RE: iSCSI: keys/parameter dependence

[Robert Snively <rsnively@Brocade.COM>]

I stand corrected.  If you want to order batches, you must
not only transmit the keys that you want to batch, but you must
also not transmit another batch of keys until you have received the
replies for the outstanding batch.

You must also do this in a manner consistent with the 
stage of login or post-login operation that is being performed,
as specified in 4.3.  

I haven't studied all aspects of this carefully, but I would
expect that the processing must proceed on a batch by batch
basis, since it is never clear when the Final-Response exchange
will be requested and the target must have completed whatever
negotiation is going on with respect to previous batch exchanges.
I would not expect the target to be allowed to hang around doing nothing
until Final-Response exchanges were requested.  This seems to be
what section 4.4 says, at least for post-login activities.

I was a little surprised to see that post-login negotiations of
a parameter a second time without an intervening reset 
constitute a protocol error.  Some of the values, notably
those duplicating MODE SENSE/SELECT parameters, have traditionally
been renegotiable as desired by the SCSI device without an
intervening reset, and I would expect that capability to have
been mapped into the key=value negotations.

Bob

> 
> Is this true?  When the C bit is not set, there appears to be
> no requirement in the standard that the receiver is forced to
> reply to the keys it has received at that time -- it MUST reply
> to every key eventually, but just having the C bit = 0 does
> not seem to require it to reply then -- it could send an empty
> reply PDU, or could offer new keys of its own at that time
> and delay responding to anything until "everything is on the
> table".  Comments/corrections please.