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

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. AAA User MPLS Internet Web Server 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
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

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

29. Splitter Ratios 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128 Splitter Ratio
Ideal Loss / Port (dB) 3 6 9 12 15
Excess Loss (dB, max) 1 2 4
Typical Loss (dB) 7 11 19

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