Device Identification VPD Page - iSCSI

Knight, Frederick Frederick.Knight at netapp.com
Fri Apr 27 11:37:20 PDT 2007


* From the T10 Reflector (t10 at t10.org), posted by:
* "Knight, Frederick" <Frederick.Knight at netapp.com>
*
I agree with Bob, that this makes no sense.  The spec clearly describes
the intent of these fields (again from SPC2):
"Operating systems are expected to use the device identifiers during
system configuration activities to determine whether alternate paths
exist for the same peripheral device."
It also says:
"The device identification page (see table 170) provides the means to
retrieve zero or more identification descriptors applying to the logical
unit."
Both from section 8.4.4 of SPC2.
So while I would say this device meets the letter of the law, it does
not meet the intent.  It is legal to provide useless data in these
fields, but then those fields can not be used for what they are intended
to be used for, so it's kind of problematic to meet the letter of the
law, but then not work when a host tries to use the data.
It may have been stuff like this that led to the language change in the
SPC3 and SPC4 specs.
Bob is right, the device needs to be fixed.
	Fred Knight
-----Original Message-----
From: Robert Snively [mailto:rsnively at brocade.com] 
Sent: Thursday, April 26, 2007 12:07 PM
To: Mike Berhan; t10 at t10.org
Subject: RE: Device Identification VPD Page - iSCSI
* From the T10 Reflector (t10 at t10.org), posted by:
* "Robert Snively" <rsnively at Brocade.COM>
*
It may be that you are working with a Beta model that has not had its
WWN installed yet.  If that is the case, NAA=0000 (meaning "Name Not
Present") might be appropriate for the device.	However, it would not be
compliant, because "Name Not Present" is not a world-wide unique name.
Sounds like it is time to contact the iSCSI device manufacturer and get
an update that correctly defines the name.
Bob 
-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Knight,
Frederick
Sent: Thursday, April 26, 2007 6:36 AM
To: Mike Berhan; t10 at t10.org
Subject: RE: Device Identification VPD Page - iSCSI
* From the T10 Reflector (t10 at t10.org), posted by:
* "Knight, Frederick" <Frederick.Knight at netapp.com>
*
The SPC2 spec contains the following wording in section 8.4.4 for
Identifyer types 3h (the NAA type in SPC3/4):
"The identifier field contains an FC-FS Name_Identifier. Any FC-FS
identifier may be used, including one of the four based on a Canonical
form IEEE company_id."
Even the SPC3 spec says in section 7.6.4.5.1 - "This format is
compatible with the Name_Identifier format defined in FC-FS."
So at minimum, the device is SPC2 compliant ("Any FC-FS identifier may
be used...").
	Fred Knight
	Network Appliance
	RTP,  NC
-----Original Message-----
From: Mike Berhan [mailto:mikeb at bustrace.com]
Sent: Wednesday, April 25, 2007 5:25 PM
To: t10 at t10.org
Subject: Device Identification VPD Page - iSCSI
* From the T10 Reflector (t10 at t10.org), posted by:
* "Mike Berhan" <mikeb at bustrace.com>
*
Table 356, in SPC-4 Revision 10, defines the NAA Designator field.  The
first four bits (bits 7-4) of this field indicate the Name Address
Authority (NAA).  Table 357 shows three defined values:
2h  IEEE Extended
5h  IEEE Registered
6h  IEEE Registered Extended
In other specifications (e.g. FC-FS), I have found the Name_Identifier
define additional NAA values.  For example:
0h  Ignored
1h  IEEE 48-bit Address
2h  IEEE Extended
3h  Logically Assigned
4h  32-bit IP Address
5h  IEEE Registered
6h  IEEE Registered Extended
Remaining Reserved
Are SPC-4 compliant devices allowed to return NAA values other than 2,
5, or 6.  If so, should Table 357 show the additional values?
The reason I ask is that I am debugging an iSCSI device that is
returning an NAA value of 0 (Ignored) and I am trying to determine if
this device is
SPC-3/4 compliant.  Thank you.
-------
Mike Berhan
busTRACE Technologies
9700 Village Center Drive
Suite 50-F
Granite Bay, CA  95746
916.773.4554 phone
916.218.6283 fax
http://www.bustrace.com
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