Seacom versus SAT-3/SAFE latency
The SEACOM cable is set to become operational tomorrow, promising to provide South Africa with more affordable international bandwidth prices and ultimately drive down the cost of communications in the country.
The 15 000 km SEACOM submarine fibre-optic cable runs down the East Coast of Africa which, according to certain industry players, mean a longer path to Europe and therefore higher latencies. Consumers, typically online gamers, have also raised questions about the expected latencies over the SEACOM cable.
One broadband user asked SEACOM about the expected latency between Mtunzini in South Africa and Marseille in France. The ‘SEACOM Team’ responded that the “maximum latency on Seacom ranges from 74ms to 94ms, depending on the routing”. These are however one-way numbers, which means that round trip numbers would be in the region of 150 ms to 200 ms.
This raises questions about how latency on the SAT-3/SAFE system compares to SEACOM. According to the SAT-3/SAFE website the latency on SAT-3 between the South African Melkbosstrand landing station and the Sesimbra landing station in Portugal is 60 ms. The latency on the SAFE cable between Mtunzini on the South Coast of South Africa and Penang in Malaysia is estimated to be 46 ms.
From these figures it looks like there is indeed a significant difference between the latency on SAT-3/SAFE and SEACOM, but these figures represent only one portion of the full packet round trip from a broadband user’s computer to an international server and back.
Many facets of a network can influence the effective latency a user experiences, including the last mile and backhaul technologies used, whether the service is shaped or not and what the effective distance is between the user and the ultimate destination.
Local broadband users are typically experiencing latency of between 300 ms and 1 000 ms, with the upper end of the scale typically associated with wireless last mile access. South African ADSL users with shaped bandwidth can also expect higher latencies during busy network periods when playing online games or using services other than web surfing, email and FTP.
SEACOM explains that it is difficult to predict the exact latency end users can expect: “The delay on SEACOM between South Africa and France can be different amongst circuits, depending on which specific fiber path is traversed. The exact delay you measure in a ping test is dependent not only on the international circuit delay (e.g. SEACOM), but is also dependent on other aspects of the routing of your connection by your ISP,” the SEACOM Team pointed out.
“Therefore, without knowing more, SEACOM cannot accurately predict how the results of your ping test will improve, if your ISP subscribes to SEACOM.”
Seacom versus Sat-3/Safe latency
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