Rethinking the role of submarine cables

On March 14, 2024, four submarine fiber optic cables were damaged off the coast of Côte d'Ivoire due to a suspected rockslide. The cable failures left 13 African countries with either disrupted internet services or near-complete outages, with the worst of the disturbances centered in West Africa.

The cuts meant that millions of people couldn't work, make mobile payments, or access digital banking and government services.

Digital public services and infrastructures, which have many benefits, are increasingly being adopted across Africa. But when the internet isn't accessible, neither are the services that people have come to rely on. Witnessing the impacts of internet outages can sow even more doubt among people who are skeptical about embracing these technologies.

"The more we adopt digital public services, the more we need to understand why these cuts have an oversized impact," says Theophilus Benson, professor of electrical and computer engineering. "This will continue to be a challenge unless we explicitly try to understand the different interactions between components of the network and how we can protect each of these interactions."

Those are the types of questions Benson works to address through his research on improving internet resilience in the Global South. Answering them, however, requires different approaches than those commonly used to evaluate internet reliability in the Global North.

"A lot of the tools that exist right now work well, but when you try to apply them in the African context, they fall apart, because the way the internet infrastructure is set up in Africa is very different," he explains.

Benson's team tested the ability of some of the most popular network characterization tools to assess critical components of Africa's network infrastructure ecosystem. Those components include internet exchange points (IXP), subsea cables, and autonomous system numbers, the identifiers for networks with a single shared routing policy. At the Internet Research Taskforce's 2025 Applied Network Research Workshop in Madrid, Spain, Benson's team shared the results of the project; they found that these tools operate less optimally than they do for networks in the Global North, with specific weaknesses such as low detection of IXPs.

The challenge, then, is to try to understand the nuanced differences in Africa's internet ecosystem, how they translate into challenges for existing measurement methods, and how those challenges can be addressed.

To that end, Benson is working to better characterize Africa's digital connectivity landscape through a project called the Africa Internet Observatory. In September, he will share the Observatory's work investigating why the 2024 undersea cable cuts had an outsized effect—or a "larger failure zone than we would expect it to have"—at The Research Conference on Communications, Information, and Internet Policy in Washington, DC. One important aspect of the Observatory's findings is that the problems go beyond the cables themselves; there are other dependencies beyond physical infrastructure that impact internet resilience.

Among the additional challenges faced by Africa's network infrastructure are that much of the content and services on the internet are hosted in Europe, and that web traffic between African countries is often routed through Europe as well. These factors can affect reliability and cause latency issues, in turn potentially hindering the ability of Africa’s network infrastructure to host services like video livestreaming and federated learning.

Carnegie Mellon University has been awarded a grant from the Internet Corporation for Assigned Names and Numbers (ICANN) to analyze the issues impeding internet resilience in Africa. With $450,000 of support from this grant, Benson's team plans to deploy broad scale network assessment devices, develop statistical models to assess layers of the network infrastructure, and create frameworks to evaluate interventions.

To do so, they will measure three important layers of the network infrastructure: the network layer itself, low-level infrastructure providing connectivity through servers; the service layer, the bridge between the network and the end user that routes traffic by translating web addresses into addresses understood by the network; and the application layer, the interface seen and interacted with by the end user. For each layer, they'll evaluate performance, security, and resilience.

This analysis will be important not only for the millions of people who depend on reliable internet services in Africa, but also for industry players like local infrastructure providers, who will benefit from being able to know whether connectivity issues are coming from their layer or another layer of the network.

Likewise, this type of research is informative for policymakers. "Having access to these measurements helps to understand what the dependencies are and whether they change over time, providing them with more insight into what changes they need to make from a policy perspective," says Benson.

Benson also recently joined an advisory group for monitoring subsea cables, formed in 2024 by the International Telecommunication Union, a United Nations agency. He will report his research to the group to help inform guidelines for subsea monitoring and resilience, which will hopefully be translated into laws by UN member countries. "A lot of what we’re doing in the grant will inform our engagement with this working group," says Benson.

Through the work outlined in his recent grant, Benson's group will find sources of reduced internet resilience and identify elements that impact internet stability. By highlighting and addressing gaps in resilience, Benson hopes to help policymakers understand potential paths to protect internet access.