596 Dell PowerConnect 55xx Systems User GuideFILE LOCATION: C:\Users\gina\Desktop\Checkout_new\Maintenance Projects\DellContax\sources\CxUGSwitching_iscsi.fmD E L L C O N F I D E N T I A L – P R E L I M I N A R Y 1 0 / 3 0 / 1 3 - F O R P R O O F O N LYOptimizing iSCSI OverviewThe Internet Small Computer System Interface (iSCSI) is an IP-basedstorage networking standard for linking data storage facilities. By carryingSCSI commands over IP networks, iSCSI is used to facilitate data transfersover intranets, and to manage storage over long distances.iSCSI can be used to transmit data over local area networks (LANs), wide areanetworks (WANs), or the Internet, and can enable location-independent datastorage and retrieval.Unlike traditional Fiber channels, which requires special-purpose cabling,iSCSI can be run over long distances, using existing network infrastructure.The protocol enables clients (called initiators) to send SCSI commands(CDBs) to SCSI storage devices (targets) on remote servers. This enablesorganizations to consolidate storage into data center storage arrays, whileproviding hosts (such as database and web servers) with the illusion oflocally-attached disks.The targets listen on a well-known TCP port (or any other TCP port that hasbeen explicitly specified) for incoming connections. The login process isstarted when the initiator establishes a TCP connection to the desired target,through the TCP port that was explicitly specified.The group of iSCSI TCP connections that link an initiator with a target iscalled an iSCSI session.When you connect an EqualLogic device to the switch, and iSCSIoptimization is enabled, the switch automatically recognizes the port towhich the EqualLogic equipment is connected to, and configures the STPMode to RSTP to support fast network convergence.Optimizing iSCSIiSCSI optimization provides the following features:• Ability to assign a specific QoS profile to the iSCSI flows• Display of iSCSI session details (connections, initiator, target, and so on)• Identification of (self-discovered) iSCSI sessions• Identification of iSCSI session termination• Identification of non-active iSCSI sessions
