM Path Protection Switching Uses POH Access Line Applications Duplicate Traffic Sent On Protect 1+1 ADMADM

22 Slide 22 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Packet Over SONET (POS) PPPByteStuffFCSScramblingSONETFraming Standard PPP Encapsulation Magic Number Recommended Magic Number Recommended No Addres and Control Compression No Addres and Control Compression No Protocol Field Compression No Protocol Field Compression Standard CRC Computation OC3 May Use CRC-16 OC3 May Use CRC-16 Other Speeds Use CRC-32 Other Speeds Use CRC-32 Special Data Scrambler 1+ x43 Polynomial 1+ x43 Polynomial Protects Against Transmitted Frames Containing Synch Bytes Or Insufficient Ones Density Protects Against Transmitted Frames Containing Synch Bytes Or Insufficient Ones Density SONET Framing OC3, OC12, OC48, OC192 Defined OC3, OC12, OC48, OC192 Defined C2 Byte = 0x16 With Scrambling C2 Byte = 0x16 With Scrambling C2 Byte = oxCF Without (OC-3) C2 Byte = oxCF Without (OC-3)

23 Slide 23 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Technology Relationships Synchronous Digital Hierarchy (SDH) Synchronous Digital Hierarchy (SDH) International Diffs - Terms, OH Fields International Diffs - Terms, OH Fields Rates: STS-N -> STM-N/3 For N>=3 Rates: STS-N -> STM-N/3 For N>=3 SDL Proposal SDL Proposal Fix HDLC For High Speed Use Fix HDLC For High Speed Use Pt-Pt Links Without SONET Overhead Pt-Pt Links Without SONET Overhead WDM/DWDM: WDM/DWDM: More Capacity - Optical Routing For Redundancy More Capacity - Optical Routing For Redundancy No Access To Lower-Level (I.e. DS1 Signals) No Access To Lower-Level (I.e. DS1 Signals)

24 Slide 24 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. Acronyms ADM: Add-Drop Multiplex ADM: Add-Drop Multiplex APS: Automatic Protection Switching APS: Automatic Protection Switching BIP: Bit Interleaved Parity BIP: Bit Interleaved Parity BITS: Building Integrated Timing Supply BITS: Building Integrated Timing Supply OC: Optical Carrier OC: Optical Carrier POH: Path Overhead POH: Path Overhead POS: Packet Over SONET POS: Packet Over SONET PTE: Path Terminating Entity PTE: Path Terminating Entity SDH: Synchronous Digital Hierarchy SDH: Synchronous Digital Hierarchy SONET: Synchronous Optical Network SONET: Synchronous Optical Network SPE: Synchronous Payload Envelope SPE: Synchronous Payload Envelope STE: Section Terminating Entity STE: Section Terminating Entity STM: Synchronous Transport Module STM: Synchronous Transport Module STS: Synchronous Transport Signal STS: Synchronous Transport Signal TOH: Transport Overhead TOH: Transport Overhead VT: Virtual Tributary VT: Virtual Tributary

25 Slide 25 COMPANY CONFIDENTIAL NANOG, May Copyright © 1999, Juniper Networks, Inc. References Telcordia (Bellcore) GR-253-CORE Telcordia (Bellcore) GR-253-CORE ANSI T1.105 and T1.106 ANSI T1.105 and T1.106 ITU-T G.707 and G.783 ITU-T G.707 and G.783 SONET, Walter J. Goralski, McGraw-Hill Series on Computer Communications SONET, Walter J. Goralski, McGraw-Hill Series on Computer Communications RFC-1619 and Successor RFC-1619 and Successor update-04.txt update-04.txt

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