Abstract: A server unit for a multi-user application distributed in a communications network. The server unit comprises at least one storing element for storing application names used only in an application session for an application item during the application session and for storing tag values adapted for application data units for sending application data in the communications network, and mapping elements for mapping at least one of the application names to at least one of the tag values. The present invention also relates to a system in the communication network including the server unit, a method for the server unit and a computer program for the server unit.