An energy company with headquarters in Dallas, Texas, is thinking about developing a system to track the efficiency of its oil refineries in North America.

Each week, the ten refineries—as far as Valdez, Alaska, and as close as San Antonio, Texas—will upload performance data via satellite to the corporate mainframe in Dallas. Production managers at each site will use a personal computer to connect to an Internet service provider and access reports via the Web. Create a high-level network model that depicts the locations that have components supporting this system.