Re: iSCSI: Wrapping up SendTargets

[Mark Bakke <mbakke@cisco.com>]

David-

Your comments wrap this up from my point of view.  We'll
add:

   A SendTargets response MUST NOT include other "canonical"
   targets.  This prevents an initiator from using SendTargets
   recursively, and getting into loop problems.

This will keep things clean enough, and we don't have to
disallow implementations from doing what Marjorie had wanted,
and that Glen had provided another decent argument for.

I'll post a new SendTargets section RSN.

--
Mark

Black_David@emc.com wrote:
> 
> > I don't see any reason to disallow what Marjorie is asking
> > for.  However, we should also decide whether or not a SendTargets
> > response may contain a well-known/default/canonical target to
> > which the initiator is expected to recursively issue a
> > SendTargets command.
> >
> > Supporting that feature is much more likely to be a problem
> > if we want implementations to transition to other discovery
> > mechanisms in the future, as well as creating requirements to
> > avoid loops.
> >
> > Any thoughts?
> 
> On further thought, I agree.  Forbidding recursive use
> of SendTargets prevents the nasty problem scenarios such as
> recursion problems/bugs that prevent discovery of things that
> should have been discovered and loops in the recursion structure.
> 
> This prohibition is easy to specify - Initiators won't do the recursion,
> hence SendTargets MUST NOT return information about other
> canonical targets.  IMHO, this is sufficient, and the tighter
> restriction based on same <IP address, TCP port> is not
> needed.  If someone wants to have SendTargets return
> information about multiple systems, keeping that information
> correct and up to date across the systems is their
> problem, not ours (long version of "Marjorie was right").
> 
> Thanks,
> --David
> ---------------------------------------------------
> David L. Black, Senior Technologist
> EMC Corporation, 42 South St., Hopkinton, MA  01748
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-- 
Mark A. Bakke
Cisco Systems
mbakke@cisco.com
763.398.1054