In the last decay, there has been many information and Internet technologies advances. Due to the advances, enterprises are now easier to be scattered throughout the world to closely reach their customers. However, the distributed global enterprises have to pay the high cost for telecommunications among the globally distributed sites. In this paper, we propose a global packet-phone network that could be built efficiently with low cost for global enterprises to provide international telecommunications, fax, video conferences, and other value added services. The proposed system has been experimented and used by many global enterprises. This paper describes the theory of the global packet-phone network, and discusses how the system is built in practice.