Date: Thu, 30 Oct 2008 11:58:47 -0500 From: Shawn Authement <Shawn.Authement@texmemsys.com> To: t10@t10.org CC: Bob.Nixon@emulex.com Subject: Re: I_T nexus loss X-Message-Number: 9248 Formatted message: HTML-formatted message I am finally able to spend some time on this issue of I_T nexus loss. One thing in your response Bob was that "PRLI causes I_T nexus loss if it changes existing FCP-4 Service Parameters". What if it doesn't change them (i.e., the given service parameters are equivalent to the previous service parameters? To re-cap, I am investigating the following scenario: o Nx_Port (A) (already logged in) sends PLOGI sequence with the same exact service parameters as the original login o Nx_Port (B) sends LS_ACC o Nx_Port (A) sends PRLI with the exact same service parameters as the original login o Nx_Port (B) sends LS_ACC o Nx_Port (A) sends TEST UNIT READY As this point, does Nx_Port (B) send back a status of CHECK CONDITION, a sense key of UNIT ATTENTION, and an additional sense code (qualifier) of I_T NEXUS LOSS HAS OCCURRED? Thanks! -- Shawn Authement Sr. Software Engineer Texas Memory Systems, Inc. Shawn.Authement@texmemsys.com ph: +1.713.266.3200 Bob.Nixon@Emulex.Com wrote: > 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) > > > > ------------------------------------------------------------------------ > *From:* owner-t10@t10.org [mailto:owner-t10@t10.org] *On Behalf Of > *Shawn Authement > *Sent:* Wednesday, October 01, 2008 9:31 AM > *To:* t10@t10.org > *Subject:* Re: I_T nexus loss > > 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: Shawn Authement <Shawn.Authement@texmemsys.com> > To: t10@t10.org > Date: 09/24/2008 12:17 PM > Subject: I_T nexus loss > > > ------------------------------------------------------------------------ > > > > * 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 > > * > * For T10 Reflector information, send a message with > * 'info t10' (no quotes) in the message body to majordomo@t10.org > > >