The present invention relates to a switching center server comprising: —a blade cluster with a plurality of blades (110), —a plurality of pooled resources accessible by said plurality of blades (110) for handling a call, and —a master (112) provided on one of the blades centrally coordinating the usage of the pooled resources, the master as a central instance being responsible for allocation, de-allocation and maintenance of the pooled resources. At outage of one or more blades, the invention provides mechanisms to keep impacts on ongoing calls to a minimum and to keep pooled resources available to the remaining blades.