The need for a network demand model arises as the importance of access to the Internet to deliver essential services increases. The ability to anticipate bandwidth needs is critical for efficient service provisioning and intelligent decision-making in the face of rapidly growing traffic and changing traffic patterns. The purpose of this paper is to develop a network demand model to explain the current and future flow of Internet traffic around the globe and thereby understand the future bandwidth needs for domestic as well as for the international links. We develop a model based on previously observed traffic patterns and the theory of network externality. Based on this network externality concept, we assume that the flow of traffic among different countries around the world is directly linked with the relative number of hosts available in those countries. The model is then used to predict future traffic flow among seven regions in the world, distinguishing between domestic and international traffic and inbound versus outbound traffic for each region.