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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI : New PDU opcode usage in rev 5.92Santosh, Is it not the case that requests go in the direction from the Initiator to Target, where Target is the one "listening" for new connections on the well-known port? A dual mode scsi implementation therefore has two separate sessions and sets of connections. One set is [I->DualModeTarget] and the other is [DualModeInitiator->T] and the connections are independent. If I and T happens to be the same system, you can not use a single connection for bidirectional sessions between the two. So if you receive a PDU from a target, you can only do so with SourcePort set to well-known-port, and it must be a Response from target. May be I'm assuming something that is not valid... Venkat Rangan Rhapsody Networks Inc. http://www.rhapsodynetworks.com -----Original Message----- From: Santosh Rao [mailto:santoshr@cup.hp.com] Sent: Wednesday, April 18, 2001 6:47 PM To: ips@ece.cmu.edu Subject: iSCSI : New PDU opcode usage in rev 5.92 Julian & All, I've got a quick question on how the new opcode layouts would work for dual mode scsi implementations. (i.e. initiators that responded in target mode or targets that acted as initiators also). The new opcode layout is : ---------------- X|I| | | | | | | ---------------- 7 6 5 4 3 2 1 0 where bits 5-0 -> opcode X -> retry bit I -> immediate bit The same values are used for the command as well as response opcodes and bits X & I are intended to both be set to 1 by targets. i.e. opcode for scsi command = scsi response = 0x01. the distinction b/n command and response is based on targets setting X & I bits to 1. Now, if an initiator [capable of target mode] sent the following commands, how would they be interpreted : 1) 0xc4. is this a text command being retried in immediate mode, or is it a text response ? 2) 0xc1 is this a scsi command being retried in immediate mode, or is it a scsi response ? 3) 0xc2 is this a scsi task mgmt command being retried in immediate mode, or is it a scsi task mgmt response ? etc..... - Santosh -- ################################# Santosh Rao Software Design Engineer, HP, Cupertino. email : santoshr@cup.hp.com Phone : 408-447-3751 #################################
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