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    Re: iSCSI Draft 11 Comments and MaxCmdSN rule




    Hasebe-San,

    I am looking at the text and I am sorry - I am using Framemaker and the paragraph you quoted as appearing twice
    does not appear on my text.

    I looked again at the published chapter 2 - and some how the whole chapter contains both the INSERTED and DELETED text from versions 10 and 11 (evidence on page 33 chapter7 and chapter 8).

    I will correct the pdf at my site.

    As for the second comment - I will fix it in the next text.

    Thanks for catching this.
    Julo




    y-hasebe@ah.jp.nec.com
    Sent by: owner-ips@ece.cmu.edu

    06-03-02 08:12
    Please respond to y-hasebe

           
            To:        ips@ece.cmu.edu
            cc:        
            Subject:        iSCSI Draft 11 Comments and MaxCmdSN rule

           



    Julian & All,

    I have two comments on the draft 11 file.
    (http://www.haifa.il.ibm.com/satran/ips/draft-ietf-ips-iscsi-11.pdf)

    (1) Editional Comment
     On page 31, This sentence appers twice in this page.
     (Line 3 and Line 20)
     
      "The target MUST NOT transmit a MaxCmdSN that is less than the last
      ExpCmdSN. For non-immediate commands, the CmdSN field can take any
      value from ExpCmdSN to MaxCmdSN. The target MUST silently ignore any
      non-immediate command outside of this range or non-immediate duplicates
      within the range."

    (2)MaxCmdSN rule
     I think that this sentence should change as Ayman says.
     This sentence is a confusing expression.

     On Page 31, Line 3
      "The target MUST NOT transmit a MaxCmdSN that is less than the last
      ExpCmdSN. "

                            change to

      "The target MUST NOT transmit a MaxCmdSN that is less than the last
      ExpCmdSN-1. "


    -------------------
    Yoshihiro Hasebe
    NEC Corporation
    -------------------

    -------------------- Attached Mail -------------------------------

    Please consider also carefully the Serial Arithmetic rules with regard to
    "lower/higher" and the bounds on the ExpComdSN and MaxCmdSN difference.

    Julo
    ----- Forwarded by Julian Satran/Haifa/IBM on 08-02-02 02:26 -----
                                                                                               
                       "Ayman Ghanem"                                                          
                       <aghanem@cisco       To:     <ips@ece.cmu.edu>                          
                       .com>                cc:                                                
                       Sent by:             Subject:     RE: iSCSI: MaxCmdSN rule              
                       owner-ips@ece.                                                          
                       cmu.edu                                                                  
                                                                                               
                                                                                               
                       08-02-02 00:53                                                          
                                                                                               
                                                                                               



    This sentence should be changed to:

    "The target MUST NOT transmit a MaxCmdSN that is less than the last
    ExpCmdSN-1"

    The paragraph above this states:

    "If the PDU MaxCmdSN is less than the PDU ExpCmdSN-1 (in Serial Arithmetic
    Sense), they are both ignored."

    which allows MaxCmdSN = ExpCmdSN-1,valid, for the case when the target's
    command window is closed.

    -Ayman

    -----Original Message-----
    From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
    Buck Landry
    Sent: Thursday, February 07, 2002 2:40 PM
    To: ips@ece.cmu.edu
    Subject: iSCSI: MaxCmdSN rule

     Hi all, I'm struggling over how to interpret this rule in section 1.2.2 of
    draft v10:

    >>> The target MUST NOT transmit a MaxCmdSN that is less than
            the last ExpCmdSN.
    <<<

    This confuses me because it says to me (in some cases) that a target must
    be able to handle an unlimited number of commands.  For example, let's say
    the target has just about reached the limit of the commands it can handle:

    T=>(Nop-In) (MaxCmdSN = 1, ExpCmdSN = 1)

    I=>(Scsi Read Cmd) (CmdSN = 1)

    T=>(Data-in) (MaxCmdSN = 1, ExpCmdSN = 2 /* acknowledging scsi read cmd
    */)

    Now the target may have many more data-ins to transmit.  But according to
    the rule, since the last ExpCmdSN the target transmitted was 2, the target
    is now forced to send a MaxCmdSN of 2:

    T=>(Data-in) (MaxCmdSN = 2, ExpCmdSN = 2)

    But this allows the initiator to send another command, even though the
    target can't handle it!

    Obviously something is wrong with my reasoning here (perhaps my
    interpretation of 'last ExpCmdSN', or when I"m supposed to acknowledge the
    scsi cmd); can anybody clarify?

    --buck




    ----- Forwarded by Julian Satran/Haifa/IBM on 08-02-02 02:26 -----
                                                                                               
                       "Buck Landry"                                                            
                       <blandry@cross       To:     <ips@ece.cmu.edu>                          
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                       Sent by:             Subject:     iSCSI: MaxCmdSN rule                  
                       owner-ips@ece.                                                          
                       cmu.edu                                                                  
                                                                                               
                                                                                               
                       07-02-02 22:40                                                          
                                                                                               
                                                                                               



    Hi all, I'm struggling over how to interpret this rule in section 1.2.2 of
    draft v10:

    >>> The target MUST NOT transmit a MaxCmdSN that is less than
           the last ExpCmdSN.
    <<<

    This confuses me because it says to me (in some cases) that a target must
    be able to handle an unlimited number of commands.  For example, let's say
    the target has just about reached the limit of the commands it can handle:

    T=>(Nop-In) (MaxCmdSN = 1, ExpCmdSN = 1)

    I=>(Scsi Read Cmd) (CmdSN = 1)

    T=>(Data-in) (MaxCmdSN = 1, ExpCmdSN = 2 /* acknowledging scsi read cmd */)

    Now the target may have many more data-ins to transmit.  But according to
    the rule, since the last ExpCmdSN the target transmitted was 2, the target
    is now forced to send a MaxCmdSN of 2:

    T=>(Data-in) (MaxCmdSN = 2, ExpCmdSN = 2)

    But this allows the initiator to send another command, even though the
    target can't handle it!

    Obviously something is wrong with my reasoning here (perhaps my
    interpretation of 'last ExpCmdSN', or when I"m supposed to acknowledge the
    scsi cmd); can anybody clarify?

    --buck





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