The present invention relates to an arrangement for simplifying the design and implementation of mobile services in a communication system, especially a telecommunications system, said system comprising distributed hardware and software components which interact in order to provide services to one or more users, and for the purpose of this improved availability it is according to the present invention suggested a solution of introducing in said system a mobility transparency, for thereby enabling facilitated application design including inter alia terminal or personal mobility. Special emphasis is made on solutions based on realising mobility transparency by in-line solution, broker solution and proxy solution.