IBM TotalStorage DS300 Best Practices Manual page 35

Connection termination is also required as a prelude to recovery. Connection
termination can avoid old PDUs from previous connections. (Logout is sent by
the initiator.) Targets request the initiator to issue a Logout through an
Asynchronous Event PDU.
iSCSI naming
Every initiator and target node must have a single name defined for it. This name
is used as part of all sessions established between initiator and target nodes. An
iSCSI initiator or target can have one of two types of names:
iqn (iSCSI qualified name) - its format is iqn plus a date field plus the reverse
DNS name with unique qualifiers. For example:
iqn.2005-08.com.ibm.ral.itso.testred
eui (enterprise unique identifier) - its format is
example: eui.acdc15882005bdef
Both types are meant to be long lived as well as unique in the world and
independent of physical location. Both have a central naming authority that can
ensure their uniqueness.
The DS300 uses iqn names.
The iSCSI name is used as a part of an iSCSI address.
iSCSI addressing
The iSCSI address has the format of:
<IP address>[:<port>]/<iSCSI name>
The IP address can be either IPv4, IPv6, or the fully qualified domain name. The
<port> is optional; it specifies the TCP port that the target is listening for
connections on. If it is not used, the well-known iSCSI port (3260) is assumed.
The <iSCSI name> is the iqn or eui name of the device. It is optional.
The iSCSI address specifies a single path to an iSCSI target. The iSCSI address
is primarily used during discovery. It ensures that the SCSI PDU gets delivered to
the correct agent and does NOT affect any SCSI protocol specific addresses.
iSCSI message synchronization
iSCSI PDUs are of varying length, but TCP does not have a mechanism to
identify these message boundaries within the TCP layer. iSCSI places message
length information in the iSCSI header to delineate the end of the current
message and the start of the next message. A potential problem still exists if
iSCSI PDUs are delivered out of sequence or are missing.
eui
plus 16 hex digits. For
Chapter 2. iSCSI overview
17