iSCSI uses a worldwide unique name to identify an iSCSI device, either target or initiator. This name is similar to the WorldWide Name (WWN) associated with Fibre Channel devices and is used as a way to universally identify the device.

iSCSI names are formatted in two different ways. The first is by an iSCSI qualified name, commonly referred to as an IQN name. The second, much less common method, is through an enterprise unique identifier, also referred to as an EUI name.

For more details on iSCSI naming requirements and string profiles, see RFC 3721 and RFC 3722 on the IETF Web site.

iSCSI qualified names take the form iqn.yyyy-mm.naming-authority:unique name, where:

yyyy-mm is the year and month when the naming authority was established.

naming-authority is usually reverse syntax of the Internet domain name of the naming authority. For example, the iscsi.vmware.com naming authority could have the iSCSI qualified name form of iqn.1998-01.com.vmware.iscsi. The name indicates that the vmware.com domain name was registered in January of 1998, and iscsi is a subdomain, maintained by vmware.com.

unique name is any name you want to use, for example, the name of your host. The naming authority must make sure that any names assigned following the colon are unique, such as:

iqn.1998-01.com.vmware.iscsi:name1

iqn.1998-01.com.vmware.iscsi:name2

iqn.1998-01.com.vmware.iscsi:name999

Enterprise unique identifiers take the form eui.<16 hex digits>.

For example, eui.0123456789ABCDEF.

The 16-hexadecimal digits are text representations of a 64-bit number of an IEEE EUI (extended unique identifier) format. The top 24 bits are a company ID that IEEE registers with a particular company. The lower 40 bits are assigned by the entity holding that company ID and must be unique.

In many cases, the IQN format is chosen over the EUI format for readability and as a more user-friendly method of assigning names.