A major service disruption at telecom company KDDI Corp. earlier this month affected at least 30.91 million people, becoming one of the worst such incidents in Japan, according to an accident report submitted to the communications ministry Thursday.
The disruption, which spanned several days, exceeded the magnitude of a 2018 service outage at SoftBank Corp. in which a record 30.60 million mobile connections had been affected.
The Ministry of Internal Affairs and Communications may issue an administrative order to KDDI as early as next month to prevent a recurrence.
It is also planning to launch discussions regarding the implementation of roaming services -- which allows users to jump onto another carrier's mobile connection in an emergency -- with a panel of experts possibly in the autumn.
The plan comes as phone users were unable to dial emergency numbers such as 110 or 119 for an extended period of time during the outage, which began July 2.
KDDI President Makoto Takahashi is slated to hold a press conference on Friday afternoon in Tokyo regarding compensation to affected users, as well as measures to prevent a similar incident from occurring again.
The provider of the "au" mobile service -- and Japan's second-largest mobile carrier by subscribers -- said the numbers of mobile connections and people affected by the disruption are the same.
KDDI said the failure occurred during maintenance of the router for voice calls, with a configuration error triggering a concentration of traffic that led KDDI to reduce user access.
Around 23.16 million phone users and more than 7.75 million users of mobile data were affected.
The outage that lasted through July 4 also disrupted banking systems, the transmission of weather data, parcel deliveries and network-connected cars, alongside the carrier's low-cost "UQ Mobile," lower-priced "povo," and budget smartphone services.
KDDI at the time said it had affected up to 39.15 million mobile connections, or around 60 percent of its contracts, but amended the number after comparing normal usage volume with that during the outage.
According to the accident report, the disruption began at 1:35 a.m. on July 2 until 3 p.m. on July 4 for a total 61 hours and 25 minutes.
Approximately 86 hours had passed by the time KDDI confirmed that the network was fully restored at 3:36 p.m. on July 5.
Related coverage:
KDDI to pay damages to millions of users after network outage
KDDI mobile service fully restored, ending 86 hours of service disruptions
