RE: iSCSI: Use of Reject as a key value

[kevin_lemay@agilent.com]

The iSCSI spec did not specify the handling of reject prior to the current v15 working version.

I am NOT proposing changing the case sensitivity.

I am merely pointing out a potential problem in the proposed handling of reject during login negotiation.

Our current implementation handles it as described by Professor Russell as "Case 2", the rejection of a parameter during login (except for markers) terminates the login.

My example was meant to demonstrate the problem associated with continuing the login with rejected parameters. The initiator and target have the potential to continue with miss-matched parameters.

Professor Russell had three proposals in what he posted. He was not requesting a particular wording but meant to open it up to the list for discussion and a solution.

Kevin

-----Original Message-----
From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Friday, July 26, 2002 1:33 AM
To: kevin_lemay@agilent.com
Cc: ips@ece.cmu.edu; Julian Satran; pat_thaler@agilent.com;
rdr@io.iol.unh.edu
Subject: RE: iSCSI: Use of Reject as a key value


Do you propose the formulate the standard so that it can tolerate all
initiator syntax errors? Or just we state that it should be case
insensitive.
The first would be a bad idea. The protocol has enough complexity in order
to deal with transport errors. It would be a bad idea to add
implementation errors to the list.
If you want case insensitivity - this was discussed and rejected a long
time ago - again because it felt unnecessary.

I would also like to point out that this is not a change. This behavior was
always assumed (and implied in the statements about negotiations
atomicity).
The statement was added at the request of Bob Russell as a clarification.

Julo




                                                                                                                                            
                      kevin_lemay@agile                                                                                                     
                      nt.com                   To:       Julian Satran/Haifa/IBM@IBMIL, rdr@io.iol.unh.edu                                  
                                               cc:       ips@ece.cmu.edu, pat_thaler@agilent.com                                            
                      07/25/2002 09:59         Subject:  RE: iSCSI: Use of Reject as a key value                                            
                      PM                                                                                                                    
                                                                                                                                            
                                                                                                                                            



Julian,

I think that this change is a bad idea.

The spec says that:

"If the acceptor sends "Reject" as an answer the negotiated key is left at
its current value (or default if no value was set). If the current value is
not acceptable to the proposer on the connection or session it is sent the
proposer MAY choose to terminate the connec- tion or session."

But what happens in the following case:

i->ImmediateData=Yes
t->ImmediateData=no (Note: wrong case used)

The initiator must use the default, which is ImmediateData=Yes, and there
is no way for the initiator to inform the target of the error because
sending:
i->ImmediateData=Reject would be a re-negotiation.

This will not work!

Kevin

-----Original Message-----
From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
Sent: Wednesday, July 24, 2002 7:52 PM
To: Robert D. Russell
Cc: ips@ece.cmu.edu; owner-ips@ece.cmu.edu
Subject: Re: iSCSI: Use of Reject as a key value



Bob,

On the last pdf you will find a statement about what to do.

Julo



             "Robert D. Russell" <rdr@io.iol.unh.edu>
Sent by: owner-ips@ece.cmu.edu


07/25/2002 12:58 AM



        To:        ips@ece.cmu.edu
        cc:
        Subject:        iSCSI: Use of Reject as a key value







Julian:

Attached are 2 ascii text files.

The first, reject_extracts.txt, contains all the pieces of
draft 14 (the latest available txt version of the drafts)
that say anything about the use of Reject as a key value.
(At least all those I could find using simple search --
unfortunately, Reject is also the name of a PDU and hence
it is not a simple mechanical process to distinguish the two
uses!  If I missed some, please let me know.)

The second, reject_comments.txt, are my comments on these
excerpts from the standard.

It seems to me that the key thing missing in the standard is
a general statement about "what to do next" if a key=Reject response
is received.  Except for the OFMarkInt and IFMarkInt keys,
I could find no other statement about how to proceed after
receiving the key=Reject response.  In looking through the
e-mails posted to the list for June and July, I also could find
nothing, although many people seem to be taking the third
of the 3 interpretations I listed in reject_comments.txt.

I am requesting a clear statement somewhere in the standard that
says "what to do next" upon receiving a key=Reject response.

Thank you for your consideration.

Bob Russell
InterOperability Lab
University of New Hampshire
rdr@iol.unh.edu
603-862-3774







#### reject_extracts.txt has been removed from this note on July 25 2002 by
Julian Satran
#### reject_comments.txt has been removed from this note on July 25 2002 by
Julian Satran