Transcript Eskom Transmission Services

Eskom Telecommunications
Assignment
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Use Wikipedia to lookup the following terms:
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SDH systems
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PDS systems
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Power line communication
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
Provides Telecoms services to:
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System Operations & Planning
Transmission Group
Distribution Group
Generation Group
SDH Backbone
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SDH (Synchronous Digital Hierarchy) Backbone Network
622 Mbit/s Fibre Optic - 5 links - 95 kms (Gauteng area)
155 Mbit/s Fibre Optic / Radio - 100 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.
Data Flow
155 Mbit/s
155 Mbit/s
155 Mbit/s
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.
RTU
9600 Kbit/s
TEMSE
PDH Systems
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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
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
2 Channel Radio Links
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248 Links
Mainly connect Area Coverage repeaters back to a higher-capacity link
Operate in the 406 / 416 MHz and 450 / 460 MHz bands
Power Line Carriers
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Primary function is Teleprotection
Single Channel
Audio 300 to 2 700 Hz
Super Audio 2 900 to 3 400 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
Line Trap
Power Line Carriers
• A power line carrier is communication equipment that operates at radiofrequencies, 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.
Network Design Philosophy
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
Eskom Telecommunications
To Nth Province
To Nth Province
Minerva (B)
Apollo (B)
Sunnyridge
Eloff
Kendal PS (B)
Hekpoort
Witbank
Croydon (C)
Vulcan (B)
Northrand (C)
Megawatt Park (A)
Midas (C)
Pluto (B)
Duvha /
Standby NCC
Jupiter (B)
Simmerpan (A)
Radio Link
Driehoek
Eiger (B)
Fibre Optic
622 Mbit/s
Elandsfontein
Glockner (B)
155 Mbit/s
Rigi (C)
Alpha
Vaalkop
Ermelo
51 Mbit/s
8 Mbit/s
Fontana
To Cape
Lethabo (B)
Brakfontein
Majuba PS
To Natal
To Natal
Questions
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
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).
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
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Total content : 9 x 270 bytes = 2430 bytes
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overhead : 9 rows x 9 bytes
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payload : 9 rows x 261 bytes
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Period : 125 μsec
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Bitrate : 155,520 Mbit/s (2430 x 8 bits x 8000 frames/sec )
Equipment Types
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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
Fibre Optic Technologies on Power Lines
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OPGW (Optical Fibre in Ground Wire) > 132 kV
ADSS (All Dielectric Self Supporting) < 132 kV
GWWOP (Ground Wire Wrapped Optical Fibre)
Add Lash
Network Expansions
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155 Mbit/s SDH Fibre Optic to Windhoek
622 Mbit/s SDH Fibre Optic to Swaziland / Maputo
Under Investigation:
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Fibre Optic cable Ellisras / Selibwe Pikwe (Botswana) / Bulawayo
(Zimbabwe)
Second Network Operator
Second Network Operator
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Eskom Telecommunications allocated 15%
Rolled out - 4600 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.
Long Distance Fibre Optic Backbone
Beit Bridge
Ellisras
Pietersburg
Botswana
Mozambique
Gaberone
Brits
Zeerust
Maputo
Rustenburg
Namibia
Ermelo
Potchefstroom
Klerksdorp
Vereeniging
Manzini
Swaziland
Leeudoringstad
New Castle
Welkom
Bethlehem
Aggeneys
Ladybrand
Kenhardt
Lesotho
Copperton
Rhodes
Umtata
Alice
Poseidon
Saldanha
Stellenbosch
Cape Peninsula
George
Mosselbay
Tongaat
Business Opportunities
Network Management
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Network Management Control Centre Operates 24x7
Provides full FCAPS capability
SLA Management
Fault Centre
Spares Management
Operations and Field Services
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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
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%
Business Diversity
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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
Questions