ta Centers and IP Private Branch Exchanges Virtual Switches Installed on Physical Servers Virtual switches can be installed as software within host physical servers rather than as stand-alone hardware. This offers the advantage of more tightly integrating appli- cations running on virtual machines with the rest of the data center. With virtual switches, management software identifies each application in the physical server as a separate entity. Thus, it is less complex to troubleshoot problems. The physical server is equipped with Ethernet interfaces for communicating with other Ethernet-connected devices as well as ports adapted to communicate with Fibre Channel interfaces (ports) in SANs. Frames serve the same function as packets. They surround user data with addressing, error checking, and other protocol-related bits. The term "frame" is used in lower-level protocols, such as Ethernet, which is used for communicating within LANs connected to the same switch in the wiring closet. Packets refer to data configured for transmission between LANs and on the Internet by using TCP/IP. Fibre Channel over Ethernet The Fibre Channel over Ethernet (FCoE) protocol is an open standard that was approved by ANSI in 2009. It was developed SO that Fibre Channel SANs could com- municate with 10Gbps Ethernet networks without translating between Ethernet and Fibre Channel protocols. The goal is to simplify structures and communications in data centers. In FCoE, the Ethernet protocol is enhanced with techniques to avoid packet loss in the event of congestion. FCoE currently supports 10Gbps speeds, and higher speeds are planned for the future. Interfaces with FCoE are referred to as Converged Network Adapters (CNAs), which you can see illustrated in Figure 2-2. FCoE encapsulates the Fibre Channel frame into the Ethernet frame. Ethernet bits surround the beginning and end of the Fibre Channel frame, which is encapsulated within the Ethernet protocol. Ethernet headers are added before the Fibre Channel header; Ethernet end-of-frame an