Dr. Garcia is a business professor at a large state college. At the start of each workday, he opens a Web browser on his office computer and accesses the university’s Web site. From there, he logs into his institution’s "MyCollege" portal with his username and password. From the portal he can access his email, Web pages for each of his courses, and confidential information about the students he advises. Most likely, Dr. Garcia is using what kind of network when using the portal?