Information and Communication Technology Technical

More international connectivity on the way for SA

by Hans van de Groenendaal, EngineerIT

The East African Submarine Cable System (EASSy) – one of the nine undersea telecommunications cables that will connect various parts of sub- Saharan Africa to the rest of the world by 2011 – will go into operation in August this year. Cable-laying started at both ends at , on the northern KwaZulu-Natal coastline and in .

Telkom is the South African landing partner routes, EASSy creates redundant fibre access not economically justified to increase the for EASSy. With nine EASSy landing stations in prospects into .” number of fibres," said Johan Meyer, Sudan, Djibouti, Somalia, Kenya, Tanzania, executive: global capacity. EASSy is a 10 000 km undersea cable system Comoros, Madagascar, Mozambique and laid along the East African coastline. Its The submarine cable is routed from South , Telkom is the South African 1,4 Tbps system design capacity, coupled with Africa to Sudan, linking the coastal countries landing partner. its two fibre-pair configuration, equips EASSy of East Africa. An extensive backhaul system As one of the investors in the project, Telkom with the highest capacity of all undersea linking landlocked countries to the coastal is also the network administrator and overall cable systems along the east coast of Africa. countries has been developed and is at restoration liaison officer. The company will Interconnection with various other undersea various stages of completion. manage the cable from its network operations international cable systems will enable On the question of vulnerability to the centre (NOC) at Melkbosstrand with back-up traffic on EASSy to seamlessly connect to elements, consideration is given to the route operations at the NOC at in Mtunzini. Europe, North and South America, the Middle the cable takes to minimise the risk from East and Asia, thereby enhancing the east “EASSy is one of the elements of Telkom’s cable activities such as fishing and anchoring, coast of Africa’s connectivity into the global investment strategy and is a key step towards ocean drilling, fish bites and earthquakes. The telecommunications network. the process of establishing a Telkom fibre various precautions taken include conducting ring capability around Africa,” said Alphonzo The question is often asked why companies ocean bed surveys to select the safest Samuels, Telkom’s managing executive for laying submarine cables do not include more undersea routes; burying cable in sand where wholesale services. “EASSy further increases fibre pairs. The EASSy cable has six pairs of possible damage can be caused especially the robustness of the company’s international fibre strands. “With new technology available at the shallow end; avoiding heavy shipping bandwidth offerings. Together with other which supports the increase in capacity by lanes when approaching landing points; undersea cables and land-based fibre lighting up more colours (wavelengths), it is selecting beaches, bearing in mind that

Fig 2: The cable is stored in two holds of the ship, feeding to a special air- conditioned area on the deck where the repeaters are inserted before being Fig. 1: Cable ship ”Isle de Batz” moored in Durban harbour for fuelling and fed to the area from where the cable is lowered into the trench, dug with a preparation to start laying the cable. special sea plough on the sea bed.

52 March 2010 - EngineerIT Fig. 3: The sea plough is prepared on deck and readied for its journey north. Fig. 4: Technicians on the beach at Mtunzini preparing the earth cable which will The plough is lowered to the sea bed where it opens up a trench into which the be connected to a large steel plate (right). It will be buried to provide the return cable is lowered. There are rocky areas where it is not possible to trench the for the DC current which is supplied to the repeaters via the outer core of the cable. In this case it lies on the rocky surface. cable. The sea bed provides the other leg.

later beach erosion could expose cables; Redundancy vs protection vs restoration designing the shortest land cable route When taking about the vulnerability of submarine cable systems, the term for maximum security; and manufacturing redundancy is freely thrown around and often misunderstood as meaning total cables to exceed the 25-year design life of protection against data or connectivity loss. To put this into perspective EngineerIT the cable system. asked Telkom’s Johan Meyer to explain the difference between redundancy and Telkom has taken special precautions at protection. Mtunzini, where the cable lands, to monitor Redundancy shipping. If shipping gets into the no-go Redundancy means that we have duplicated equipment at the cable stations, area, it is picked up by radar alarm. Using duplicated power converters and generators, etc. Therefore if a single piece of a direct radio link, the harbourmaster at equipment should fail, we have another piece of equipment standing by to take its Richards Bay is alerted and then sends a place. This is the case with all submarine cable systems, offering redundancy between warning to the ship. “We also identify the ship the various landing points and spare fibres should one become faulty. should there be need for future litigation in Protection the case of damage”, said Meyer. Protection entails that we have at least a fully duplicated amount of capacity (fibre) Although EASSy will not be commercially and cards available to reroute traffic on the same cable in the event of an internal active by the time this year’s 2010 FIFA World failure impacting only one path or fibre. Protection would entail that for everything Cup kicks off in June, Telkom’s undersea that is duplicated, automated switching takes place – i.e. a fibre pair failure – then capacity has been significantly upgraded. the traffic is automatically rerouted on the second fibre pair, i.e. a card fails, traffic For example, by end-October last year, SAT-3 is automatically rerouted onto another card, etc. For SAT3 we often refer to this and SAFE were upgraded to at least three arrangement as “in-system” protection so as to avoid confusion with cables that are times their former capacity. SAT3 provides protected using geographically-diverse rings / routes. Both redundancy and protection the shortest route to Europe while SAFE is is used to be able to switch traffic within a few milliseconds around faults on the cable system without having to deploy external means of assistance. the shortest link to Asia. “From an undersea capacity perspective it’s all systems go for Restoration the World Cup," said Samuels.

When a complete failure of the cable system occurs through an external influence e.g “The company’s investments in submarine a ship's anchor that breaks the cable, or the system is powered down for purposes of cables include COLUMBUS3, SEA-ME- repair, to the extent that “in system protection” on the same system is not possible, we WE3 (South East Asia-Middle East- then deploy "restoration". This requires the traffic to be routed onto other cable systems via completely different traffic paths and even different routes with increased latency. Western Europe), SAT3/WASC/SAFE (South Atlantic Telecommunications / West Restoration in most instances is not automatically switched as more than one cable Africa Submarine Cable /South Africa Far system uses the same facilities. So although dedicated hard wiring is in place, East), EASSy, EIG () some additional software and manual patches are required when restoration is and WACS (). implemented. As per the Universal Restoration Manual, it is international practice to attempt achieving restoration on this basis within one hour. For a small number of According to Samuels the investments are services, restoration can be rapidly achieved, however if 10s or 100s of bearers must geared with participation of other operators be patched and restored such a process will take many hours.” which translates to better unit costs and improved customer prices.

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