Tilak De Silva B Sc Eng M Sc
Tilak De Silva B. Sc. Eng, M. Sc. , C. Eng. , FIE(SL), FIEE(UK), FBCS(UK), CITP, MIEEE www. abcd. lk 10/27/2021 Issue 1 revision 1 Internal Use Only 1 of 36
Main Components of a Network • Access • Core 10/27/2021 Issue 1 revision 1 Internal Use Only 2 of 36
Main Components of a Network • Access • Aggregation • Core 10/27/2021 Issue 1 revision 1 Internal Use Only 3 of 36
Access Network 10/27/2021 Issue 1 revision 1 Internal Use Only 4 of 36
Core Network 10/27/2021 Issue 1 revision 1 Internal Use Only 5 of 36
Time Division Multiplexing (TDM) • PDH • SDH/SONET 10/27/2021 Issue 1 revision 1 Internal Use Only 6 of 36
Multi Protocol Label Switching (MPLS) 10/27/2021 Issue 1 revision 1 Internal Use Only 7 of 36
Core Network Structure Routers Multiplexers OLTEs + OF cables 10/27/2021 Issue 1 revision 1 Internal Use Only 8 of 36
Public Switched Telephone Network (PSTN) • • CPE – Telephone AGW – Exchange Access Network – Copper Wire Core Network – Transmission Links 10/27/2021 Issue 1 revision 1 Internal Use Only 9 of 36
AAA User RAS / NAS ISP Router MPLS PC Web Server Internet Modem DSLAM 10/27/2021 Issue 1 revision 1 AAA (RADIUS) SERVER Internal Use Only USER DB 10 of 36
Transmission Media • Copper – electrical signal • Fiber – optical signal • Radio – radio (electromagnetic) wave 10/27/2021 Issue 1 revision 1 Internal Use Only 11 of 36
Characteristics of Transmission Media Copper Fiber Radio High Attenuation Minimum losses Moderate losses Highly susceptible to noise & interference Minimum interference Moderate interference Low Bandwidth Higher Bandwidth Low Data rate Highest Data rate Higher Data rate Limited Distance Highest Distance Moderate Distance 10/27/2021 Issue 1 revision 1 Internal Use Only 12 of 36
Transmission Problems • • Attenuation Other Losses Noise Delay 10/27/2021 Issue 1 revision 1 Internal Use Only 13 of 36
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 10/27/2021 Issue 1 revision 1 Internal Use Only 14 of 36
Bandwidth of Transmission Media • Copper – from 0 to 1 GHz range • Radio – from 0 to 15 GHz range • Fiber – 100 THz range 10/27/2021 Issue 1 revision 1 Internal Use Only 15 of 36
Bandwidth vs. Bit rate = BW log 2 (1+S/N) • Voice – from 0 to 4 k. Hz • ADSL 2+ – from 25 k. Hz to 2. 2 MHz • G. SHDSL – from 0 up to 1 MHz 10/27/2021 Issue 1 revision 1 Internal Use Only 16 of 36
FDM vs. OFDM 10/27/2021 Issue 1 revision 1 Internal Use Only 17 of 36
Copper Cable Types • • Twisted Pair – UTP, STP / Cat 5, Cat 6 Drop Wires Multi Pair Coaxial 10/27/2021 Issue 1 revision 1 Internal Use Only 18 of 36
Radio Frequency Bands 10/27/2021 Issue 1 revision 1 Internal Use Only 19 of 36
Fiber Types • Single Mode • Multi Mode MM SM 10/27/2021 Issue 1 revision 1 Internal Use Only 20 of 36
Fiber Wavelength Bands 10/27/2021 Issue 1 revision 1 Internal Use Only 21 of 36
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. 10/27/2021 Issue 1 revision 1 Internal Use Only 22 of 36
Level and Ratio Measurements • The decibel (d. B) is a logarithmic unit used to express the ratio between two values. • Eg: If A=10, B=1000 B/A ratio = 10 log 10 (1000/10) d. B = 10 log 10 (100) d. B = 20 d. B 10/27/2021 Issue 1 revision 1 Internal Use Only 23 of 36
d. Bm • d. Bm is an abbreviation for the power ratio in decibels (d. B) of the measured power referenced to one milli. Watt (m. W). • Eg: If measured power is 100 m. W Power level in d. Bm = 10 log 10 (100/1) d. Bm = 10 log 10 (100) d. Bm = 20 d. Bm 10/27/2021 Issue 1 revision 1 Internal Use Only 24 of 36
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 (d. B) and optical power in d. Bms. 10/27/2021 Issue 1 revision 1 Internal Use Only 25 of 36
Link Budget of Fiber Optics 10/27/2021 Issue 1 revision 1 Internal Use Only 26 of 36
Link Budget Calculation Minimum Receiver Power = Attenuation + Splice Loss + Connector Loss + Tx Loss + Rx Loss + Margin 10/27/2021 Issue 1 revision 1 Internal Use Only 27 of 36
Splitters f Hal • 1: 2 Splitter // // Hal f • 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 log 10(0. 5) = 3 d. B • Practical loss is around 4 d. B 10/27/2021 Issue 1 revision 1 Internal Use Only 28 of 36
Splitter Ratios • 1: 2, 1: 4, 1: 8, 1: 16, 1: 32, 1: 64, 1: 128 Splitter Ratio 1: 2 1: 4 1: 8 1: 16 1: 32 Ideal Loss / Port (d. B) 3 6 9 12 15 Excess Loss (d. B, max) 1 1 2 3 4 Typical Loss (d. B) 4 7 11 15 19 10/27/2021 Issue 1 revision 1 Internal Use Only 29 of 36
PON Technology 10/27/2021 Issue 1 revision 1 Internal Use Only 30 of 36
FTTx Technologies 10/27/2021 Issue 1 revision 1 Internal Use Only 31 of 36
OSP Network • • • Telephone exchange MDF Cabinet DP Telephone 10/27/2021 Issue 1 revision 1 Internal Use Only 32 of 36
Wireless (Radio) Access Network • FDM/FDMA • FDD/TDD 10/27/2021 Issue 1 revision 1 Internal Use Only 33 of 36
Mobile Communication • 1 G - Basic Mobility, Basic Services, Incompatibility , 1980 • 2 G - Advanced Mobility [Roaming], More Services [Data Presence], Towards Global Solution • 3 G - Seamless Roaming, Service Concepts & Models, Global Radio Access, Global Solution • 4 G - IP based mobility, Very high data rates, Complete telecom/datacom convergence 10/27/2021 Issue 1 revision 1 Internal Use Only 34 of 36
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