Re: Reg: Bidirectional command format ?
Paul von Behren <[email protected]>
| Newsgroups | gmane.ietf.ips |
|---|---|
| Message-ID | <[email protected]> |
Eddy Quicksall wrote: > Is anyone aware of any bidi SCSI commands? Look at the OSD command set (on the T10 site). I think all the OSD commands are bidi. I think that's the only command set now with bidi commands. Paul > > Eddy > > ----- Original Message ----- From: "William Studenmund" > <[email protected]> > To: "Praveen Madhavan" <[email protected]> > Cc: <[email protected]> > Sent: Friday, June 16, 2006 3:04 PM > Subject: Re: [Ips] Reg: Bidirectional command format ? > > >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> >> On Jun 16, 2006, at 5:37 AM, Praveen Madhavan wrote: >> >>> Hi Folks, >>> >>> Can any one point me the frame format of bidirectional command in >>> case of iSCSI & FCP ?.. I was trying to route bidirectional command >>> recv'd from iSCSI initiator to FC Target.. >>> >>> Here is the iSCSI PDU format for bi-direct command recv from initiator >>> ---------------------------------------------------------------------- >>> -------------------------- >>> | BHS >>> (48bytes) >>> | >>> | R & W bit set to >>> ONE, | >>> | Expected xfer len = >>> 0x200 | >>> | Total AHS Length = 2 >>> (8bytes) | >>> | SCSI CDB = Write(10) Transfer length = 00 01 ( 512 bytes) | >>> >>> ---------------------------------------------------------------------- >>> --------------------------| >>> | AHS ( 8 >>> bytes) >>> | >>> | Expected Read data length = 0x200(512 >>> bytes) | >>> ---------------------------------------------------------------------- >>> ---------------------------- >>> >>> Here is the FCP format for bi-direct command that i frame for >>> sending it to target. >>> >>> ---------------------------------------------------------------------- >>> -------------------------- >>> | FC-Header >>> (24bytes) | >>> |--------------------------------------------------------------------- >>> --------------------------- >>> | FCP-Header(36 >>> bytes) | >>> | R & W bit set to >>> ONE, | >>> | Additional CDB length = >>> 0 | >>> | SCSI CDB = Write(10) Transfer length = 00 01 ( 512 >>> bytes) | >>> | FCP_DL = 0x200 ( 512 >>> bytes) | >>> | FCP_BIDIRECTIONAL_READ_DL = 0x200(512) | >>> >>> ---------------------------------------------------------------------- >>> ---------------------------| >>> >>> Well, I am not quite sure about the CDB values in case Bidir >>> commands.. >>> Will Bi directional cmds use Write CDB(10) or Read CDB (10) ? .. >> >> >> No. Read and Write in normal sizes (6, 10, 12, 16) are unidirectional. >> >> Each specific command has either no data phase (test unit ready), >> has at most a data-out phase (Write for instance), at most a >> data-in phase (Read), or is bidirectional. >> >>> How can i control following bidi- operation in case of iSCSI & FCP ? >>> 1.bidirectional command with read before write operation >>> 2.bidirectional command with write before read operation >> >> >> You really don't need to do anything different for BiDi commands, >> other than be able to keep both a Write and a Read residual. As you >> note, the SCSI Command Request will indicate what data phases the >> initiator expects, you need only map them along. >> >> How does the target announce/control data flow in FCP? You need only >> pass that information on to the iSCSI layer. If the FCP target sends >> you data, then you send the initiator a bunch of Data-In PDUs. >> However it is that FCP controls data openings translates into R2Ts >> to the iSCSI initiator. >> >> Take care, >> >> Bill >> -----BEGIN PGP SIGNATURE----- >> Version: GnuPG v1.4.1 (Darwin) >> >> iD8DBQFEkwDZDJT2Egh26K0RAjqYAJ4yfTh+dkihI/Ha0RGhZN5NJ22zUQCfRc1L >> 7fPzAAxZZUa3mX6JsaEMPYs= >> =a55F >> -----END PGP SIGNATURE----- >> >> _______________________________________________ >> Ips mailing list >> [email protected] >> https://www1.ietf.org/mailman/listinfo/ips >> > > _______________________________________________ > Ips mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/ips _______________________________________________ Ips mailing list [email protected] https://www1.ietf.org/mailman/listinfo/ips