NTT DOCOMO reported on the background and future measures that occurred on October 14 and the future measures.Although some of the 3Gs remain in the afternoon of the 15th, most of them have recovered early in the morning on the 15th.The recurrence prevention measures are said to be completed at the latest in late October.
This communication failure occurred from around 17:00 on October 14, and was announced as recovery (partially recovered) at around 19:57, about 3 hours later, and at 5:05 on the following day, 5G and 4G.Is recovering from the obstacle.The 3G has been regulated at 16:00 on March 15, and it is difficult to use it in some parts.
Congratulations occurred in the equipment in the core network, and some terminals could no longer be connected to a docomo net.In addition to IoT terminals such as communication modules (taxi electronic payments and vending machines, etc.), it was difficult to use both voice and data communication on mobile phones and smartphones.As a result of conquests accompanied by congestion, more terminals and users were affected.
It was about 2 million users nationwide, including the IoT device, which was directly affected by failing to "position registration" and could not connect to the network.Even if the location registration was possible, the network was crowded, and some users were difficult to use, so 2 million users are not the overall scale.In DOCOMO, from the occurrence of failure to the early morning of the 15th, voice calls decreased by 15%year -on -weekly, and data communication decreased by 4%, and many users seem to have been affected.
左から、NTTドコモ 常務執行役員 ネットワーク本部長の小林宏氏、代表取締役副社長の田村穂積氏、サービス運営部長の引馬章裕氏The fundamental cause is that bugs have been found in new equipment of IoT -related servers (subscriber/position information server).It was said that a defect was found in the processing of roaming terminals from overseas, and the switching work that had been performed on the 14th was canceled, and the server where the IoT terminal was connected was returned to the old equipment.
The direct cause was that this cut -back was implemented in the operation of the IoT device, which was not used in the operation of the normal IoT terminal.As a result, about 200,000 location registration signals from the IoT device flowed into the old equipment in a short period of time, causing congestion.Facilities such as other signals and voice exchanges of the docomo network have been linked to congestion.
In addition, these old equipment (two places) manages IoT terminals nationwide, and the effects of problems have been spread nationwide.DOCOMO is working on network virtualization, but the old facilities that occurred this time were not virtualized facilities.The new equipment also improves the processing capacity, and can be processed even at a signal of this scale.Switching to new facilities will be performed again.
発生した事象について再発防止策について
In the mobile phone and smartphone of ordinary docomo users, the congestion occurs in the signal exchange, resulting in "location registration", which is one of the basic control signals exchanged in the background.When the registration signal was needed, it was not connected to the docomo net.In addition, users who were able to register for location were affected by the congestion of the network, making it difficult to use.
The location registration signal is essential for using voice calls, and is required for data communication (when traveling between base stations).For this reason, it seems that data communication of terminals that did not move in the position was difficult to be affected by communication disorders.
一般ユーザーへの影響It takes about 3 hours from the occurrence of a communication failure at 17:00 to the announcement of "recovery in a part", and after that, it has been difficult to use with ordinary mobile phones and smartphones.It is a signal, and it took a long time to calm down.In addition, there is no mechanism to control the signal from the IoT device and the signal from the normal mobile phone / smartphone, so it has to be regulated uniformly, and it has been long -time for smartphones to be difficult to use.。
Regarding the fact that it takes a long time to recover 3G, it is necessary to work more and more, and as a result, it is returned to the old facilities in a time -consuming manner.In general, IoT communication modules that use 3G nets are widely used, such as taxi payment terminals and vending machines communication functions, and are likely to be working carefully.
[Update] The disability recovered all at 22:00 on October 15.(0:00 postscript on the 16th)
Occurrence around October 14th occurs on October 14 from 7:57 pm on October 15th, 5g at 5:05 am, 4G recovery on October 15th, 3G recovery at 10:00 pm
If the 3G is displayed in the 4G contract, the following operations are tried to re -connect to 4G.
(1) Change of priority network changes: "Settings" → "Mobile communication" → "Call Options" → "Voice Call and Data" 3G, then set again to 4G (2) In -machine mode.ON/OFF (3) Restart the terminal
