Method for implementing terminal roaming and managing in the soft switch-based next generation network

It is a method for implementing terminal roam and management in the soft switch-based Next Generation Network, comprises: a user terminal moving on the IP network, when the IP address changing, the user terminal registering at a soft switch controlling device again, the user terminal attaining the allocated IP address of the said soft switch controlling device and registering at the exchange controlling device, after the soft switch controlling device receiving the register request of the user terminal, it attaining the user data of the said terminal from a database. The soft switch controlling device judges whether the user terminal roaming, if it roaming, the soft switch controlling device further judges whether allowing the user terminal to access, if the user terminal roaming and being allowed to access, then the soft switch controlling device transmits the transmission success response to the user terminal, the user terminal accesses to the soft switch controlling device. This method can provide the function of terminal roaming in the NGN, implementing the roaming management for the terminal, including the roaming right management function, roaming identification function and roaming charge function.