The present invention relates to an arrangement adapted to be provided in a server node (50) in a communication system, handling a large number of clients, comprising a number of interface boards (201, 202, 203) handling one or more protocols for communication with different nodes and a number of processing means (101, . . . ,106) adapted to serve a plurality of clients which may use a number of different types of identities when addressing the server node (500). It comprises load distribution control means adapted to handle clients using at least two different categories of addressing identities separately, and to distribute the clients to processing means (101, . . . ,106), and being adapted to provide a number of load index values (LI1LI36), exceeding the number of processing means, and load index mapping means mapping between load index values and processing means in a load index mapping table (30, 301, 302, 303, 3011-3016). It is further adapted to distribute mapping tables or to substantially each interface board (201,202,203) and each processing means (101, . . . ,106), and first mapping means comprising mapping algorithm (211,212,213) handling clients or subscribers using a first category of identity comprising a for the server node normal identity e.g. generated externally, said mapping algorithm being adapted to establish a load index value (LI1) for an incoming message using said firs.t category of identity, and second mapping means (221,222,223) comprising a second mapping algorithm for mapping second category or internally generated identities to respective load index values such that a client will be handled by the processing means (101, . . . ,106) mapped to the corresponding, established load index value.