e up bandwidth capacity for data backup. Computing and Enabling Technologies Certeon VA = Virtual appliance VM OS Certeon virtual Branch/remote Certeon appliance office VM os Firewall Backup Certeon virtual appliance Data center Backup site with aCelera Sync Server Centralized configuration virtual appliance management system Figure 1-5 Certeon aCelera Virtual Appliance software loaded onto a virtual computer on a physical server at headquarters and at remote branches. Proprietary hardware is not required. (Courtesy Certeon) WAN acceleration software is often installed on standard computers at the cus- tomer's locations. Certeon's software is downloaded onto virtual servers (servers that can run multiple operating systems and applications), in data centers, and at remote locations. (See the section "Single Servers Functioning As Multiple Servers via Vir- tualization," later in this chapter, for information on virtualization.) Additionally, the software can be downloaded to a desktop computer for remote employees. Figure 1-5 portrays an example of WAN acceleration and optimization software installed at head- quarters and branch offices. USING PROTOCOLS TO ESTABLISH A COMMON SET OF RULES Protocols enable disparate devices to communicate by establishing a common set of rules for sending and receiving. For example, TCP/IP is the suite of standard protocols used on the Internet with which different types of computers, running a variety of operating systems, can access and browse the Internet. TCP/IP is a prime factor in the Internet's widespread availability. Using Protocols to Establish a Common Set of Rules The fact that protocols used on the Internet are available for free in their basic form and work with a variety of browsers, operating systems, and computer platforms makes them attractive interfaces for enterprises, hosting, and cloud-computing sites that support remote access to services such as Microsoft Office documents. A web- based interface compatible with many types of computers and operating systems enab