1. Eskom Telecommunications
Assignment
Use Wikipedia to lookup the following terms:
SDH systems
PDS systems
Power line communication

2. Core Activities Provide Support to Eskom’s Core Activities
Teleprotection
Telecontrol
Data: Frame Relay / P-to-P / X.25
Voice Services: Direct / Switched
Area Coverage

3. Core Activities
What is P-to-PA? Peer to peer (or "P2P") networks use diverse connectivity between participants in a network and the cumulative bandwidth of network participants rather than conventional centralized resources where a relatively low number of servers provide the core value to a service or application.
Peer-to-peer networks are typically used for connecting nodes via largely ad hoc connections. Such networks are useful for many purposes. Sharing content files such as FTP containing audio, video, data or anything in digital format is very common, and realtime data, such as telephony traffic, is also passed using P2P technology
What Is Frame Relay?
Frame relay consists of an efficient data transmission technique used to send digital information quickly and cheaply in a relay of frames to one or many destinations from one or many end-points.
Network providers commonly implement frame relay for voice and data as an encapsulation technique, used between local area networks (LANs) over a wide area network (WAN).
Each end-user gets a private line (or leased line) to a frame-relay node. The frame-relay network handles the transmission over a frequently-changing path transparent to all end-users.
What is X.25?
X.25 was used for permanent virtual circuits (PVCs) to connect two host computers in a dedicated link.
This was common for applications using dumb terminals to connect to host computers.
Speeds from 2400bit/s up to 2 Mbit/s, although speeds above 64 kbit/s were uncommon.
What is X.21?
X.21 is the electrical specification interface recommended by the CCITT in 1976.
It is defined as a digital signalling interface between customers (DTE) equipment and carrier's equipment (DCE). And thus primarally used for telecom equipment.
All signals are balanced. Meaning there is always a pair (+/-) for each signal, like used in RS422.
Electrally the X.21 signals are the same as RS422, so please refer to RS422 for the exact details.

4. Provides Telecoms services to:
System Operations & Planning
Transmission Group
Distribution Group
Generation Group

5. SDH Backbone SDH (Synchronous Digital Hierarchy) Backbone Network
622 Mbit/s Fibre Optic - 5 links - 95 kms (Gauteng area)
155 Mbit/s Fibre Optic / Radio links
51 Mbit/s Radio - 57 links
Synchronous networking uses exact timing to transport the data and is tightly synchronized across the entire network, using atomic clocks.
This synchronization system allows entire inter-country networks to operate synchronously, greatly reducing the amount of buffering required between elements in the network.
SDH networks are configured to be highly redundant, with fibre optic networks providing backup.
The optimum network topology is a ring.

6. Data Flow Add / Drop Multiplexers 1 x 155 Mbit/s + monitoring has
62 x E1 circuits running at 2M/Sec
1 x 2Mbit/s circuit has
30 x 64 Kbit/s circuits + monitoring
9600 Kbit/s
Add / Drop Multiplexer: allows the insertion (add) or removal (drop) of the required bandwidth from an SDH signal passing through the multiplexer.
9600 Kbit/s
RTU
TEMSE

7. PDH Systems PDH Systems 34 / 16 / 8 / 4 / 2 Mbit/s Radio links - 443
8 / 4 / 2 Mbit/s Fibre Optic links - 142
Used to connect between sites or from a site to a backbone site
Fibre optic typically used shorter distances
Diverse fibre routes on campus environments

8. PDH Systems The Plesiochronous Digital Hierarchy (PDH)
A technology used to transport large quantities of data over digital transport equipment such as fibre optic and microwave radio systems.
The term plesiochronous is derived from Greek plesio, meaning near, and chronos, time, and refers to the fact that PDH networks run in a state where different parts of the network are nearly, but not quite perfectly, synchronised.
PDH is now being replaced by Synchronous Digital Hierarchy (SDH) equipment.
PDH allows transmission of data streams that are nominally running at the same rate, but allowing some variation on the speed around a nominal rate.
By analogy, any two watches are nominally running at the same rate, clocking up 60 seconds every minute. However, there is no link between watches to guarantee they run at exactly the same rate, and it is highly likely that one is running slightly faster than the other

9. 2 Channel Radio Links 248 Links
Mainly connect Area Coverage repeaters back to a higher-capacity link
Operate in the 406 / 416 MHz and 450 / 460 MHz bands

10. Power Line Carriers Primary function is Teleprotection Single Channel
Audio 300 to Hz
Super Audio to Hz
Only used for voice in exceptional circumstances
All power line communications systems operate by impressing a modulated carrier signal on the wiring system.
The propagation problem is a limiting factor for each type of power line communications

11. Line Trap

12. Power Line Carriers
A power line carrier is communication equipment that operates at radio-frequencies, generally below 600 kilohertz, to transmit information over electric power transmission lines.
A high frequency signal is superimposed on the normal voltage on a power circuit.
The power line carrier is usually coupled to the power line by means of a coupling capacitor in conjunction with a line trap.

13. Network Design Philosophy
SDH Extended “Rings”
Centrally Managed
Largely influenced by the power network
Criticality “A” : 3 Diverse routes / 2 technologies
Criticality “B” : 2 Diverse routes
Criticality “C” : Single route; repair time better than 8 hours

14. Eskom Telecommunications
To Nth Province
To Nth Province
Minerva (B)
Apollo (B)
Sunnyridge
Eloff
Kendal PS (B)
Hekpoort
Witbank
Croydon (C)
Northrand (C)
Vulcan (B)
Megawatt Park (A)
Midas (C)
Pluto (B)
Duvha /
Standby NCC
Jupiter (B)
Simmerpan
Simmerpan (A)
Radio Link
Driehoek
Elandsfontein
Fibre Optic
Eiger (B)
Glockner (B)
622 Mbit/s
155 Mbit/s
Rigi (C)
51 Mbit/s
Alpha
Vaalkop
Ermelo
8 Mbit/s
Fontana
Lethabo (B)
Brakfontein
To Cape
Majuba PS
To Natal
To Natal

16. Questions

17. SDH Frame
The first 9 columns contain the overhead and the pointers. For the sake of simplicity, the frame is shown as a rectangular structure of 270 columns and 9 rows, but the protocol does not transmit the bytes in this order in practice
For the sake of simplicity, the frame is shown as a rectangular structure of 270 columns and 9 rows.
The first 3 rows and 9 columns contain Regenerator Section Overhead (RSOH) and the last 5 rows and 9 columns contain Multiplex Section Overhead (MSOH. The 4th row from the top contains pointers

18. STM-1 Frame
The STM-1 (Synchronous Transport Module level - 1) frame is the basic transmission format for SDH.
The STS-1 frame transmitted in exactly 125 microseconds.
Therefore, there are 8000 frames per second on a fiber-optic circuit designated OC-1 (optical carrier one).
The STM-1 frame consists of overhead plus a virtual container capacity.
The first 9 columns of each frame make up the Section Overhead, and the last 261 columns make up the Virtual Container (VC) capacity.
The VC plus the pointers (H1, H2, H3 bytes) is called the AU (Administrative Unit).

19. STM-1 Frame
Carried within the VC capacity, which has its own frame structure of nine rows and 261 columns, is the Path Overhead and the Container .
The first column is for Path Overhead; it’s followed by the payload container, which can itself carry other containers. Virtual Containers can have any phase alignment within the Administrative Unit, and this alignment is indicated by the Pointer in row four,
The Section overhead of an STM-1 signal (SOH) is divided into two parts: the Regenerator Section Overhead (RSOH) and the Multiplex Section Overhead (MSOH).
The overheads contain information from the system itself, which is used for a wide range of management functions, such as monitoring transmission quality, detecting failures, managing alarms, data communication channels, service channels, etc.
The STM frame is continuous and is transmitted in a serial fashion, byte-by-byte, row-by-row.
STM–1 frame contains
• Total content : 9 x 270 bytes = 2430 bytes
• overhead : 9 rows x 9 bytes
• payload : 9 rows x 261 bytes
• Period : 125 μsec
• Bitrate : 155,520 Mbit/s (2430 x 8 bits x 8000 frames/sec )

20. Equipment Types
Alcatel : SDH Radios / ADMs / Element Manager R2L & R1.5 PDH Radio Links
Alcatel (Newbridge): 28 of 3645s / 290 of 3600s / 574 of 3630s / 85 FRE / Dual 5620 E M
DMC: 15 / 23 GHz PDH Radio Links
Plessey: PDR 23 PDH Radio Links
Timeplex: Synchronisation equipment

21. Fibre Optic Technologies on Power Lines
OPGW (Optical Fibre in Ground Wire) > 132 kV
ADSS (All Dielectric Self Supporting) < 132 kV
GWWOP (Ground Wire Wrapped Optical Fibre)
Add Lash

24. Network Expansions 155 Mbit/s SDH Fibre Optic to Windhoek
622 Mbit/s SDH Fibre Optic to Swaziland / Maputo
Under Investigation:
Fibre Optic cable Ellisras / Selibwe Pikwe (Botswana) / Bulawayo (Zimbabwe)

25. Second Network Operator

26. Second Network Operator
Eskom Telecommunications allocated 15%
Rolled out Km fibre optic cable
NOC established
Equipment containers being commissioned
(n+1) 2.5 Gbit/s backbone
POPs established
R1 Billion spent so far
Both SONET (Synchronous Optical Network) and SDH can be used to encapsulate earlier digital transmission standards, such as the PDH standard, or used directly to support either ATM or so-called Packet over SONET/SDH (POS) networking.
As such, it is inaccurate to think of SDH or SONET as communications protocols in and of themselves, but rather as generic and all-purpose transport containers for moving both voice and data.
The basic format of an SDH signal allows it to carry many different services in its Virtual Container (VC) because it is bandwidth-flexible.

27. Long Distance Fibre Optic Backbone
BLOEMFONTEIN
PIETERMARITZBURG
BEAUFORT WEST
DE AAR
NELSPRUIT
PHALABORWA
RICHARD'S BAY
George
Namibia
Bethlehem
Botswana
Klerksdorp
Mozambique
Poseidon
Swaziland
CAPE TOWN
DURBAN
EAST LONDON
PORT ELIZABETH
PRETORIA
JOHANNESBURG
Umtata
Kenhardt
Maputo
Manzini
Ermelo
Gaberone
Ellisras
Welkom
Ladybrand
Lesotho
Copperton
KIMBERLEY
Rustenburg
Mosselbay
Stellenbosch
Potchefstroom
Cape Peninsula
Tongaat
New Castle
Alice
Brits
Zeerust
Leeudoringstad
Rhodes
Aggeneys
Witbank
Vereeniging
Saldanha
Pietersburg
KOMATIPOORT
MASERU
Beit Bridge

28. Business Opportunities

29. Network Management Network Management Control Centre Operates 24x7
Provides full FCAPS capability
SLA Management
Fault Centre
Spares Management

30. Operations and Field Services
Technical Staff - Approx. 270 (NTD / B.Sc)
Main Centres - E. Cape, W. Cape, KZN, Witbank, Bloemfontein and Gauteng.
Satellite Centres - Pietersberg, Rustenberg, Pietermaritsberg, Kimberly, Klerksdorp and Nelspruit

31. Service Level Agreements
Availabilities (real time)
Platinum 99.9% (max - 4 hrs per incident, 8hrs 46 mins per annum, total window).
Gold 99.6%
Silver 99.2%
Bronze 98%

32. Business Diversity
Eskom - Gx, Tx, Dx and System Operations transmission services
Arivia.kom - IT and internet services
ATNS - bandwidth and services
Caledon Casino CT - Siemens EMS601 mntce
Logitel - Agency
Cell Direct - Agency

33. Questions