Subject: iSCSI - change - parameter segregation

From: "Julian Satran" <[email-masked]>
Date: Sun, 26 Aug 2001 09:31:13 +0300

According to the consesus reached on this list to attempt to segregate (if
possible) SCSI mode page parameters that are iSCSI specific or have an
"iSCSI flavor/interpretation" I suggest the following new version for
chapter 3:

1.   SCSI Mode Parameters for iSCSI

   This chapter describes fields and mode pages that control and report the
   behavior of the iSCSI protocol. All fields not described here MUST
   control the behavior of iSCSI devices as defined by the corresponding
   command set standard.

   The iSCSI specific parameter change MUST be performed following the SCSI
   rules as stated by [SAM2] and [SPC].

1.1  SCSI Disconnect-Reconnect Mode Page use in iSCSI

   The following outlines the SCSI Disconnect-Reconnect mode page usage for
   iSCSI:

   Byte /    0       |       1       |       2       |       3       |
      /              |               |               |               |
     |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
     +---------------+---------------+---------------+---------------+
    0|P|0| 0x02      | 0x0e          | Reserved(0)                   |
     +---------------+---------------+---------------+---------------+
    4| Reserved (0)                                                  |
     +---------------+---------------+---------------+---------------+
    8| Reserved (0)                  | MaximumBurstSize              |
     +---------------+---------------+---------------+---------------+
   12|E| Reserved (0)                | FirstBurstSize                |
     +---------------+---------------+---------------+---------------+

1.1.1     MaximumBurstSize Field (16 bit)

   This field defines the maximum SCSI data payload in an iSCSI sequence (a
   sequence of Data-In or Data-Out PDUs ending with a Data-In or Data-Out
   PDU with the F bit set to one) in units of 512 bytes.

1.1.2     E - Enable Modify Data Pointers Bit (EMDP)

   Data PDU Sequences (a sequence of Data-In or Data-Out PDUs ending with a
   Data-In or Data-Out PDU with the F bit set to one) can be in any order
   (EMDP = 1) or at continuously increasing addresses (EMDP = 0).

1.1.3     FirstBurstSize Field (16 bit)

   This field defines the maximum amount of unsolicited data an iSCSI
   initiator may to send to the target in units of 512 bytes.

1.1.4     Other Fields

   No other fields in this page are used by iSCSI.

1.2  iSCSI Logical Unit Control Mode Page

   The following outlines the iSCSI Port mode page:

   Byte /    0       |       1       |       2       |       3       |
      /              |               |               |               |
     |7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|7 6 5 4 3 2 1 0|
     +---------------+---------------+---------------+---------------+
    0|P|0| 0x18      | 0x02          | 0x05          | Reserved (0)|C|
     +---------------+---------------+---------------+---------------+

1.2.1     Enable CRN (C)

   When C is set to 1 the CRN field is considered by LU.

 DataPDULength (in appendix D) becomes:

01   DataPDULength

   Use: LO
   Who can send: Initiator and Target

   DataPDULength=<number-0-to-(2**15-1)>

   Default is 16 units.

   Initiator and target negotiate the maximum data payload supported for
   SCSI command or data PDUs in units of 512 bytes. The minimum of the 2
   numbers is selected.

   A value of 0 indicates no limit.

 FirstBurstSize (in Appendix D) is removed.
 DataSequenceOrder (in Appendix D) is removed

 Comments?

 Julo