Re: iSCSI Naming and Discovery

["Jim Hafner/Almaden/IBM" <hafner@almaden.ibm.com>]

David,

I'm glad we agree on some things.  At the risk of sounding too preachy...

I wrote:
>> In short, can we split this into two independent questions:
>>
>> 1) what datum does an initiator need to establish the IP connection to
the
>> target?
>>
>> 2) where can an initiator get that datum?

You wrote:
>I would propose that the information required for #1 is the IP address
>and port number as well as an inband representation of the LU.

I'm still trying to figure out where inband representation of LU is
required in this context.

A couple of points:
a) by "target" in the above context, I mean the iSCSI version of a "SCSI
Target Device" (a box which holds many LUs and which has at least one IP
physical node). N.B.  "target" is not a logical unit!
b) Both (1) and (2) address the "how to open the TCP pipe" question, not
what happens after the TCP pipe is open.  This pipe is initiator TCP to
"target" TCP.
c) an initiator does not "connect" to a logical unit.  It connects to a
SCSI Target Device.

The layers (as I see them) are:
  - TCP-to-TCP (open the pipe, certainly requires at least
datum=ipaddress:port)
  - iSCSI-to-iSCSI (login, requires some authentication datum for iSCSI
endpoints)
  - SCSI-to-SCSI (application client to LU device server and task manager
--
     addressing datum at this level is LUNs)

NOTE: Everything in the SCSI-to-SCSI layer is already defined (both
discovery, naming, addressing, protocol, etc.). Everything at a TCP-to-TCP
layer is defined (once the datum is acquired).  This WG needs to define the
iSCSI-to-iSCSI stuff and perhaps assist in answering (2) above to
facilitate the operation of the TCP-to-TCP layer (1).

In SAM terms, the iSCSI-to-iSCSI job is to create the I_T nexus (there is
no LU or LUN datum involved here).

Where in either the TCP or iSCSI layer is a LU identifier or LUN required,
desirable, etc?

(Sorry if this comes across too strong! -- maybe it's just a bad day!)

Jim Hafner