Arrangement of data synchronization in a telecommunications system

A method of detecting duplicates in a synchronization system comprising at least one client device and at least two synchronization servers, the method comprising:

• allocating to the data units to be synchronized first identifiers for use in the client device and second identifiers for use in the synchronization server;
• maintaining mapping tables for the synchronization servers by adding to the mapping table first identifiers and second identifiers allocated to the data units to be synchronized via the synchronization server,
• comparing the identifier pairs formed by the first and second identifiers added to the mapping tables of different synchronization servers;
• and
• preventing the recording of the data unit under synchronization as a response to a data unit according to the first identifier allocated to said data unit being already recorded on the basis of the mapping tables.

A synchronization system comprising at least one client device and at least two synchronization servers,

• the synchronization system comprising at least one mediator which is configured at least to:
• maintain a mapping table for at least one synchronization server, the mapping table comprising for the data units to be synchronized first identifiers for use in the client device and second identifiers for use in the synchronization server;
• compare the identifier pairs formed by the first and second identifiers of different mapping tables;
• detect the duplicates on the basis of the comparison;
• and
• cause at least part of the identifier pairs in the mapping table to correspond to each other.

A synchronization device for a synchronization system comprising client devices and synchronization servers, said synchronization server comprising:

• means configured to maintain at least one mapping table for at least one synchronization server, the mapping table comprising for the data units to be synchronized first identifiers for use in the client device and second identifiers for use in the synchronization server;
• means configured to compare the identifier pairs formed by the first and second identifiers;
• and
• means configured to cause at least part of the identifier pairs of the mapping table to correspond to each other.

A computer program product loadable to the memory of a computer, said computer program product comprising a program code which, when executed in a processor of a computer, causes the computer to

• maintain at least one mapping table for at least one synchronization server, the mapping table comprising for the data units to be synchronized first identifiers for use in the client device and second identifiers for use in the synchronization server;
• compare the identifier pairs formed by the first and second identifiers of different mapping tables;
• detecting the duplicates on the basis of the comparison;
• and
• causing at least part of the identifier pairs in the mapping table to correspond to each other.