NTT Research and Development 2008 Review of Activities

To ensure the reliability of telecommunication networks, reliability design is usually performed using theoretical models in the network-design phase. However, in this approach, redesign and re-evaluation must be performed every time a new device is introduced, and this involves a very large amount of work. Also, if the actual MTBF^* value of a device happens to differ from the catalog value, then it becomes impossible to ensure reliability at the design stage.

Our proposed technique for the reliability management of telecommunication networks involves analyzing various kinds of outage data that occur in telecommunication networks, and performing statistical processing on the traffic conditions when outages occur, together with the number of customer complaints that result from these outages. In this way, it is possible to quantify and visualize the reliability of telecommunication networks after services start, and to provide support for decision-making with regard to remedial actions in order to improve reliability. This technique has never been used before, and is indispensable for the communication services of NTT whose watchwords are safety and security.

In the future, we will develop reliability management based on this technique in the communication services provided by the NTT Group companies, and we will continue our efforts to ensure that our customers can use these services comfortably.

• * MTBF: Mean Time Between Failure