Abstract: A method for recovering group data between mobile systems, which incorporate at least one first mobile system, at least one second mobile system, and mobile stations, the method comprising the steps of maintaining group data in a first database of the first mobile system, maintaining group data in a database of the second mobile system. In the method, a recovery request is made for recovering the group data, the second mobile system generates one or more virtual attachment requests for the first database of said group, the second mobile system transmits the virtual attachment request to the first database of the first mobile system, in response to the first virtual attachment request, the group data are updated in the first database.

Abstract: The present invention relates to preventing inconsistency between the data maintained in a master exchange and a backup exchange in a telecommunication system. To ensure a reliable data distribution, the system maintains a copy of the master exchange data in a slave exchange. When the slave exchange receives data from the master exchange or the backup exchange, the received data or the corresponding data previously stored in the slave exchange is selected for use on the basis of comparison of the information included in their update information. That is, the data stored in the slave exchange is sent to the exchange having sent the received data if the data stored in the slave exchange is selected for use; the received data is sent to the master exchange if the data received from the backup exchange is selected for use; and the received data is stored in the slave exchange if the received data is selected for use.