Subject: new iSCSI PDU outline

From: [email-masked]
Date: Thu, 25 Jan 2001 18:58:37 +0200

Dear all,

Here is the new outline.

Julo

(See attached file: iSCSI-PDU-outline.txt)

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From: "Douglas Otis" <[email-masked]>
Date: Thu, 25 Jan 2001 14:41:02 -0800

Julian,

Would you consider splitting headers.  As was done with MTF, there was just
a simple 32 bit simple XOR checksum for header fields.  Here is an example
with a CDB appended.  The WN could expand the appended type into SCSI_CMND,
SCSI_RSP, SCSI_R2T, iSCSI_Specific, etc.

  |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| WN            | Reserved                      | AddCDB        |
  +---------------+---------------+---------------+---------------+
 4| Length                                                        |
  +---------------+---------------+---------------+---------------+
 8| ->CmdSN or <-StatRN                                           |
  +---------------+---------------+---------------+---------------+
12| ->ExpStatSN or <-ExpCmdSN                                     |
  +---------------+---------------+---------------+---------------+
16| ->MaxStatRN? <-MaxCmdSN                                       |
  +---------------+---------------+---------------+---------------+
20| XOR Checksum                                                  |
  +---------------+---------------+---------------+---------------+
  +---------------+---------------+---------------+---------------+
24| SCSI_CMND  ...                                                |
  +-                                                              |
32|                                                               |
  +---------------+---------------+---------------+---------------+
36| CDB ...                                                          |
  +---------------+---------------+---------------+---------------+
x | (Data ...)                                                         |
  +---------------+---------------+---------------+---------------+
y | CRC                                                           |
  +---------------+---------------+---------------+---------------+

Doug

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From: Matt Wakeley <[email-masked]>
Date: Tue, 30 Jan 2001 02:07:33 -0800

Julian,

Section 2.2.1, bits 6-4:

I think you forgot the BHS structure in the encodings

Also, why do we (you) want the long data header??? we already have 32 bits of
length, what in the world would we want 64 bits of length for???

Section 2.3 - I don't see how you made it 44 bytes from 48 without eliminating
any fields...?  looks like you cut the CDB from 16 to 12 bytes...

I don't understand 2.2.1, bit 7:  0=another header, and 1=no header, only
data?

You should specify that bits 1-0 only are valid if bit 7 indicates no header

In other words, within each WN, you are specifying if the there is another WN,
if not, then (implies data) you specify the digest of the data.

-Matt