Cross-IP internet roaming method for mobile terminal

A cross-IP internet roaming method for mobile terminal includes such steps as broadcasting the domestic proxy address and one's own ID by mobile terminal, authenticating the ID of mobile terminal by the domestic proxy, intercepting the datagram sent to the mobile terminal, creating tunnel to foreign proxy, forwarding the datagran, authenticating the ID of mobile terminal by foreign proxy, and completing the forward of datagram. Its advantages include high communication continuity, safety and correctness.