NTT DoCoMo announced plans that would separately manage voice calls and data packet transmissions for some handsets in order to avoid network congestion during major natural disasters. The move is expected to increase the ability to successfully transmit text messages to DoCoMo's i-mode Disaster Message Board service, even if network traffic should rise sharply during a major disaster. DoCoMo users making calls during major disasters would also hear an announcement encouraging them to use the i-mode Disaster Message Board service or NTT's disaster message service instead of calling individuals directly, which will also help to reduce network traffic.
Presently, if network traffic were to become exceedingly heavy during a disaster, DoCoMo could be forced to block traffic in selected areas on a temporary basis to prevent serious degradation of network performance. In some instances, urgent messages sent to the Disaster Message Board could be blocked inadvertently. http://www.nttdocomo.com
- In January 2004, NTT DoCoMo launched an i-mode Disaster Message Board service that allows subscribers in Japan to post personal messages for friends and relatives who might not otherwise be able to contact them in the immediate aftermath of a national disaster, such as a high-magnitude earthquake. NTT DoCoMo said that should a major disaster occur, its network will undoubtedly be extremely busy as — in addition to the heavy traffic among administrative and relief agencies, ordinary users in the affected locale typically attempt outside contact to worried relatives and friends. In the event of severe network congestion, the new packet-based i-mode Disaster Message Board will be given sufficient priority to ensure that it continues to function. Each i-mode user in the disaster area would be able to click an on-screen menu enabling him or her to post up to 10 messages of 100 Japanese characters each. Someone wishing to check for a message left by a person in the disaster area would connect to the Disaster Message Board site, and input that person's cell phone number to display any registered messages.
- There are currently more than 45 million DoCoMo cellular phone users in Japan.
