Figure 6. Representation of an iSCSI Multi-Connection Session

 

 

 

Connections

 

 

iSCSI Initiator

 

iSCSI

 

 

 

 

 

 

 

 

 

 

Target

 

 

 

 

 

 

 

 

 

 

 

 

 

Session

Session

Network Portals

The individual connections of a session may go through a variety of network infrastructure components (network switches, routers, hubs, etc.). iSCSI is agnostic to the network infrastructure components. The connection endpoints are the IP address/TCP port number pairs that identify the network portals.

7.Portal Groups

A LUN view is a subset of the total set of SCSI LUNs accessible behind an iSCSI target node. To provide a SCSI I-T Nexus with a constant LUN view, each connection of an iSCSI session must have access to exactly the same LUN view. If, for some reason, any connection in a multi- connection session were to terminate, the remaining connections of that session would still have access to all of the LUNs in the LUN view.

Network portals accessing an iSCSI node and having the same SCSI LUN view can be grouped together to define an iSCSI portal group. The portal group is identified by a portal group tag uniquely defined for the iSCSI node.

To access a SCSI LUN View behind an iSCSI target node, an iSCSI address must include the following information:

•the iSCSI node name

•the network portal IP address

•the network portal TCP port number

•the iSCSI target portal group tag

For access to a LUN view through a portal group, there is a single iSCSI node name and a single iSCSI target portal group tag. Multiple network portals (IP address and TCP port pairs) may be defined for a portal group to provide multiple points of access for a network entity through an iSCSI target node to a particular LUN view.

The portal group tag is not necessary in iSCSI initiator node addresses.

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