Transmission Systems and the Telephone Network

1. Chapter 4 in Leon Skip in Chapter 3 Articles 3.8.7, 3.8.8 (polynomial math for CRC codes) I will ask you do to the long division in mod-2 arithmetic that we did last time Skip in Chapter 4 4.2.2 (SONET frame structure) 4.6 Signaling in POTS Transmission Systems and the Telephone Network

2. Sharing of an expensive channel by multiplexing (MUX) (a) (b) A A A A Trunk group B B B MUX MUX B C C C C Figure 4.1

3. Frequency Division MUX (FDM) A f W 0 B f 0 W C B A f C f 0 W (a) Individual signals occupy W Hz (b) Combined signal fits into channel bandwidth Figure 4.2

4. (a) Each signal transmits 1 unit every 3T seconds Time Division MUX (TDM) A1 A2 t 0T 6T 3T B1 B2 t 6T 3T 0T C1 C2 t 0T 6T 3T 0T 1T 2T 3T 4T 5T 6T A2 B2 B1 C1 C2 A1 t (b) Combined signal transmits 1 unit every T seconds Figure 4.3

5. Standard T1 Carrier (TDM of 24 PCM voice channels) 1 1 2 MUX MUX 2 . . . . . . 22 23 24 1 b 24 2 b . . . frame 24 24 (1+24channels*8bits/channel)*8000 frames/sec = 1.544 Mbps Figure 4.4

6. Primary Multiplex Eg. Digital Switch 24 chan PCM M23 Multiplex x7 M12 Multiplex x4 DS2 6.312 Mbps DS3 44.736 Mbps DS1 1.544 Mbps 1 M13 Multiplex DS3 44.736 Mbps    28 CEPT 1 Primary Multiplex Eg. Digital Switch 30 chan PCM 3rd order Multiplex x4 CEPT 4 2nd order Multiplex x4 4th order Multiplex x4 34.368 Mbps 8.448 Mbps 2.048 Mbps 139.264 Mbps North American Digital Hierarchy European Digital Hierarchy Figure 4.5

7. t 5 4 3 2 1 5 4 3 2 1 Figure 4.6

8. Figure 4.7 (Optical fiber network for long distance carrier in 1998) could not be reproduced well enough for inclusion.

9. DS1 Low-Speed Mapping Function DS2 STS-1 CEPT-1 51.84 Mbps DS3 Medium Speed Mapping Function STS-1 44.736       OC-n STS-n STS-3c STS-1 Mux E/O Scrambler CEPT-4 High- Speed Mapping Function STS-1 STS-1 139.264 STS-3c STS-1 STS-1 High- Speed Mapping Function ATM STS-1 150 Mbps Figure 4.8

10. DEMUX DEMUX MUX MUX (a) pre-SONET multiplexing insert tributary remove tributary (b) SONET Add-Drop multiplexing ADM DEMUX MUX insert tributary remove tributary Figure 4.9

11. a OC-3n OC-3n b 3 ADMs c OC-3n physical loop net Figure 4.10

12. a a OC-3n OC-3n b c b c OC-3n logical fully-connected net 3 ADMs connected in physical ring topology (b) (a) Figure 4.11

13. a a b b d d c c (a) Dual ring (b) Loop-around in response to fault Figure 4.12

14. Regional Ring Metro Ring Inter-Office Rings Figure 4.13

15. STS PTE STS PTE LTE LTE SONET Terminal SONET Terminal STE STE STE Mux Mux reg reg reg Section Section STS Line STS-1 Path path path line line line line section section section section section section section optical optical optical optical optical optical optical (a) STE: Section Terminating Equipment, e.g. a repeater LTE: Line Terminating Equipment, e.g. a STS-1 to STS-3 multiplexer PTE: Path Terminating Equipment, e.g. an STS-1 multiplexer (b) Figure 4.14

16. 90 bytes 87B B B B Section Overhead 3rows Information Payload 9 Rows Line Overhead 6rows 125 s Transport overhead Figure 4.15

17. first octet Pointer frame k 87 columns Synchronous Payload Envelope 9 rows Pointer last octet frame k+1 first column is path overhead Figure 4.16

18. Byte Interleave STS-1 STS-1 STS-1 STS-1 Map STS-3 STS-1 STS-1 STS-1 STS-1 Map STS-1 STS-1 STS-1 STS-1 Map Incoming STS-1 Frames Synchronized New STS-1 Frames Figure 4.17

19. Optical MUX Optical deMUX 1 1 2 1 2 2. m Optical fiber m m Figure 4.18

20. Figure 4.19 (Optical signal in a WDM system) could not be reproduced well enough for inclusion. Figure 4.19

21. (a) WDM chain network c b d a (b) WDM ring network a 3 ADMs b c Figure 4.20

22. Control 1 1 2 2 Connection of inputs to outputs 3 3       N N (a) Network Link Switch User n User n-1 User 1 (b) Switch Figure 4.21

23. 1 2    N N-1 2 N  1 Figure 4.22

24. 2(N/n)nk + k (N/n)2 crosspoints kxn nxk N/n x N/n 1 1 1 kxn nxk N inputs 2 2 N outputs N/n x N/n kxn nxk 2 3 3          kxn nxk N/n N/n N/n x N/n k Figure 4.23

25. kxn nxk N/n x N/n 1 1 1       n-1 busy Desired input Desired output N/n x N/n n-1 nxk kxn j n-1 busy m N/n x N/n n+1       N/n x N/n 2n-2 nxk kxn N/n x N/n N/n free path free path N/n 2n-1 Figure 4.24

26. 1 From TDM DeMUX 2 24    24 1 23 2    Read slots in permuted order 2 1 24 23       1 To TDM MUX 2 24 Figure 4.25

27. input TDM frame with n slots 2 1 n       output TDM frame with k slots kxn nxk N/n x N/n 1 1 1 nxk N inputs 2 nxk 3    nxk N/n Figure 4.26

28. first slot first slot kxn nxk N/n x N/n 1 1 1 kxn nxk 2 2 N/n x N/n 2       kxn nxk N/n N/n N/n x N/n kth slot kth slot k Figure 4.27

29. Space Stage TSI Stage TSI Stage kxn TDM n slots nxk TDM k slots TDM k slots 1 1 kxn nxk n slots N/n x N/n Time-Shared Space Switch 2 2 N outputs N inputs kxn nxk n slots 3 3       n slots kxn nxk N/n N/n Figure 4.28

30. B2 A2 B1 A1 A1 C1 B1 A1 A1 C1 3x2 2x3 1 1 D1 D1 B1 B1 3x2 D2 C2 D1 C1 C1 D1 2x3 2 2 Figure 4.29

31. Figure 4.30

32. Source Signal Go Ahead Signal Message Release Signal Destination Figure 4.31

33. (a) Routing in a typical metropolitan area 4 C D 3 2 5 B A 1 (b) Routing between two LATAs net 1 net 2 LATA 1 LATA 2 Figure 4.32

34. Pedestal local telephone office Serving Area I/f distribution cable Distribution Frame Switch Serving Area I/f feeder cable Figure 4.33

35. Transmit pair Original signal Received signal Hybrid transformer Echoed signal Receive pair Figure 4.34

36. Digital cross-connect System Channel-switched traffic (digital leased lines) Local analog Tie lines Foreign exchange Local digital Local Switch Digital trunks Circuit-switched traffic Figure 4.35

37. ADM ADM ADM ADM Physical SONET Topology using ADMs and DCCs ADM ADM DCC Logical Topology Switches see this topology Figure 4.36

38. Basic Rate Interface (BRI): 2B+D Primary Rate Interface (PRI): 23B+D Circuit Switched Network Channel Switched Network Private BRI BRI Packet Switched Networks PRI PRI Signaling Network Figure 4.37

39. SPC Signaling Message Control Figure 4.39

40. Office A Office B Trunks Switch Switch Modem Modem Processor Processor Signaling Figure 4.39

41. SCP STP STP STP STP SSP SSP Signaling Network Transport Network SSP = Service switching point (signal to message) STP = Signal transfer point (message transfer) SCP = Service control point (processing) Figure 4.40

42. External Database Signaling Network Intelligent Peripheral SSP SSP Transport Network Figure 4.40

43. Application Layer Presentation Layer TUP TCAP ISUP Session Layer SCCP Transport Layer Network Layer MTP Level 3 Data Link Layer MTP Level 2 Physical Layer MTP Level 1 Figure 4.42

44. Many Lines Fewer Trunks Figure 4.43

45. N(t) all trunks busy t 1 2 trunk # 3 4 5 6 7 Figure 4.44

46. # trunks Blocking Probability 10 9 8 7 1 6 2 3 4 5 offered load Figure 4.45

47. (a) A D B E C F Trunk group (b) Tandem Switch 2 Tandem Switch 1 F E C D B A 10 Erlangs between each pair 90 Erlangs Figure 4.46

48. Switch Switch Tandem Switch Alternate Route High Usage Route Figure 4.47

49. Tandem Switch 2 Tandem Switch 1 Alternate Routes for B-E, C-F Switch D Switch A Switch E Switch B High Usage Route B-E Switch C Switch F High Usage Route C-F Figure 4.48

50. Tandem Switch 3 Tandem Switch 2 Tandem Switch 1 Alternate Routes Switch B Switch A High Usage Route Figure 4.49