NETWORK ARRANGEMENT

A network arrangement and a method for connecting a message-based system (using message-based synchronization) with an external system by converting the synchronization status received from the external system into the internal synchronization status of the message-based system in an interface node of the message-based system in such a manner that the level in the internal synchronization hierarchy of the message-based system (as indicated by the internal synchronization status) rises or falls corresponding to a corresponding rise or fall of a predetermined magnitude occurring in the synchronization status of the external system. Alternatively, the external system is connected to the message-based system by converting the synchronization status received from the external system into the internal synchronization status of the message-based system in an interface node of the system using message-based synchronization in such a manner that the internal synchronization status achieves a certain constant level in the internal synchronization hierarchy of the system and that the constant level is used together with the synchronization status data received from the external system in selecting the source of synchronization in the message-based system.