December 28, 2021 Report from NTT Docomo Inc. on Measures Taken to Prevent Recurrence of Telecommunications Accident and Results of Emergency Inspection of Other Mobile Phone Carriers

The Ministry of Internal Affairs and Communications (MIC) has received a report from NTT Docomo Inc. (headed by II Motoyuki, President and CEO) on the measures taken to prevent the recurrence of the telecommunication accident, which occurred on October 14, 2021. In addition, MIC opens the results of the emergency inspections conducted on other mobile phone carriers to the public.

1. NTT Comomo Inc.’s response to administrative guidance on serious accident

On December 27, 2021, the Ministry of Internal Affairs and Communications (MIC) received a report in response to MIC’s written guidance from the company on the measures taken to prevent the recurrence of the same serious accident in mobile phone services.
The report states that the company is currently taking measures to address the problem that caused the serious accident and introduce a function that will allow it to regulate communications between IoT services and mobile phone services separately. The report also states that the company has already completed measures for the other items.

2. Results of emergency inspections of mobile phone carriers

MIC conducted an emergency inspection of three mobile phone carriers (KDDI Corporation, SoftBank Corp, and Rakuten Mobile, Inc.) to prevent accidents based on the causes and recurrence prevention measures related to the serious accident at NTT Docomo Inc.
As a result of the emergency inspection, each company has confirmed that measures equivalent to those taken by NTT Docomo Inc. to prevent the recurrence of the same accident have been taken, or that measures to prevent the recurrence of the same accident based on this accident case are under consideration.

3. Future action

MIC will closely monitor the progress of the reoccurrence prevention measures that NTT Docomo Inc. took. In the meantime, based on the verification by a telecommunications accident verification meeting, MIC will organize lessons learned from the causes and reoccurrence prevention measures obtained from this accident and disseminate the outcome to the entire industry.