For nine hours, beginning last Friday afternoon at about 15:00 Paris time until 00:30 Saturday morning, some 26 million subscribers of France Télécom's mobile company Orange were unable to make calls, send text messages, or downlaod data. According to ComputerWorld UK, the database that keeps track of which cell a subscriber is connected to which is called the New Generation Home Location Register suffered a software error. Exactly why the error occurred is not known, and Orange is said to be consulting with equipment suppliers Alcatel-Lucent and Ericsson to try to track down the root cause.
ComputerWorld UK reported that the register, which was supplied by Alcatel-Lucent, is made up of three elements: the front end, the central servers, and the databases. An Orange spokesperson stated in the article that, "There were some inconsistencies in the data, and erroneous messages were exchanged between the different elements. That caused some saturations, leading to a snowball effect that blocked the system."
Subscribers who didn't move from a cell were able to keep their service the longest, but eventually the error-queue in the register became so big that everyone lost service.
French ministers were not amused, and have called for an audit of France Télécom and other critical national infrastructure to ensure that it doesn't happen again, reports this Reuters story. The Reuter story implies that the new French government believes that the outage may be caused by excessive cost cutting by France Telecom.
According to this Bloomberg News article, Orange has 38 percent of the French mobile market (it is the largest Internet provider in Europe), which is experiencing intense competition and job cuts at French Telecom's competitors to reduce their operational costs (France Télécom laid off over 20 thousand staff a few years ago itself). Bloomberg quotes the CEO of France Télécom Stéphane Richard as saying that the outage was an "isolated incident" that had nothing to do with "the level of investment in our networks."
The Wall Street Journal noted that when the network crashed, senior executives frantically tried to call Richard at his country home, but they couldn't reach him; they didn't have his landline number, only his mobile.
France Telecom has said that it will compensate subscribers for the outage, which is expected to cost upwards to $25 million.