## Internet Small Computer System Interface qualified name 

Internet Small Computer System Interface (iSCSI) qualified name (IQN) refers to special names that identify both iSCSI initiators and targets. IQN is one of the three name formats that is provided by iSCSI. The IQN format is iqn.< yyyy - mm> .< reversed domain name > . For example, the default for an SVC node can be in the following format: 

iqn.1986-03.com.ibm:2145.< clustername >.< nodename > 

## Internet storage name service 

The Internet Storage Name Service (iSNS) protocol that is used by a host system to manage iSCSI targets and the automated iSCSI discovery, management, and configuration of iSCSI and FC devices. It was defined in Request for Comments (RFC) 4171. 

## Inter-switch link hop 

An inter-switch link (ISL) is a connection between two switches and counted as one ISL hop. The number of hops is always counted on the shortest route between two N-ports (device connections). In an SVC environment, the number of ISL hops is counted on the shortest route between the pair of nodes that are farthest apart. The SVC supports a maximum of three ISL hops. 

## Input/output group 

A collection of volumes and node relationships that present a common interface to host systems. Each pair of nodes is known as an I/O group. 

## I/O throttling rate 

The maximum rate at which an I/O transaction is accepted for a volume. 

## iSCSI initiator 

An initiator functions as an iSCSI client. An initiator typically serves the same purpose to a computer as a SCSI bus adapter would, except that, instead of physically cabling SCSI devices (like hard drives and tape changers), an iSCSI initiator sends SCSI commands over an IP network. 

## iSCSI session 

The interaction (conversation) between an iSCSI Initiator and an iSCSI Target. 

## iSCSI target 

An iSCSI target is a storage resource located on an iSCSI server. 

## Latency 

The time interval between the initiation of a send operation by a source task and the completion of the matching receive operation by the target task. More generally, latency is the time between a task initiating data transfer and the time that transfer is recognized as complete at the data destination. 

## Least recently used 

Least recently used (LRU) pertains to an algorithm used to identify and make available the cache space that contains the data that was least recently used. 

## Licensed capacity 

The amount of capacity on a storage system that a user is entitled to configure. 

