Read about computers from Apple Computer Corporation. Read more about Ethernet LAN hardware.
Some WANs use satellites that orbit above the earth to pass information from one country to another.
If your site has a Web server, ask your site manager to install a new page that contains an unusual sequence of characters. Then test periodically to see how long a search service takes to learn about the new page. After the previous exercise, ask your site manager to delete the page that was inserted. If so, try selecting the page. Answer these questions in your own words.