.Part 4 SAN Extension and Bridging HP SAN Design Reference Guide 785354-001

• “Software and hardware iSCSI initiators” (page 321)

• “Bridging and routing” (page 332)

• “iSCSI boot” (page 321)

Initiator and target devices

An iSCSI router manages access between iSCSI targets and iSCSI initiators as follows:

• iSCSI target (logical target)—An end-node device that is typically a storage system, storage

router, or bridge. A storage system with iSCSI support is called native iSCSI storage.

• iSCSI initiator (IP host)—A system that starts the exchange of information with an iSCSI target.

IP hosts access the iSCSI target storage systems as if they were directly attached.

iSCSI naming

iSCSI nodes are uniquely named devices (initiators or targets). The nodes have an IP address, TCP

port, and iSCSI name. The iSCSI name can be up to 255 characters in length. Figure 133 (page

319) shows an iSCSI node definition in the context of an IP network.

Figure 133 iSCSI node definition

25161a

IP Network = Network Entity

iSCSI Node (IP device with IP address)

iSCSI Name (up to 255 characters, using either EQN or EUI naming scheme)

Network Portal (IP address and TCP port number)

iSCSI Device (host or storage device)

iSCSI Node

The iSCSI name is independent of the network portal and provides a unique and consistent identity

for an iSCSI node. Although moving a device to another network segment changes its network

portal, the iSCSI name is unchanged and allows the device to be rediscovered.

An iSCSI name is independent of supporting hardware. You can assign an iSCSI name to a device

driver on a host, even if the device driver accesses the network through multiple NICs. A storage

device with multiple connections to the network is also identified by its iSCSI name.

iSCSI naming provides permanent and unique identities for iSCSI nodes. The two naming schemes

are as follows:

• IQN

• EUI

An iSCSI node address consists of the IP address, TCP port number, and IQN or EUI. iSCSI nodes

acquire IP addresses with standard IP services.

Discovery mechanisms

This section describes the mechanisms you can use for discovery requests.

iSCSI concepts 319