Re: iSCSI: Canonical Targets

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

Mark and Steph,

I guess I'm having trouble understanding the issues here.   We seem to be
moving toward three types of iSCSI targets:
1) one for discovery only, suitable for login only by authenticated
initiators, i.e., a one-sided authentication, but ONLY for the purposes of
SendTargets.
2) one "nameless" target ("iSCSI"), again suitable for login only by
authenticated initiators, i.e., a one-sided authentication, but used for
real SCSI stuff
3) all other "named" targets, that may or may not require two-sided
authentication, but are used for real SCSI stuff.

Frankly, I think I see no real need for the second one (a SCSI-functional
thing with no true name).   The third one can perform the function of the
second one if the initiator doesn't bother to authenticate the target's
name (provided it has a straightforward way to get the name).  The first
one was what we were moving to as the functional use of the "iSCSI" target.
The only value I see is that the initiator doesn't have to find the name
first.  But the target will need to "correct" that name in response anyway
(at which point it has a name which it can use for all other sessions) --
it could/should be a one time deal, probably, to go through the discovery
(SendTargets) step.  I don't think we really want the host to think that it
has any number of real targets all named "iSCSI"!

Jim Hafner


Mark Bakke <mbakke@cisco.com>@ece.cmu.edu on 05-16-2001 12:14:35 PM

Sent by:  owner-ips@ece.cmu.edu


To:   Stephen Bailey <steph@cs.uchicago.edu>
cc:   ips@ece.cmu.edu
Subject:  Re: iSCSI: Canonical Targets



That kind of makes sense.  If we limit SendTargets to the discovery
session, and disallow SCSI commands to the discovery session, then
we really don't have a target at all from SCSI's point of view; but
we do have a "special" target from iSCSI's point of view since we
are doing the full login to it.

So if we used

  TargetName=

we would get the discovery target; if we used

  TargetName=iSCSI    # Note: this is case-insensitive

we would get whatever default target the iSCSI device wanted
our initiator to see.  Even if we do end up supporting both, I
guess I'd rather see a target name, rather than leaving it
blank.  How about

   TargetName=discovery

BTW, nobody else has spoken up for having this default target
that would avoid having to use SendTargets if there were not
multiple targets available to an initiator.

Who plans to make use of this?  I don't mind putting it in
(we had sort of implied the functionality before), but if
it is not in anyone's plans, I'd rather go for a simpler spec.

Stephen Bailey wrote:
>
> > Any other ideas?
>
> My suggestion was to not supply any target name for a discovery login
> (which is how a discovery login would be distinguished) and call
> `iSCSI' the `default' (operational) target.
>
> Steph

--
Mark A. Bakke
Cisco Systems
mbakke@cisco.com
763.398.1054