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    iSCSI: draft04 questions



    Julian,
    
    Thanks for incorporating a lot of the earlier reflector feedback 
    into the latest draft.
    
    Some questions:
    
    1. Section 1.2.5 states :
    	"Unsolicited data MUST be sent on every connection in the 
    	same order in which commands were sent. If the amount of data 
    	exceeds the amount allowed for unsolicited write data, the 
    	specific connection MUST be stalled - i.e., no more unsolicited 
    	data will be sent on this connection until the specific command 
    	has finished sending all its data and has received a response."
    
    Sorry if there was a discussion on this already.  Why not the iSCSI 
    response of "Unsolicited data rejected" usable for this case?  Initiator
    appears to be behaving erratically, and I don't see how it is expected
    to adhere to the stipulation that it shall not send anymore unsolicited
    data till this command is completed.
    
    2. I didn't find a way for an iSCSI target to say that it does not support 
    any unsolicited data at all.  SPC-2 specifies that a zero FirstBurstSize
    means unlimited.
    
    3. Section 2.14 states: 
    	"If an initiator intends to start recovery for a failing connection it
       	MUST use the either the Logout command to "clean-up" the target end
       	of a failing connection and enable recovery to start, or use the
       	restart option of the Login command to the same effect."
    This seems to be contradicting section 2.10.1, where a prior logout of the
    CID is stated as a requirement for using the restart bit of the Login PDU
    (which I agree with).
    
    
    4. Somehow, "Asynchronous Message" seems at odds with the rest of the
    usage in the draft in regards to PDUs (since a message is introduced as
    PDU in section 1.2).  Should we may be just call it an AEN PDU?  Section
    2.14.3 calls this so.  (I realize that it may not always result in a 
    SCSI-level AER.)
    
    5. In the same section 2.18, I dont' quite see the operational difference
    for an initiator, if any, between iSCSI event codes 2 & 3.  Could you please
    comment?  
    
    Also, isn't the time in seconds the maximum time than the minimum
    time as currently stated? 
    
    6. In section 2.20.1, reject reason code 5 is stated as a "command 
    restart reject".  Seems like the usage of "restart" in the draft elsewhere
    is for the connection/session login, and "retry" is for commands -
    except this one.  Comment if I am reading too much into the usage.
    
    7. Section 6.2 on digest errors states:
    	"If the error is a Data-Digest-Error in a Data-PDU, the target 
    	MUST either request retransmission with a R2T or answer with 
    	a Reject iSCSI PDU and abort the task."
    Were you meaning the target's internal termination of the task? That
    could cause problems on a subsequent Data PDU reception from the 
    initiator since there may be no state for the task in the target.  
    Suggest dropping "and abort the task".
    
    8. Same section states the following:  
    	"When an initiator receives an iSCSI data PDU with a Data-Digest
       	error, it must discard the PDU and it MUST either request the missing
       	data PDUs through SACK or terminate the command with an error."
    If you meant reporting a service failure to SCSI within the initiator, 
    seems like that could cause trouble to initiator iSCSI layer since it 
    is likely to receive the data/status PDUs for the command shortly thereafter.
    Suggest dropping "or terminate the command with an error", or replace
    with "or abort the task".
    
    9. End of section 6.7.1 states:
    	"An iSCSI target MAY reject a data-SACK and terminate the command with
       	an iSCSI error response of SACK rejected."
    
    The "SACK rejected" iSCSI response code needs to be added in section 2.4.2.
    
    Thanks.
    --
    Mallikarjun 
    
    
    Mallikarjun Chadalapaka
    Networked Storage Architecture
    Network Storage Solutions Organization
    MS 5668	Hewlett-Packard, Roseville.
    cbm@rose.hp.com
    


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Last updated: Tue Sep 04 01:05:28 2001
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