The present invention relates to a switching center server (100) handling calls, comprising a blade cluster with a plurality of different blades (110), a distributor (125, 170) distributing a message relating to a call to one of the blades, a master (130, 150) centrally controlling a usage of pooled resources by said plurality of blades (110) for handling the call, wherein the distributor contacts the master for retrieving the information to which blade said message is to be distributed. The different blades in the blade cluster are seen from the outside as one node, so that for message distribution the master is contacted in order to distribute the message relating to a call to the blade that is handling said call.