Network operator ponders building a new submarine cable – on land

It’s less bonkers than it sounds given the challenges of wiring Africa

African carrier Seacom is investigating the feasibility of building a submarine cable that would run across the heart of Africa, on land.

Senior Transmission Architect Nic Breytenbach explained that apparent contradiction to The Register by pointing out that submarine cables run up and down Africa’s east and west coasts, but that no single connection crosses the continent. When submarine cables on the east coast – which mostly carry traffic to Europe or Asia – experience trouble, carriers must route traffic south around the Cape of Good Hope, then all the way up Africa’s west coast. Capacity on submarine cables is hard to find, and expensive when available.

The journey around Africa, or routing onto alternative east coast cables, therefore adds unwelcome cost and latency that carriers could avoid by using a connection that cuts across the continent.

But no such connection exists. Breytenbach said the combination of rugged terrain that make construction extremely difficult, the need for energy sources along the route, and political instability have all made it infeasible to build a cable on Seacom’s preferred route from the Kenyan port of Mombasa to the Democratic Republic of Congo’s sliver of South Atlantic coastline.

Seacom thinks a submarine cable could make the route viable, because the tech used for such links doesn’t need energy sources along the way and could run underwater or through swamps whenever possible, making it harder for miscreants to dig it up.

One reason telecom cables attract attacks is the value of the copper they contain. But submarine cables can use aluminum to carry current and won’t have copper inside because they use optic fibers as a medium. Breytenbach thinks that will reduce the likelihood of opportunistic attacks because metal thieves know they can’t score a payday by stealing aluminum.

One challenge to overcome, Breytenbach said, is that designers of submarine cables assume they’ll operate in the cold depths of the ocean. A cable running on Seacom’s preferred route would start just north of the Equator and end at just five degrees south, a very different environment to that envisioned by hardware designers.

But Breytenbach points to the existence of a submarine cable in Lake Tanganyika as evidence submarine systems can be adapted to different environments. The fact that Nokia sells hardened repeaters for submarine cables also makes him optimistic that the hardware needed to build a cross-Africa submarine cable on land is possible.

However, he acknowledges that Seacom will need to address many other issues to make this idea a reality, among them diplomatic negotiations to secure the route, arranging timely maintenance, and figuring out how to transport the cable because the ships used to build submarine cables pack in hundreds of kilometers of cabling. Seacom’s uncertain how to replicate that carrying capacity on land, especially as parts of the route are only accessible by helicopter.

“To be honest we are just exploring it at this stage,” he said, and the company is putting more energy into delivering a new cable called Seacom 2.0 that will connect Africa, Europe, India, and Singapore.

Like many other cables, Seacom 2.0 will run through the Red Sea, an area where recent cable cuts have caused disruptions.

Breytenbach told The Register that problems in the Red Sea are one reason Seacom wants a submarine cable to run across Africa.

“There are some significant challenges,” he said. “But we really think it is doable.” ®