CS490 Chapter 4a, Leon, Continued

1. CS490Chapter 4a, Leon, Continued Wavelength Division Multiplexing, Circuit Switches, POTS, A little about Telephone Signaling

2. The latest incarnation of FDM: Wavelength Division Multiplexing Optical MUX Optical deMUX 1 1 2 1 2 2. m Optical fiber m m To pick good wavelengths, look at Fig. 3.45, p 145. Figure 4.18

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

4. (a) WDM chain network c b d a (b) WDM ring network a Optical ADMs in a Fiber Optic Network 3 ADMs b c Figure 4.20

5. POTS consists of links and circuit switches 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

6. 1 2    N N-1 2 N  1 Crossbar Switch; Space-Division Switches Grows as N-squared Figure 4.22

7. Multistage switch. Grows as N to the 1.5 power 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

8. Time Division Switches 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 Usually called Time Slot Interchange Switch (TSI) Figure 4.25

9. 4.5 The Telephone Network: POTS or PSTN Setting up a circuit-switched path for the duration of the call. Figure 4.30

10. Telephone call set up. Note the three phase process that propagates through intermediate points Source Signal Go Ahead Signal Message Release Signal Destination This is an elaboration of the double timing diagram from Test 1. Figure 4.31

11. Routing for local and long-distance connections (a) Routing in a typical metropolitan area 4 C D 3 2 5 B A 1 Local Access and Transport Areas (b) Routing between two LATAs net 1 Uses LD Carrier nets net 2 LATA 1 LATA 2 Figure 4.32

12. POTS access transmission facilities Pedestal local telephone office Serving Area I/f distribution cable Distribution Frame Switch Serving Area I/f feeder cable Serving Area Interface Figure 4.33

13. Transmit pair Original signal Received signal Hybrid transformer Echoed signal Local Loop Receive pair 2 and 4 wire connections in the telephone network; echos. Hybrid is in the CO or Serving Area Interface Figure 4.34

14. 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

15. Digital cross connect and SONET ADM ADM ADM ADM Physical SONET Topology using ADMs and DCCs ADM ADM DCC Logical Topology Switches see this topology Figure 4.36

16. Basic Rate Interface (BRI): 2B+D Primary Rate Interface (PRI): 23B+D End to end digital services (ISDN) Circuit Switched Network Channel Switched Network Private BRI BRI Packet Switched Networks PRI PRI Signaling Network Figure 4.37

17. 4.6 A little about signaling in the POTS SPC Signaling Message Control Stored program control. A computer runs the switching at Cos. Figure 4.39

18. Common Channel Signaling Office A Office B Trunks Switch Switch Modem Modem Processor Processor Signaling Figure 4.39

19. SCP The signaling network is packet switched! 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

20. The Latest Incarnation: "The Intelligent Network" allows Caller ID, Conferencing, Etc. External Database Signaling Network Intelligent Peripheral SSP SSP Transport Network Figure 4.40

21. Many Lines Fewer Trunks Figure 4.43

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

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

24. (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

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

26. 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

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

28. Network Capacity Carried Load Offered Load Figure 4.50

29. 2 7 3 1 6 4 5 2 2 7 3 7 3 1 1 6 4 6 4 5 5 Figure 4.51

30. BSS BSS MSC SS#7 STP HLR VLR wireline terminal EIR PSTN AC MSC = mobile switching center PSTN = public switched telephone network STP = signal transfer point VLR = visitor location register AC = authentication center BSS = base station subsystem EIR = equipment identity register HLR = home location register Figure 4.52

31. CM CM MM MM RRM RRM RRM RRM SCCP SCCP MTP Level 3 MTP Level 3 MTP Level 2 MTP Level 2 LAPDm LAPDm LAPD LAPD 64 kbps 64 kbps 64 kbps 64 kbps radio radio Um Abis A mobile station base transceiver station base station controller MSC Figure 4.53

32. satellite motion (a) (b) Figure 4.54