RE: iSCSI: First burst as immediate data

["Fischer, Michael" <Michael_Fischer@adaptec.com>]

 

Sastry,

 

In your case, I think that your SCSI Command PDU would carry MaxRecvPDULength worth of Data and set the F-bit to indicate that no unsolicited data PDU's follow which should instruct the target to send a R2T.  This is legal according to the third complete paragraph on page 36 of the spec which reads, "An iSCSI initiator MAY choose to send no unsolicited data, ***only immediate data*** or FirstBurstSize bytes of unsolicited data with a command. If any non-immediate unsolicited data is sent, the total unsolicited data MUST be either the negotiated amount or all the data if the total amount is less than the negotiated amount for unsolicited data."

 

Michael Fischer

-----Original Message-----
From: Subrahmanya Sastry K V [mailto:skotra@npd.hcltech.com]
Sent: Saturday, April 27, 2002 10:01 AM
To: ips@ece.cmu.edu
Subject: iSCSI: First burst as immediate data

Hi all,

I've a doubt regarding the action to be taken by the initiator given the following scenario :

Assume that the target and the initiator have agreed upon the following text parameters:

InitialR2T=Yes
ImmediateData=Yes
FirstBurstSize=64KB
MaxRecvPDULength=8KB (of the target)

The draft(11) says that if InitialR2T=Yes and ImmediateData=Yes then only immediate data are accepted in the first burst.If the FirstBurstSize is more than the MaxRecvPDULength of the target as shown above, how can the entire first burst size of data be sent as only immediate data? As per the negotiated parameters,in this case one cannot use unsolicited Data-Out PDUs to send the first burst.

Any clarifications please ?

Regards,
Sastry

-- 
Subrahmanya Sastry K V
Member Technical Staff
HCL Tech, Chennai, INDIA
http://san.hcltech.com