1. Chapter Objectives After completing this chapter you will be able to: Describe the various PDH standards Describe the operation and the frame format, of PDH systems Describe the SONET standard under the following headings: frame structure, overheads, pointers, multiplexing and the network Describe the SDH standard under the following headings: frame structure, payload capacity, multiplexing and equipment

2. Europe and North American PDH Systems

3. Digital Hierarchy Levels

4. PDH Multiplexing

5. Disadvantages of PDH  Inflexible and expensive  Limited management and maintenance capabilities  Costly AO&M  Low capacity  Network status verification problems  Network failure  High capacity growth  Access network problems  Vendor incompatibility

6. FASTB 1..4 JS JB 12341234 Basic Frame Structure of Plesiochronous Digital Signals

7. PDH/SDH and SONET

8. SONET Hierarchy

9. STS-1 Frame Format BBB87 B Transport Overhead Synchronous Payload Envelope (SPE) (B = 8 Bit Byte)

10. STS-1 Frame Elements 87 Columns 90 Columns 9 Rows Synchronous Payload Envelope Transport Overhead

11. STS-1 87 Columns 9 Rows STS-1 Payload Capacity 1305987 STS POH (9 Bytes) Fixed Stuff

12. STS-1 SPE 90 Columns 9 Rows 125  s STS-1 SPE 250  s Transport Overhead STS-1 POH Column Start of STS-1 SPE J1

13. N x 90 Columns Transport Overhead STS-N Envelope Capacity (B = 8 Bit Byte) STS-N 125  s 9 Rows

14. Overhead Layers ADM or DCS ADM or DCS REG PTE Section Line Path Termination Section Termination Line Termination Section Termination Path Termination Service (DS1, DS3..) Mapping and Demapping Service Mapping and Demapping PTE Path Terminating Element REG Regenerator ADM Add-Drop Multiplexer DCS Digital Cross-Connect System

15. Section Overhead A1 B1 H1 D1 B2 D4 D7 D10 S1Z1 1 2 3 4 5 6 7 8 9 A2 E1 H2 D2 K1 D5 D8 D11 M0 or M1/Z2 JO/ZO F1 H3 D3 K2 D6 D9 D12 E2 J1 B3 H4 C2 G1 F2 Z3 Z4 Z5 Transport Overhead Path Overhead Section Overhead Line Overhead 1 3 2

16. Line Overhead A1 B1 H1 D1 B2 D4 D7 D10 S1Z1 1 2 3 4 5 6 7 8 9 A2 E1 H2 D2 K1 D5 D8 D11 M0 or M1/Z2 JO/ZO F1 H3 D3 K2 D6 D9 D12 E2 J1 B3 H4 C2 G1 F2 Z3 Z4 Z5 Transport Overhead Path Overhead Section Overhead Line Overhead 1 3 2

17. Path Overhead A1 B1 H1 D1 B2 D4 D7 D10 S1Z1 1 2 3 4 5 6 7 8 9 A2 E1 H2 D2 K1 D5 D8 D11 M0 or M1/Z2 JO/ZO F1 H3 D3 K2 D6 D9 D12 E2 J1 B3 H4 C2 G1 F2 Z3 Z4 Z5 Transport Overhead Path Overhead Section Overhead Line Overhead 1 3 2

18. 12345678 BIP-2REI-VRFI-V Signal Label RDI-V RFI-V VT Path Remote Failure Indication REI-V VT Path Remote Error Indication RDI-V VT Path Remote Defect Indication VT POH

19. Pointer 90 Columns 9 Rows 125  s STS-1 SPE 250  s Transport Overhead STS-1 POH Column Start of STS-1 SPE J1 H1 H2

20. VT Superframe and Envelope Capacity V1 V2 V3 V4 125  s 250  s 375  s 500  s VT1.5VT2VT3VT6 26107 3553 26107 3553 26107 3553 26107 3553 104140212428 VT Envelope Capacity Mulitframe Indicator H4 of previous STS-1 SPE X = undefined bit XXXXXX00 XXXXXX01 XXXXXX10 XXXXXX11 VT Envelope Capacity Bytes/Superframe

21. VT SPE and Payload Capacity V1 V2 V3 V4 V5 J2 J6 J7 125  s 250  s 375  s 500  s VT1.5VT2VT3VT6 25106 3452 25106 3452 25106 3452 25106 3452 100136208424 VT Superframe VT SPE VT Payload Capacity Bytes/VT SPE

22. Mulitplexing Hierarchy VT-1.5 VT-2 VT-6 OC-48 STS-12 STS-1 STS-3 SPE SPE3c VT Group OC-12 OC-3 OC-1 6 Mbit/s 2 Mbit/s 1.5 Mbit/s 45 Mbit/s 140 Mbit/s 2.5 Gbit/s 52 Mbit/s 622Mbit/s 155Mbit/s x 4 x 3 x 4 x 3

23. Network Configurations Point-to-multipoint Point-to-point Hub Network

24. SONET/SDH Hierarchies

25. SDH Frame Structure 270 Columns 9 Columns of Overheads 1 2 3 4 5 6 8 7 9 9 Rows 125 Microseconds 1 23476589 Each box = 1 byte equivalent to 64 kbit/s capacity SOH Pointer SOH 261 Columns of Payload

26. SDH Bit Rates

27. Pointer SOH STM-1 VC-4 C-4 260 9 POHPOH 140 Mbit/sC-4VC-4 STM-1 SDH Multiplexing Structure

28. x 1 x 3 x 1 x 7 x 3 x 1x N STM-NAUG AU4 VC4 C4 C3 C2 C12 C11 139,264 kbit/s 44,736 34,368 kbit/s 6,312 kbit/s 2,048 kbit/s 1,544 kbit/s VC3 VC2 VC12 VC11 TU3 TU2 TU12 TUG2 TUG3 Aligning Mapping Multiplexing STM Synchronous Transport Mode AUG Administrative Unit Group AU Administrative Unit TUG Tributary Unit Group TU Tributary Unit VC Virtual Container C Container

29. West East 155 Mbit/s Carries 63 x 2 Mbit/s 155 Mbit/s Add-Drop Direct Add-Drop Multiplexer Up to 63 x 2 Mbit/s Tributaries or other rates