the use of a complex mathematical algorithm to reorder bits SO that only the receiving end with matching encryption is able to decipher and read them. To access the corporate network, customers with broadband services log on to the public Internet. From there, traffic is routed to the Internet and then to the megabit or gigabit dedicated access line connected to their remote place of business. For organizations that allow remote access to headquarters applications and files, remote users are routed via the Internet to the organization's headquarters, as indicated in Figure 5-3. www.TechnicalPDF.com Secure tunnels files from hackers Internet Computer with Virtual Private Network (VPN) software for secure access to remote files Remote data center Figure 5-3 Secure access to headquarters' files over an IP VPN with tunneling protocol to protect data transmitted over the Internet. The most common security protocols on access networks are the following: Internet Protocol Security (IPsec) This is an older security protocol that requires software to be installed in every computer that accesses the network remotely. Layer 2 Tunneling Protocol (L2TP) This protocol evolved from an earlier protocol Point-to-Point Tunneling Protocol (PPTP) developed by Microsoft; it has stronger authentication security for screening devices that access the network. L2TP is also used with IPsec. Transport Layer Security (TLS) This is a newer access method that does not require client software. The earlier version was Secure Socket Layer. www.TechnicalPDF.com The Complexities of Using VPNs with IPsec Internet Protocal Security (IPsec) is a protocol that requires users to install IPSec software on their devices. IT staff members distribute software to each person's computer. (They also handle calls from employees who are having trouble logging on to the VPN or who have lost their laptop or smartphone.) Employees can only access their e-mail and other applications from their own computer or supported mobile smartphone, such as an Android or iPhon