1. COMMUNICATIONS SERVICE PROVIDER
NETWORKS
FEBRUARY 2013
By Eng. Anuradha Udunuwara,
BSc.Eng(Hons), CEng, MIE(SL), MEF-CECP, MBCS, ITILv3 Foundation, MIEEE, MIEEE-CS, MIEE, MIET, MCS(SL), MSLAAS

2. Agenda
2
 Introduction
 Domestic Networks
 Wire-line networks
 Wireless networks
 International networks
 NGN
 Transformation
(c) Anuradha Udunuwara

3. INTRODUCTION

4. Why a network?
4
CSP Network Subscriber/
services customer/
user
Customers don’t buy networks
(c) Anuradha Udunuwara

5. The network lifecycle
5
Strategy & Planning & Projects & Operations &
Architecture Designing Implementation Maintenance
(c) Anuradha Udunuwara

6. Categorization Wired (optical fiber) APON
BPON
Core
Wireless
Wired (optical fiber)
Aggregation TDM PON
Wireless GPON
PON
Cable WDM PON EPON
CSP
networks Wired
Optical Hybrid
fiber PON
10GPON
Access AON
Narrow
Band
Copper ADSL/2/2+ 10GEPON
Broadband
VDSL/2
Media Wireless WLAN
WPAN
2G
WMAN Cellular 3G
(c) Anuradha Udunuwara
WWAN Satellite 64G

7. DOMESTIC NETWORKS
Wire-Line
Wireless

8. WIRE-LINE NETWORKS

9. Original PSTN
9
UTP UTP
• Manual switching directly connected two local loops
• Due to microphone technology, audio BW was 4 kHz
• PSTN is the network
(c) Anuradha Udunuwara
• POTS is the service

10. Analog switched PSTN
10 CO CO
Local loop Telephone Local loop
(analog) network (analog)
(analog)
• Invention of tube amplifier enabled long distance
• Between central offices used FDM spaced at 4 kHz (each cable carrying 1 group
= 12 channels)
(c) Anuradha Udunuwara

11. PSTN Hierarchy
11
Source : http://hyperlinesystems.com/info/fund_telecom/index.php?id=2
(c) Anuradha Udunuwara

12. Data support via voice-grade modems
12
• To send data, it is converted into 4 kHz audio (modem)
• Data rate is determined by Shannon's capacity theorem (there is a maximum data rate (bps) called the
"capacity”, that can be reliably sent through the communications channel. The capacity depends on the BW
and SNR)
(c) Anuradha Udunuwara

13. 13
Source: http://www.cse.wustl.edu/~jain/cse473-05/ftp/i_3phy/sld025.htm
(c) Anuradha Udunuwara

14. Digital PSTN
14
Source : http://kingdominique.be/notepro/nyquist-theorem
(c) Anuradha Udunuwara

15. Digital PSTN, Cont.,
15
CO SWITCH
“last mile”
TDM
PSTN digital
“last mile” TDM
Subscriber Line
analog CO SWITCH
LP filter to 4 kHz at input to CO switch (before A/D)
(c) Anuradha Udunuwara

16. Digital PSTN, Cont.,
16
 Sample 4 kHz audio at 8 kHz (Nyquist)
 Need 8 bits per sample = 64 kbps
 Multiplexing 64 kbps channels leads to higher and higher
rates
 Only the subscriber line (local loop) remains analog (too
expensive to replace)
(c) Anuradha Udunuwara

17. Transmission and Switching
17
Switching
Transmission
Source: http://www.telecommunications-tutorials.com/tutorial-PSTN.htm
(c) Anuradha Udunuwara

18. Digital Local Loop Technologies
18
 ISDN
 Voice and Data
 Longer distance
 DSL
 Higher speed
 Several variants
 Different encoding technologies -> different data
transmission rates
(c) Anuradha Udunuwara

19. xDSL flavors
19
Source : http://wiki.ftthcouncil.eu/index.php?title=File:Dsl-distance-chart.png&filetimestamp=20100413150655
(c) Anuradha Udunuwara

20. Access Network
20
 Edge of the network
 Enable delivery of services for specific markets
 Enable the connection of telecommunication
services with subscribers
(c) Anuradha Udunuwara

21. Typical Cu access network last (first) mile
OSP
DP CO
(overhead) Edge
CP Network
MDF
Node
Rosette CAB
Primary Ex:- C4/5 switch,
Secondary
Discharger AGW
(Underground) (Underground)
Network demarcation
Ex:- Telephone,
DSU, modem, NTU
(c) Anuradha Udunuwara 21

22. Core Network Evolution
22
 Connection oriented
 X.25 (70s)
 FR(80s)
 ATM (90s)
 MPLS
 Connection-less
 Ethernet
 IP
(c) Anuradha Udunuwara

23. Speeds
 TDM  Ethernet
PDH
0 ~ 100 Gbps

 E1 / 2 Mbps 
 T1 / 1.5 Mbps
 E3 / 34 Mbps
 T3 / DS3 / 45 Mbps
 SDH
 STM-1 /155 Mbps
 STM-4 / 622 Mbps
 STM-16 / 2.5 Gbps
 STM-64 / 10 Gbps
 STM-256 / 40 Gbps
(c) Anuradha Udunuwara 23

24. WIRELESS NETWORKS

25. Types of wireless networks
25
 Wireless Personal Area Networks (WPAN)
 Wireless Local Area Networks (WLAN)
 Wireless Metropolitan Area Networks (WMAN)
 Wireless Wide Area Networks (WWAN)/ Cellular
(mobile) network
(c) Anuradha Udunuwara

26. 26
Source: http://en.kioskea.net/contents/wireless/wlintro.php3
(c) Anuradha Udunuwara

27. WPAN
27
 interconnect devices within a relatively small area,
that is generally within a person's reach
 Ex:- Bluetooth, IR, ZigBee, Wi-Fi, NFC
(c) Anuradha Udunuwara

28. WLAN
28
 links two or more devices over a short distance using
a wireless
 use of spread-spectrum or OFDM technologies may
allow users to move around within a local coverage
area, and still remain connected to the networks
distribution method
 Ex:-Wi-Fi
(c) Anuradha Udunuwara

29. WMAN
29
 connects several WLANs
 Ex:-WiMAX
(c) Anuradha Udunuwara

30. WWAN/Cellular (mobile)
30
 radio network distributed over land areas called cells, each served by at least one
fixed-location transceiver, known as a cell site or base station (BTS)
 each cell characteristically uses a different set of radio frequencies from all their
immediate neighboring cells to avoid any interference
 When joined together these cells provide radio coverage over a wide geographic
area. This enables a large number of portable transceivers (e.g., mobile phones,
pagers, etc.) to communicate with each other and with fixed transceivers and
telephones anywhere in the network, via BTS, even if some of the transceivers are
moving through more than one cell during transmission
 originally intended for cell phones, today carry both data and voice
 Ex:- GSM, GPRS, UMTS, Satellite
(c) Anuradha Udunuwara

31. 31
Source : http://www.oafrica.com/mobile/all-about-african-4g-lte/
(c) Anuradha Udunuwara

32. 32
Source : http://tutorials.telecomseva.com/index.php/2012/01/generation-of-wireless-network/
(c) Anuradha Udunuwara

33. 33
Source : http://www.4gamericas.org/index.cfm?fuseaction=page&sectionid=249
(c) Anuradha Udunuwara

34. 34
Source : http://www.engadget.com/2008/07/25/lte-wimax-vie-for-itus-love-and-affection/
(c) Anuradha Udunuwara

35. Mobile Networks
(Global System for
(General Packet (Universal Mobile
Mobile (Evolved Packet
Radio Service) Telecommunications System)
35 Communications) System)
(Evolved Packet Core)
(BSC) (RNC)
(GSM EDGE (Enhanced Data Rates for GSM Evolution) (Universal Terrestrial Radio Access Network) (Evolved UTRAN)
Radio Access Network)
Source: http://www.3gpp.org/LTE (c) Anuradha Udunuwara

36. INTERNATIONAL
NETWORKS

37. Types of connectivity
37
 Satellite
 Submarine cable
 Coaxial
 Fiber
(c) Anuradha Udunuwara

38. 38 (c) Anuradha Udunuwara

39. Source : http://submarine-cable-map-2013.telegeography.com/
39 (c) Anuradha Udunuwara

40. NGN

41. Vertical to Horizontal
41
Legacy: Future:
Service Specific Networks NGN architecture for services
Service
Service
Service
Service
Service
Service
Control and Signaling Network
rk
Netwo
rk
Netwo
Network
Network
Network
Converged
Network
(c) Anuradha Udunuwara

42. Why NGN?
42
The NGN concept takes into consideration new realities in the
telecommunication industry characterized by factors such as the
need to converge and optimize the operating networks and the
extraordinary expansion of digital traffic
(i.e. increasing demand for new multimedia services, increasing
demand for mobility, etc.)
NGN also aims to tackle important concerns raised from the use of
current IP-based services:
(i.e. QoS and security) (c) Anuradha Udunuwara

43. Definition
43
NGN is a packet-based network able to provide
Telecommunication Services to users and able to make use of
multiple broadband, QoS-enabled transport technologies and in
which service-related functions are independent of the underlying
transport-related technologies. It enables unfettered access for
users to networks and to competing service providers and
services of their choice. It supports generalized mobility which will
allow consistent and ubiquitous provision of services to users.
[ITU-T Recommendation Y.2001 (12/2004) - General overview of NGN]
(c) Anuradha Udunuwara

44. Fundamental aspects
44
 Packet-based transfer
 Separation of control functions among bearer capabilities, call/session, and application/service
 Decoupling of service provision from transport, and provision of open interfaces
 Support for a wide range of services, applications and mechanisms based on service building blocks (including real
time/streaming/non-real time services and multi-media)
 Broadband capabilities with end-to-end QoS and transparency
 Interworking with legacy networks via open interfaces
 Generalised mobility
 Unfettered access by users to different service providers
 A variety of identification schemes which can be resolved to IP addresses for the purposes of routing in IP networks
 Unified service characteristics for the same service as perceived by the user
 Converged services between Fixed and Mobile networks
 Independence of service-related functions from underlying transport technologies
 Support of multiple last mile technologies
 Compliant with all Regulatory requirements, for example concerning emergency communications and security/privacy, etc.
(c) Anuradha Udunuwara

45. Converged Network Model
45
(c) Anuradha Udunuwara

46. 46
DSLAM (AGW) PON 3G
MSAN (AGW) WiMAX
(c) Anuradha Udunuwara

47. NGN Reference Architecture, Cont.,
47
(c) Anuradha Udunuwara

48. NGN Components
48
(c) Anuradha Udunuwara

49. Segments of NGN Architecture
49
VoIP
IMS Controllers
Control and Signaling Video
CDMA Network Application
Customer FTTx Core Non-IMS Controllers
Equipment Access Network Data
Network Aggregation
xDSL Network IM
Wimax
User Access Aggregation Core Control and Application
Equipments Network Network Network Signaling Network
Network
(c) Anuradha Udunuwara

50. Next Generation Access Options
50
Next
TDM NGN Generation
POTS ADSL
V5.2 ADSL2+ Access
FTTx, ETH
VDSL WiMAX, LTE
VDSL2
(c) Anuradha Udunuwara

51. FTTx Technologies
51
(c) Anuradha Udunuwara

52. Services /Application (wire-line)
 Voice  Data
PSTN TDM
Legacy

  Services : Leased line
 Access : Copper 

Access : Copper, fiber
Transmission : PDH, SDH
 Transmission : PDH, SDH  Narrowband
Services : Internet
Switching : Circuit Switching

  Access : Dialup (PSTN)
 Transmission : PDH, SDH
 NGN  IP
 Services : L3 VPN (IP/VPN), L2 VPN (VPLS)
NGN
 Access : Copper, fiber  Access : Copper, fiber
 Transport : IP/MPLS
 Aggregation : Carrier Ethernet  Broadband
 Core : IP/MPLS 

Services : Internet, IPTV, VoBB
Access : Copper, fiber
 Switching : Packet Switching  Transport : IP/MPLS
(c) Anuradha Udunuwara 52

53. TRANSFORMATION

54. 54
• Voice centric -> data centric
• Wired -> wireless
– Copper -> fiber
• Legacy -> NGN
– Verticals -> convergence
– Circuit Switching -> Packet Switching
• TDM -> IP
(c) Anuradha Udunuwara

55. 55
Source : http://www.chtglobal.com/enterprise/integrated-voice-data/
(c) Anuradha Udunuwara

56. Migration to an IP converged network
Legacy NGN
Multiple Applications Multiple Applications
Multiple Control Layers Single Control Layer
Multiple Transport Networks Single Transport Network
Multiple Access Network Multiple Access Network
Multiple Access Connection Single Access Connection
56 (c) Anuradha Udunuwara

57. Access network migration (example)
Current Short Term Long Term
AGW, C5 switch AGW (Cu)
FTTx
Data Network AGW (Cu)
Metro Ethernet Metro Ethernet Metro Ethernet
CDMA CDMA
2G/3G/3.5G 2G/3G/3.5G LTE
WiMAX WiMAX
57 (c) Anuradha Udunuwara

58. Issues with Legacy Networks
58
 Low bandwidth
 No flexibility to scale
 High cost of installation
 Slow provisioning
 Bandwidth growth inflexible/non-linear
 Limited by multiplexing hierarchy
 TDM-based access: inefficient for converged data
(c) Anuradha Udunuwara

59. Understanding the BIG picture
59
Revenue
generation
Infrastructure
enabler
OPEX reduction
and efficiency
gain
(c) Anuradha Udunuwara

60. CSP broadband equation
60
Urban Sub-urban Rural
Wired Wireless
wired/wireless
Ex:- FTTH Ex:- LTE
(c) Anuradha Udunuwara

61. About the Author
61
Eng. Anuradha Udunuwara is a Chartered Engineer by profession based in Sri Lanka. He has nearly a decade
industry experience in strategy, architecture, engineering, design, plan, implementation and maintenance of CSP
Networks using both packet-switched (PS) and Circuit-Switched (CS) technologies, along with legacy to NGN
migration. Eng. Anuradha is a well-known in the field of CSP industry, both locally and internationally.
Graduated from University of Peradeniya, Sri Lanka in 2001 with an honors in Electrical & Electronic Engineering,
Eng. Anuradha is a corporate member of the Institution of Engineers Sri Lanka, a professional member of British
Computer Society, a member of Institution of Electrical & Electronic Engineers, a member of Institution of
Engineering & Technology (formerly Institution of Electrical Engineers), a member of the Computer Society of Sri
Lanka, a life member of Sri Lanka Association for the Advancement of Science, senior member of the Carrier
Ethernet Forum, member of the Internet Society, member of the Internet Strategy Forum, member of the Internet
Strategy Forum Network, member of the Ethernet Academy, member of the NGN/IMS forum and member of the
Peradeniya Engineering Faculty Alumni Association. He is also an ITIL foundation certified and the only MEF-CECP in
the country.
In his spare time Anuradha enjoys spending time with his family, playing badminton, photography, reading and
travelling.
He can be reached at udunuwara@ieee.org
(c) Anuradha Udunuwara