1. Computer Networks Farzad Rojan Chapter 2: Physical Layer

2. Computer Networks – Chapter 2 Introduction Transmission Media Wireless Transmission Communication Satellites Public Switched Telephone Network Mobile Network

3. Introduction Computer Networks – Chapter 2 Fourier Analysis

4. Introduction Computer Networks – Chapter 2 Bandwidth-Limited Signals

5. Transmission Media Computer Networks – Chapter 2 Magnetic Media  How cheap? How fast? Twisted pair cable  CAT-3, CAT-5, CAT-5e, CAT-6  UTP and STP (a) Category 3 UTP (b) Category 5 UTP.

6. Transmission Media Computer Networks – Chapter 2 Coaxial Cable  Wideband and long distance  Multi-band transmission  Two way transmission by split band

7. Transmission Media Computer Networks – Chapter 2 Fiber optics  Ultra Wideband and long distance  Multi-band transmission by wave-length division multiplexing  Up to Terra bps  No electromagnetic interfrence.

8. Transmission Media Computer Networks – Chapter 2 Transmission of light in fiber optics

9. Transmission Media Computer Networks – Chapter 2 Fiber cables  Multi mode  Single mode

10. Transmission Media Computer Networks – Chapter 2 Light Sources  LED  Semiconductor Laser

11. Transmission Media Computer Networks – Chapter 2 Comparison of fiber and copper  Distace 5 km vs. 50 km  Crosstalk  Weight 8000 kg vs. 100 kg per km  Capacity low vs. ultra high  Electrical interface cheap vs. expensive

12. Wireless Transmission Computer Networks – Chapter 2 Wireless communication  Electromagnetic spectrum

13. Computer Networks – Chapter 2 Wireless communication  Radio transmission Wireless Transmission

14. Computer Networks – Chapter 2 Wireless communication bands  Industrial, scientific and medical bands (ISM) Unlicenced bands (low power) Wireless Transmission

15. Computer Networks – Chapter 2 Communication satellites Communication Satellites

16. Computer Networks – Chapter 2 Satellites bands Transponders: low noise receivers high power transmitters about 80 MHz bandwidth Communication Satellites

17. Computer Networks – Chapter 2 VSAT  1m diameter antenna  19.2 kbps Communication Satellites

18. Computer Networks – Chapter 2 Iridium (LEO)  66 satellites (element 77 is iridium)  Moving cells Communication Satellites

19. Computer Networks – Chapter 2 Globalstar  48 satellites at 750 km  Ground station switching Communication Satellites

20. Computer Networks – Chapter 2 Teledesic  30 satellites at 1350 km  100 Mbps up- and 720 Mbps downlink internet  Planned for year 2005 Communication Satellites

21. Public Switched Telephone Network Computer Networks – Chapter 2 Public switched telephone network  Spread out of the world  Modems are used for data transfer  The cheapest for access network Structure of telephone network

22. Computer Networks – Chapter 2 New circuit routing in telephone network Local loops  Wired or wireless  Digital or analog Public Switched Telephone Network

23. Computer Networks – Chapter 2 Local loops  Wired or wireless  Digital or analog Public Switched Telephone Network

24. Computer Networks – Chapter 2 Digital subscriber lines (XDSL)  HDSL, VDSL and ADSL Public Switched Telephone Network

25. Computer Networks – Chapter 2 Asymmetric Digital subscriber lines (ADSL)  Discrete Multi Tone (DMT)  ANSI T1.413 Allow (8/1 Mbps)  Standard service (512/64 kbps)  Premium service (1000/256 kbps) Public Switched Telephone Network

26. Computer Networks – Chapter 2 ADSL equipments Public Switched Telephone Network

27. Computer Networks – Chapter 2 FDM Public Switched Telephone Network

28. Computer Networks – Chapter 2 WDM Public Switched Telephone Network

29. Computer Networks – Chapter 2 TDM  Digital trunk T1 and Multiplexing Public Switched Telephone Network

30. Computer Networks – Chapter 2 TDM  Digital trunk T1 and Multiplexing Public Switched Telephone Network

31. Computer Networks – Chapter 2 TDM  CCITT Digital trunk E1 and Hierarchy E1: 32×64 kbps=2.048 Mbps E2: 4E1 =8.848 Mbps E3: 4E2 =34.304 Mbps E4: 4E3 =139. 264 Mbps E5: 4E4 =565.148 Mbps Public Switched Telephone Network

32. Computer Networks – Chapter 2 SONET/SDH  Synchronous optical network Different carriers internetwork Support international internetworking Multiplexing more channels Operation, administration and maintenance (OAM) Public Switched Telephone Network

33. Computer Networks – Chapter 2 SONET frame  Basic frame are repeated every 125 µsec  Basic frame contains 810 bytes Public Switched Telephone Network

34. Computer Networks – Chapter 2 SONET and SDH trunk hierarchy Public Switched Telephone Network

35. Computer Networks – Chapter 2 Switching Circuit switching Message switching Packet switching

36. Computer Networks – Chapter 2 Public Switched Telephone Network

37. Mobile Network Computer Networks – Chapter 2 1 st generation: analog voice 2 nd generation: digital voice, SMS and data 3 rd generation: digital voice and data