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General

General. Tilak De Silva B. Sc.Eng , M.Sc., C.Eng. , FIE(SL), FIEE(UK), FBCS(UK), CITP, MIEEE www.abcd.lk. Main Components of a Network. Access Core. Main Components of a Network. Access Aggregation Core. Access Network. Core Network. Time Division Multiplexing (TDM). PDH

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General

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  1. General Tilak De Silva B. Sc.Eng, M.Sc., C.Eng., FIE(SL), FIEE(UK), FBCS(UK), CITP, MIEEE www.abcd.lk

  2. Main Components of a Network • Access • Core

  3. Main Components of a Network • Access • Aggregation • Core

  4. Access Network

  5. Core Network

  6. Time Division Multiplexing (TDM) • PDH • SDH/SONET

  7. Multi Protocol Label Switching (MPLS)

  8. Core Network Structure Routers Multiplexers OLTEs + OF cables

  9. Public Switched Telephone Network (PSTN) • CPE – Telephone • AGW – Exchange • Access Network – Copper Wire • Core Network – Transmission Links

  10. MPLS Internet AAA Web Server User ISP Router RAS / NAS Modem PC DSLAM AAA (RADIUS) SERVER USER DB

  11. Transmission Media • Copper – electrical signal • Fiber – optical signal • Radio – radio (electromagnetic) wave

  12. Characteristics of Transmission Media

  13. Transmission Problems • Attenuation • Other Losses • Noise • Delay

  14. Quality of a Signal • Signal to Noise Ratio (SNR) • Bit Error Rate (BER) BER is the number of bit errors divided by the total number of transferred bits during a studied time interval

  15. Bandwidth of Transmission Media • Copper – from 0 to 1 GHz range • Radio – from 0 to 15 GHz range • Fiber – 100 THz range

  16. Bandwidth vs. Bit rate Bit rate = BW log2 (1+S/N) • Voice – from 0 to 4 kHz • ADSL2+ – from 25 kHz to 2.2 MHz • G.SHDSL – from 0 up to 1 MHz

  17. FDM vs. OFDM

  18. Copper Cable Types • Twisted Pair – UTP, STP / Cat5, Cat6 • Drop Wires • Multi Pair • Coaxial

  19. Radio Frequency Bands

  20. Fiber Types • Single Mode • Multi Mode MM SM

  21. Fiber Wavelength Bands

  22. Wavelength Division Multiplexing (WDM) • WDM is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e. colors) of laser light.

  23. Level and Ratio Measurements • The decibel (dB) is a logarithmic unit used to express the ratio between two values. • Eg: If A=10, B=1000 B/A ratio = 10 log10 (1000/10) dB = 10 log10 (100) dB = 20 dB

  24. dBm • dBm is an abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milliWatt (mW). • Eg: If measured power is 100 mW Power level in dBm = 10 log10 (100/1) dBm = 10 log10 (100) dBm = 20 dBm

  25. Link Budget of Fiber Optics • The link budget of fiber optic communication link is the allocation of available optical power (launched into a given fiber by a given source) among various loss-producing mechanisms such as launch coupling loss, fiber attenuation, splice losses, and connector losses, in order to ensure that adequate signal strength (optical power) is available at the receiver. • In link budget, attenuation is specified in decibels (dB) and optical power in dBms.

  26. Link Budget of Fiber Optics

  27. Link Budget Calculation Minimum Receiver Power = Attenuation + Splice Loss + Connector Loss + Tx Loss + Rx Loss + Margin

  28. Splitters • 1:2 Splitter • Every time the signal is split two ways, half the power goes one way and half goes the other. • So each direction gets half the power, or the signal is reduced by, 10 log10(0.5) = 3 dB • Practical loss is around 4 dB Half // // Half

  29. Splitter Ratios • 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128

  30. PON Technology

  31. FTTx Technologies

  32. OSP Network • Telephone exchange • MDF • Cabinet • DP • Telephone

  33. Wireless (Radio) Access Network • FDM/FDMA • FDD/TDD

  34. Mobile Communication • 1G - Basic Mobility, Basic Services, Incompatibility , 1980 • 2G - Advanced Mobility [Roaming], More Services [Data Presence], Towards Global Solution • 3G - Seamless Roaming, Service Concepts & Models, Global Radio Access, Global Solution • 4G - IP based mobility, Very high data rates, Complete telecom/datacom convergence

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