RE: new iSCSI PDU outline

[julian_satran@il.ibm.com]

Doug,

You are right and we could do it but it will reduce the number of yet
unallocated types in WN (and T10 is adding more stuff to the SCSI!) and
will save us several bits in the command where we have plenty. I don't
think it is worth it.

Regards,
Julo

"Douglas Otis" <dotis@sanlight.net> on 26/01/2001 00:41:02

Please respond to "Douglas Otis" <dotis@sanlight.net>

To:   Julian Satran/Haifa/IBM@IBMIL, ips@ece.cmu.edu
cc:
Subject:  RE: new iSCSI PDU outline




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