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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI - opcodesJulian, I am not sure what decision was taken on this, but I would also vote for having the direction bit as the MSB (bit-5) in the opcode. -Ayman > -----Original Message----- > From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of > julian_satran@il.ibm.com > Sent: Monday, May 28, 2001 6:54 AM > To: ips@ece.cmu.edu > Subject: RE: iSCSI - opcodes > > > > > The new codes are in the 07 draft. Although I've put back the bit that > shows direction I seriously doubt that > it's original purpose (to make life easier for analyzers) is as > relevant as > it was. > > Julo > > "Martin, Nick" <Nick.Martin@compaq.com> on 01-05-2001 01:48:00 > > Please respond to "Martin, Nick" <Nick.Martin@compaq.com> > > To: Julian Satran/Haifa/IBM@IBMIL > cc: > Subject: RE: iSCSI - opcodes > > > > > Julian, > > I was not among the incensed. I would say puzzled. Although the bit may > not be not critical to initiators or targets who presumably know what they > are, it is handy at least for network analyzer displays. > > Since it now still consumes a bit, I would have made it the MSB of the > Opcode field as in previous drafts (currently bit 5 or 0x20). However I > can > cope with your selection ((Opcode & 0x3e)>>1) :). > > The 2F reject instead of 3F (or 1f) for reject was another puzzler. > Presumably you wanted a fence between unused reserved opcodes and vendor > specific codes. > > Thanks, > Nick Martin > > -----Original Message----- > From: julian_satran@il.ibm.com [mailto:julian_satran@il.ibm.com] > Sent: Friday, April 27, 2001 12:38 AM > To: ips@ece.cmu.edu > Cc: matt_wakeley@agilent.com > Subject: iSCSI - opcodes > > > > > Fellow iSCSI fans, > > Some were incesed by the lak of a "direction bit" in the opcodes in draft > 06. > Here is an attempt to a new list (having a bit for direction back - as the > LSB ). > To gain some reserved space I've curtailed the vendo-specific > codes to 4 in > each direction. > > > Please comment, > Julo > > 1.1.1.1 Opcode > > The Opcode indicates what type of iSCSI PDU the header encapsulates. > > The Opcodes are divided into two categories: initiator opcodes and > target opcodes. Initiator opcodes are in PDUs sent by the initiators > (request PDUs), and target opcodes are in PDUs sent by the target > (response PDUs). > > Initiators MUST NOT use target opcodes and targets MUST NOT use > initiator opcodes. > > Valid initiator opcodes defined in this specification are: > > > 0x00 NOP-Out (from initiator to target) > 0x02 SCSI Command (encapsulates a SCSI Command Descriptor Block) > 0x04 SCSI Task Management Command > 0x06 Login Command > 0x08 Text Command > 0x0a SCSI Data-out (for WRITE operations) > 0x0c Logout Command > 0x10 SNACK Request > > Valid target opcodes are: > > > 0x01 NOP-In (from target to initiator) > 0x03 SCSI Response (contains SCSI status and possibly sense > information or other response information) > 0x05 SCSI Task Management Response > 0x07 Login Response > 0x09 Text Response > 0x0b SCSI Data-in (for READ operations) > 0x0d Logout Response > 0x11 Ready To Transfer (R2T - sent by target to initiator when it is > ready to receive data from initiator) > 0x13 Asynchronous Message (sent by target to initiator to indicate > certain special conditions) > 0x2f Reject > > Initiator opcodes 0x38, 0x3a, 0x3c and 0x3e and target opcodes 0x39, > 0x3b, 0x3d and 0x3f are vendor specific codes. > > > > >
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