RE: iSCSI: Negotiation clarifications still needed

[pat_thaler@agilent.com]

Bill,

I don't think that we need to prevent that case. If the initiatior chooses to 
not initiate a key-value pair when it has received a partial key-value pair
(or a partial key) and it doesn't have any keys to respond to, then it can
continue the negotiation by sending a PDU with the tail of the partial key-value
that it sent. Even if it doesn't have a partial key-value to send it can send
a PDU with a blank text field. Either way, the target can then send another 
PDU finishing its partial key-value. 

This isn't broken so we don't have to change it to make iSCSI robust.

Pat

-----Original Message-----
From: Bill Studenmund [mailto:wrstuden@wasabisystems.com]
Sent: Friday, May 24, 2002 5:42 PM
To: pat_thaler@agilent.com

<snip>
But there's another case too:

Say the response from the target ALSO doesn't fit in one PDU. Yes, the
target's not going to respond to the key=value pair that wasn't complete,
but say its response to everything else was bigger than the initiator's
representation of said keys. For this case to happen, the target's
response has to grow more than the first bit of the PDU-spanning key/value
pair.

The case where I can see this happening is we had a mix of boolean-or keys
and other keys. And for these bolean-or keys, the initiator wanted NO but
the target wanted YES. So the target's response is bounded to be bigger.
Or maybe there were some Rejects in there when the offer was less than 7
bytes long.

So now we have TWO PDU-spanning key sets. And the target didn't originate
anything. :-)

Yes, this is a rare case. But it can happen. And, for iSCSI to be robust,
we need to prevent it.