3. Search the Internet for four companies that make products for one or more of the five layers of the TCP/IP—OSI architecture. Search for terms introduced in Chapter 6 and in this extension, such as 802.3, 802.11, optical fiber cable, VPN, firewall, switch, FTP, and others. For each company, name one of their products, explain its function, and describe how that product relates to the TCP/IP—

OSI architecture.