《《Nishan_iSCSI_Technical_White_Paper》.pdfVIP

iSCSI Technical White Paper White Paper iSCSI Technical White Paper Nishan Systems 3850 North First Street San Jose, CA 95134 Tel 408-519-3700 Fax 408-519-3705 www.NishanS © 2001 Nishan Systems Page 2 White Paper iSCSI Technical White Paper Introduction In this paper we will examine the main technical attributes of the iSCSI protocol and what is required to transport block data in a native IP end-to-end storage solution. The iSCSI protocol initiative has to contend with the inherent contradiction posed by the requirements of SCSI for stable, responsive communications and the potentially unstable environment typical of IP networks. The iSCSI protocol specification therefore devotes ample space for validation of data and command exchanges as well as for recovery from data loss that may be engendered by the lower layer transport. iSCSI is based on the Small Computer Systems Interface (SCSI) which enables host computer systems to perform block data input/output (I/O) operations with a variety of peripheral devices. Target devices may include disk and tape devices, optical storage devices, as well as printers and scanners. The traditional SCSI connection between a host system and peripheral devices is based on parallel cabling, which has inherent distance and device support limitations. For storage applications, these limitations have fostered the development of new technologies based on networking architectures such as Fibre Channel and Gigabit Ethernet. IP Storage networks based on serial gigabit transport layers overcome the distance, performance, scalability, and availability restrictions of parallel SCSI implementations. By leveraging SCSI protocols over networked infrastructures, storage networking enables flexible high-speed block data transfer