iSCSI : Negotiable padding, was More issues.... Digest related.

["Rod Harrison" <rod.harrison@windriver.com>]

Julian,

	I have a request with respect to data padding. Can we make
the pad size login negotiable please? Preferably on a per
direction basis. This would allow the pad to be optimized
for a receivers specific requirements, e.g. cache line
alignment. Restricting padding to powers of 2 by specifying
the size as a power of 2 seems reasonable.

	For example:

	IPadSize=<any-power-of-two>
	TPadSize=<any-power-of-two>

	IPadSize=0
	TPadSize=2

	Would result in the initiator padding data to 4 byte
boundaries for the target, and the target inserting no pad
for the initiator.

	Also, a related question, if the pad is to remain mandatory
is it expected data will be padded if no data digests are in
use?

	- Rod

-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On
Behalf Of
julian_satran@il.ibm.com
Sent: Friday, April 20, 2001 1:45 AM
To: ips@ece.cmu.edu
Subject: Re: iSCSI : More issues.... Digest related.




1.The padding is to the next 4 byte word boundary .
2. There is a Security - Appendix

and there is a numbering /formating error in the appendix

Julo

Santosh Rao <santoshr@cup.hp.com> on 20/04/2001 03:25:49

Please respond to Santosh Rao <santoshr@cup.hp.com>

To:   IPS Reflector <ips@ece.cmu.edu>
cc:
Subject:  iSCSI : More issues.... Digest related.




Julian & All,

2 more issues :

1) If the DataSegmentLength in the BHS excludes padding
bytes, how does
the initiator determine the location of the data digest
[which is placed
after the padded data] ?
There is no knowledge of what amount of padding is in use,
since padding
can be 4 bytes or a multiple of that quantity.


2) While on the subject of digests.....are'nt there supposed
to be
login keys to indicate the use or non-use of header and data
digests ? I
can't seem to find any such login keys in the latest revs
5.91....5.92....6.000...(?)

(Section 2.2.1 states :
"The digest types are negotiated during the login phase. ").

- Santosh
 - santoshr.vcf