Cause of mobile outage identified

Orange France has identified the cause of a major mobile service disruption on October 21, which affected millions of users. The outage was traced to a software issue in Nokia equipment used in the core network, which handles SIM card authentication and routes voice, SMS, and data traffic.

Nokia equipment triggered the failure

The malfunction was triggered when the Nokia equipment received error messages, causing it to restart repeatedly in a loop. This issue impacted the core network infrastructure, which manages the connectivity of 22.65 million professional and consumer SIM cards in France.

Redundancy mechanisms failed

Jérôme Hénique, CEO of Orange France, explained in an interview with Le Figaro that the incident was unusual because the redundancy mechanisms—designed to take over if the primary system fails—did not function as intended. The backup equipment ran the same version of Nokia software as the primary system, leading to the same error being replicated.

Outage lasted over five hours

As a result, Orange's infrastructure had no automated recovery capacity for more than five hours. The outage was detected by late morning on October 21 and required manual intervention from Nokia. The company isolated the faulty code around 5 p.m., allowing a gradual reactivation of network services in the evening.

Some services remained operational

While 3G, fixed connections, and emergency calls remained functional, several million 4G and 5G lines were disconnected during the outage. The incident has raised questions about the modernization of Orange's network, as the company has been migrating to a new 5G SA core supplied by Nokia since 2022.

Outage affected new network users

The affected area corresponded to the lines that had already been transferred to the new application stack as part of the migration. The company is migrating its network in batches of 100,000 subscribers, which is why some users on the old core network continued to function normally during the outage.