Subject: iSCSI version 0.6 - Query?

From: "Tanjore K. Suresh" <[email-masked]>
Date: Sat, 9 Jun 2001 22:25:35 -0700 (PDT)

Hi,

Page 12, Last paragraph.

Regarding the command sequence number.

" The target MUST silently *ignore* any command outside this range or
duplicates with in the range that have not been flagged with the retry bit 
(the X bit in the opcode)"

Why ignore commands which are not in the expected range or duplicates
with in the range? This type of ignoring could  cause initator to
cause some unnecessary recovery activity which could/may end up to
be not good for the target which is hale and healthy. 

Such a  command could have been errorneously numbered or errorneously 
checked for this condition or errnoneously delivered with  sequence 
number change because of problems  transporting it over the internet fabric.

Hence, my opinion is appropriate error need to be returned for such command
instead of ignoring. 

Comments?

Thanks
sureshtk

I

---

From: "Robert Griswold" <[email-masked]>
Date: Wed, 13 Jun 2001 12:27:49 -0500

This is a very good question.  If "silently ignore" means that at the
time of receipt the target should not attempt to qualify the receipt of
the command at the time it received it, but instead attempt to resolve
this after the MaxCmdSN has been sent, then I would say it makes sense,
but your question interests me with regards to recovery.  Since section
6.1 requires Targets to reject PDUs in a session with format errors
(assuming a misaligned CmdSN constitutes a format error) then it would
seem that this section on page 12 is not in agreement with recovery.
But, the recovery section also leaves the door open for Target mode
implementation on recovery, so if the paragraph on page 12 over-rides
the recovery section, it must be up to the implementer of the Target to
attempt to recover such a misaligned command?

Bob

Robert Griswold
Technologist
Crossroads Systems, Inc.
512-928-7272

 -----Original Message-----
From: 	Tanjore K. Suresh [mailto:[email-masked]] 
Sent:	Sunday, June 10, 2001 12:26 AM
To:	[email-masked]
Subject:	iSCSI version 0.6 - Query?

Hi,

Page 12, Last paragraph.

" The target MUST silently *ignore* any command outside this range or
duplicates with in the range that have not been flagged with the retry
bit 
(the X bit in the opcode)"

Such a  command could have been errorneously numbered or errorneously 
checked for this condition or errnoneously delivered with  sequence 
number change because of problems  transporting it over the internet
fabric.

Hence, my opinion is appropriate error need to be returned for such
command
instead of ignoring. 

Comments?

Thanks
sureshtk

I