this shortcoming cannot be overemphasized. Until the formulation and establishment of iSCSI, it was impossible for a TCP/IP computer to send data directly to a standalone disk array or tape drive that was also directly connected to a TCP/IP network. iSCSI is a protocol that enables SCSI commands to be embedded inside TCP/IP session packets, which must be embedded into Ethernet frames for subsequent transmissions. To explain how it works, we will look at an example of configuration such as the one shown in Figure 11.2. The left side of the figure depicts a corporate traditional data-processing IP-based LAN on which some server (poten- tially among many) is connected. The same server is also connected on an IP-based SAN on which IP storage devices are directly connected. The IP SAN is composed of more than just servers and stor- age devices. Both these classes of systems (connected on the IP SAN) must have an embedded and specialized technology called an iSCSI adapter. iSCSI adapters can assume the role of an iSCSI ini- tiator or iSCSI target. They can also be implemented in the physical form of either a full-fledged board or a sophisticated ASIC. Now let us assume that one of the client devices (a workstation) (X) needs some specific file infor- mation from the server (where it believes the information is stored). It initiates a request over the LAN to the server for that piece of information. The server realizes through some indexing file directory that the information must be retrieved from a specific storage device on the SAN. It then issues spe- cific SCSI commands for that device and passes the task to the iSCSI initiator. The iSCSI initiator will encapsulate these SCSI commands inside a TCP/IP packet(s) that will be embedded into Ethernet frames and sent to the storage device over a switched or routed SAN storage network. The iSCSI tar- get device receives the Ethernet frame, strips it apart and recovers the TCP/IP content, decapsulates the packet, and obtains the SCSI commands needed to retrieve the require