Chapter 4 Circuit-Switching Networks

1. Chapter 4Circuit-Switching Networks Chapter Figures

2. (a) (b) A A A A B B MUX MUX B B C C C C Figure 4.1 Communication Networks

3. (a) B A f f 0 Wu C C 0 Wu (b) B A f f 0 W Wu 0 Figure 4.2 Communication Networks

4. A1 A2 … t 0T 6T 3T B1 B2 … t 6T 3T 0T C1 C2 … t 0T 6T 3T (b) C2 A2 B2 … A1 C1 B1 t 0T 1T 2T 3T 4T 5T 6T (a) Figure 4.3 Communication Networks

5. 1 1 2 MUX 2 MUX . . . . . . 22 23 24 b 24 2 1 b . . . Frame 24 24 Figure 4.4 Communication Networks

6. North American digital hierarchy Primary multiplex e.g., digital switch 24 channel PCM M23 Multiplex x7 M12 Multiplex x4 DS2 6.312 Mbps DS3 44.736 Mbps DS1 1.544 Mbps . . . M13 Multiplex x28 DS3 44.736 Mbps . . . European digital hierarchy CEPT 1 Primary multiplex e.g., digital switch 30 channel PCM CEPT 4 3rd order multiplex x4 2nd order multiplex x4 4th order multiplex x4 34.368 Mbps 2.048 Mbps 8.448 Mbps 139.264 Mbps Figure 4.5 Communication Networks

7. MUX t 5 4 3 2 1 5 4 3 2 1 Figure 4.6 Communication Networks

8. Optical deMUX Optical MUX 1 1 2 1 2 2. m Optical fiber m m Figure 4.7 Communication Networks

9. Figure 4.8 Communication Networks

10. Figure 4.9 Communication Networks

11. DS1 Low-speed mapping function DS2 STS-1 CEPT-1 51.84 Mbps Medium speed mapping function DS3 STS-1 44.736 . . . . . . STS-3c OC-n STS-n STS-1 STS-1 High- speed mapping function MUX CEPT-4 STS-1 STS-1 Scrambler E/O STS-1 STS-1 139.264 STS-3c High- speed mapping function ATM or POS Figure 4.10 Communication Networks

12. (a) PTE PTE LTE LTE SONET terminal SONET terminal STE STE STE MUX MUX Reg Reg Reg Section Section STS Line STS-1 Path STE = Section Terminating Equipment, for example, a repeater/regenerator LTE = Line Terminating Equipment, for example, a STS-1 to STS-3 multiplexer PTE = Path Terminating Equipment, for example, an STS-1 multiplexer (b) Path Path Line Line Line Line Section Section Section Section Section Section Section Optical Optical Optical Optical Optical Optical Optical Figure 4.11 Communication Networks

13. 90 bytes A1 A2 87B Section overhead 3rows B1 H1 H2 H3 9 rows B2 K1 K2 Line overhead 6rows 125 s Transport overhead Information payload Figure 4.12 Communication Networks

14. First octet Pointer Frame k 87 Columns Synchronous payload envelope 9 Rows Last octet Pointer Frame k+1 First column is path overhead Figure 4.13 Communication Networks

15. Frame k Pointer Pointer First octet of SPE First octet of SPE Stuff byte Stuff byte Frame k + 1 Pointer Pointer First octet of SPE First octet of SPE (a) Negative byte stuffing (b) Positive byte stuffing Frame k Frame k + 1 Figure 4.14 Communication Networks

16. STS-1 STS-1 STS-1 STS-1 Map Byte Interleave 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 4.15 Communication Networks

17. Telephone Switch Telephone Switch Telephone Switch Router Router Router Transport Network Figure 4.16 Communication Networks

18. (a) Pre-SONET multiplexing MUX MUX DEMUX DEMUX Insert tributary Remove tributary (b) SONET add-drop multiplexing MUX DEMUX ADM Insert tributary Remove tributary Figure 4.17 Communication Networks

19. (a) 1 2 4 3 (b) 2 3 1 4 Figure 4.18 Communication Networks

20. W T R Bridge Selector R T P T = Transmitter W = Working line R = Receiver P = Protection line Figure 4.19 Communication Networks

21. Switch Switch W R T APS signaling T R P T = Transmitter W = Working line R = Receiver P = Protection line Figure 4.20 Communication Networks

22. Switch Switch W 1 T R W ² T R … … … … W … n T R P T R APS signaling T = Transmitter W = Working line R = Receiver P = Protection line Figure 4.21 Communication Networks

23. a OC-3n OC-3n b STS-n STS-n c OC-3n Physical ring topology Figure 4.22 Communication Networks

24. (a) (b) a a OC-3n OC-3n b c b c OC-3n Logical fully connected topology Three ADMs connected in physical ring topology Figure 4.23 Communication Networks

25. 1 W 2 4 P 3 W = Working line P = Protection line Figure 4.24 Communication Networks

26. 1 W 2 4 P 3 W = Working line P = Protection line Figure 4.25 Communication Networks

27. 1 Equal delay W P 2 4 Spatial Reuse 3 Figure4.26 Communication Networks

28. 1 W Equal delay P 2 4 Fault on working links 3 Figure 4.27 Communication Networks

29. 1 W Equal delay P 2 4 Fault on working and protection links 3 Figure 4.28 Communication Networks

30. Regional ring Metro ring Interoffice rings Figure 4.29 Communication Networks

31. B A C D Router Router Router Router F G E Figure 4.30 Communication Networks

32. c b d a a 3 ADMs b c (a) WDM chain network (b) WDM ring network Figure 4.31 Communication Networks

33. … … Optical fiber switch … … DeMUX MUX Output Input … WDM WDM … Wavelength cross-connect … WDM … WDM … Dropped wavelengths Added wavelengths Figure 4.32 Communication Networks

34. (b) (a) Control 1 1 2 2 3 3 Connection of inputs to outputs … … Link Switch N User n N User n – 1 User 1 Figure 4.33 Communication Networks

35. 1 2 … N … N –1 2 N 1 Figure 4.34 Communication Networks

36. 2(N/n)nk + k (N/n)2 crosspoints kn nk N/n N/n 1 1 1 kn nk 2 N outputs N inputs 2 N/n N/n 2 kn nk 3 3 … … … kn nk N/n N/n N/n N/n k Figure 4.35 Communication Networks

37. kxn nxk N/n x N/n 1 1 1 … … n-1 busy N/n x N/n Desired output Desired input kxn nxk n-1 j m n-1 busy 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 4.36 Communication Networks

38. a 1 Read slots according to connection permutation 2 b 3 … … d b c b a a d c    24 2 1 24 2 1 23 23 Write slots in order of arrival 22 23 c 24 d Time-slot interchange Figure 4.37 Communication Networks

39. kxn nxk N/n x N/n 1 1 1 nxk N inputs 2 Input TDM frame with n slots Output TDM frame with k slots nxk 1 3 2 …    n … 2 1 k … 2 1 n nxk N/n Time-slot interchange Figure 4.38 Communication Networks

40. First slot First slot N/n N/n k n n k 1 1 1 k n n k 2 2 N/nN/n 2 … … … k n n k N/n N/n N/n N/n kth slot kth slot k Figure 4.39 Communication Networks

41. Space stage TSI stage TSI stage kxn TDM n slots TDM k slots nxk TDM k slots 1 1 kxn nxk n slots N/n x N/n Time-shared space switch N outputs 2 N inputs 2 kxn nxk n slots 3 3 … … n slots kxn nxk N/n N/n Figure 4.40 Communication Networks

42. (a) A C B A D C D B B2 A2 B1 A1 (b) A1 C1 B1 A1 C1 A1 3x2 2x3 1 1 D1 D1 B1 B1 3x2 D2 C2 D1 C1 D1 C1 2x3 2 2 Figure 4.41 Communication Networks

43. Figure 4.42 Communication Networks

44. Source Signal Go ahead Signal Message Release Signal Destination Figure 4.43 Communication Networks

45. (a) 4 C D 3 2 5 B A 1 (b) Net 1 Net 2 LATA 1 LATA 2 Figure 4.44 Communication Networks

46. Pedestal Serving area interface Local telephone office Distribution cable Distribution frame Switch Serving area interface Feeder cable Figure 4.45 Communication Networks

47. Transmit pair Original signal Received signal Hybrid transformer Echoed signal Receive pair Figure 4.46 Communication Networks

48. 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 4.47 Communication Networks

49. ADM (a) ADM ADM ADM DCC ADM ADM (b) Figure 4.48 Communication Networks

50. Circuit- switched network Private channel- switched network BRI BRI Packet- switched networks PRI PRI Signaling network Basic rate interface (BRI): 2B+D Primary rate interface (PRI): 23B+D Figure 4.49 Communication Networks