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Subject: RE: iSCSI: Login Redirect
Date: Tue, 15 Jul 2003 10:51:12 -0700
Message-ID: <9941CD424AF2074DA4674E972D2FCDB4056A1C@troy.intransa.com>
Thread-Topic: iSCSI: Login Redirect
Thread-Index: AcNK9JEUXRJREsZTRwW505fbJl8fyAABBXiw
From: "Rajkumar Velpuri" <rajkumar.velpuri@intransa.com>
To: "Mallikarjun C." <cbm@rose.hp.com>,
	"Lakshmi Ramasubramanian" <nramas@windows.microsoft.com>,
	<ips@ece.cmu.edu>
Sender: owner-ips@ece.cmu.edu
Precedence: bulk


The Gilligan draft submitted to IPS working group in March describes
using login re-direct for load balancing and failure recovery.

The proposal in Gilligan draft was addressing issues not described in
iSCSI draft.  I believe Lakshmi's question fits into that context.

Raj Velpuri

-----Original Message-----
From: Mallikarjun C. [mailto:cbm@rose.hp.com]=20
Sent: Tuesday, July 15, 2003 10:14 AM
To: Lakshmi Ramasubramanian; ips@ece.cmu.edu
Subject: Re: iSCSI: Login Redirect

If this mis-direction is going on to different portals within
the same target node, I would think that it implies a serious
configuration issue within the target node because it either
does not have a global node-level view of the iSCSI service
it offers, or the situation is changing too rapidly to be correct.

If on the other hand, this mis-direction is forcing an=20
initiator to shuttle to different target nodes, it usually implies a
lack of a consistent SAN-level view among the target nodes
that are supposed to be doing cooperative redirection (which
is what the feature was meant for).

In either case, I tend to think that the issue is one of implementation/
configuration and placing hard limits on the # of redirections in
the spec is neither reasonable nor enforceable.   I believe that the=20
spec doesn't preclude implementations from having a limit (for ex., the=20
initiator iSCSI may decide to give up the chase after X attempts and=20
report a failure to its ULP).
--
Mallikarjun

Mallikarjun Chadalapaka
Networked Storage Architecture
Network Storage Solutions
Hewlett-Packard MS 5668=20
Roseville CA 95747
cbm@rose.hp.com

----- Original Message -----=20
From: "Lakshmi Ramasubramanian" <nramas@windows.microsoft.com>
To: <ips@ece.cmu.edu>
Sent: Tuesday, July 15, 2003 8:51 AM
Subject: iSCSI: Login Redirect


When a target is moved (Temporary or Permanent), target
sends an appropriate status code and gives the new target
address. Is there a limit on the number of times a target
can redirect login? If not, should we have one?
=20
    Initiator logs into Portal A.=20
    Target redirects to Portal B.
    Initiator logs into Portal B.=20
    Target now redirects to Portal C.
    And so on...
=20
Should we have an upper limit on the number of times a target
can redirect the login?
=20
thanks!
 -lakshmi