Date Added: Sep 2011
IP Multimedia Subsystem (IMS) is the key technology of the Next Generation Network (NGN) and the optimal solution of mobile and fixed network convergence which is approved by the public. Home Subscribe Server (HSS) is not only the data center of the system, but also the key of supporting the user mobility and call controlling. Since the growth of user data, the capacity of HSS storage and computing to the IMS system is very critical. Cloud computing is a successful example for solving the problem that originates from the massive growth of data by using distributed storage and computing in the internet industry.