Subject: RE: iSCSI Naming: WWUIs, URNs, and namespaces

From: "Thomas McSweeney" <[email-masked]>
Date: Wed, 11 Apr 2001 09:13:49 -0400

Marjorie,
                                                                      
 >The host name provides the level of uniqueness necessary            
 >to allow iSCSI to ensure further uniqueness within that host.       

Not all iSCSI devices have a host name;  some use DHCP for IP address
assignment, particularly initiators.  An initiator needs a name that is
more unique than just within its host, so the target can identify it
(imagine all the initiators named "WindowsLaptop").  It is even possible
for a target to use DHCP, if all the initiators find its IP address using
some means other than DNS (e.g., iSNS and/or SLP).  Also, this would enable
storage administrators to configure a "hot backup" of a target on a second
host, so they can temporarily move the data to a backup machine to perform
some maintenance on the primary machine, without reconfiguring the
potentially thousands of geographically widespread initiators.  You could
preconfigure the initiators with a primary hostname and a backup hostname
for the target, or use iSNS/SLP to learn its IP address.

Tom McSweeney
iSCSI Development, Storage Systems Group, IBM
Email: [email-masked]
Phone: (USA) 919-254-5634  (tie line: 444-5634)
Fax:   (USA) 919-254-0391  (tie line: 444-0391)

---

From: Brian Pawlowski <[email-masked]>
Date: Wed, 11 Apr 2001 11:01:46 -0700 (PDT)

Wait.

Are "initiators" being connected to actively by "targets"?
Via some call back or something?

I might be missing something here - I was doing a mental analogy
to NFS clients and servers - we had to come up with a server
name space, but the clients were initiating the mappings and
only had to be able to find file systems on servers (forming
an identifier).

---

From: "Douglas Otis" <[email-masked]>
Date: Wed, 11 Apr 2001 13:44:02 -0700

Brian and Marjorie,

There is a need to obtain iSCSI configuration information in a generalized
way.  This information should allow the client to find the server using
existing IP namespace information.  Forging connections within the server
must use normal SCSI naming appended in some manner to the IP namespace.
The SCSI naming should not be dereferenced to require an additional name
server.  DHCP provides a standard means of indicating the location of LDAP.
SLP also provides a standard means of locating LDAP.  There is a standard
alias convention of ldap.example.com of finding the LDAP server and LDAP has
be working with may security schemes for years.  Once an LDAP schema is
defined by the IPS group, then any Directory User Agent can obtain any
auxiliary information without the need for yet another name server.

Marjorie had mentioned that some are considering XML to support this
function.  You will need some way to find this service.  You will find
little information regarding security and w3c.org conventions for naming are
system not public based as I had mentioned.  Security issues regarding XML
will be addressed.  Microsoft has announced their secure version of NT (XP)
will use XML to manage updates through third parties.  I bet this will be as
popular as Clippit.  With the desire to invent a new name server, XML
namespace seems a likely bet.  It will be interesting to see if all this can
be made secure.  It is a goal of Microsoft obviously and will keep w3c.org
busy for many years.  It does seem rather bold to base management on such
new code for something so critical.

Doug