Hi, Shawn, sorry to be slow in
responding, but as you pointed out, it's vague in the standads that
apply (FCP-3/4 and FC-LS), and I ahd to struggle to find anything. In
the end, I came to the same conclusion as Kevin Butt about intent.
There is some hint in both
standards that a PLOGI in the presense of an existing N_Port Login is
traumatic: In FCP-4 table 7, the columns for PLOGI and PRLI are the
same as the ones for LOGO and PRLO.
In FC-LS concerning PLOGI, the
third paragraph of subclause 6.3.2.1 requires treatment of new
Sequences "as though a Logout had been performed". From the standpoint
of FC-LS, this is essentially equivalent to an implicit logout, since
FC-LS and FC-FS-3 specify no persistent behavior that is not either
renegotiated by PLOGI or reflected in the collection of open Sequences.
Concerning PRLI, FC-LS insists
on the next to last paragraph on page 180 (printed numbering) that it
does NOT imply Process Logout; however, the last paragraph suggests the
iimpact is similar if Service Parameters are changed. FCP-3/4 would
appear to override this, at least in part.
You're right that some
clarification would be nice. I suspect that FC-LS-2 needs to
explicitly say that a PLOGI causes implicit logout of any existing
N_Port Login with the same N_Port, and FCP-4 should say that
PRLI causes I_T nexus loss if it changes existing FCP-4 Service
Parameters. Others on this reflector may be able to make a better
statement. Would you like to propose text for FCP-4 and/or FC-LS-2?
Would you like me to?
- bob nixon (secretary for
FCP-4 and FC-LS-2)
A big thank you to all who responded! I was just wondering if anyone
may know where I can reference the situations which cause an implicit
LOGO/PRLO, or maybe is this a better question to ask T11? FC-LS-2
section 6.4.4 seems to be vague on the issue, and doesn't mention this
case.
Thanks,
--
Shawn Authement
Sr. Software Engineer
Texas Memory Systems, Inc.
Shawn.Authement@texmemsys.com
ph: +1.713.266.3200
Kevin D Butt wrote:
Shawn,
Yes, when an N_Port performs a
PLOGI/PRLI it logs in again. This can be viewed as an implicit
LOGO/PRLO and as stated in 4.11 of FCP-4 (http://www.t10.org/ftp/t10/drafts/fcp4/fcp4r01.pdf) this generates an I_T nexus loss
notification.
Regards,
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/
* From the T10 Reflector (t10@t10.org), posted by:
* Shawn Authement <Shawn.Authement@texmemsys.com>
*
All,
I am currently researching device behavior with respect to N_Port login
and was wondering if anyone can provide clarification.
Q: If an already-logged-in N_Port performs login again (via PLOGI), is
this considered an I_T nexus loss as defined by SAM-3, 6.3.4?
The ENDL Fibre Channel Bench Reference implies that re-Login causes an
implicit Logout. However, I cannot find any supporting information in
either the FCP-3 for FC-LS specifications. My goal is to ultimately
determine whether a SCSI Target Port should set a Unit Attention if a
SCSI Initiator Port re-logs in.
Thank you for your your help!
--
Shawn Authement
Sr. Software Engineer
Texas Memory Systems, Inc.
Shawn.Authement@texmemsys.com
ph: +1.713.266.3200
*
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