Re: iSCSI - revised 2.2.4

[Santosh Rao <santoshr@cup.hp.com>]

Julian,

I apologize upfront for being so persistent on this. 

However, it would really help if you could give some clear example of a
scenario as to why the initiator cannot be considered the originator of
a negotiation, when it offers a key value implicitly, through the use of
a default.

Several people on this list (Paul Konning, Sanjeev, Deva, myself, and
perhaps others, that I cannot recall at the moment) have asked that the
spec must not differentiate login behaviour when the initiator offers a
key explicitly vs. when it offers a key implicitly thru the use of the
default. 

Please help us understand the need for iscsi to distingush the login
behaviour in the above case. [through some tangible scenarios and
examples]. 

Thanks,
Santosh


> "Sanjeev Bhagat (TRIPACE/Zoetermeer)" wrote:
> 
> Julian,
> 
> I would also request an explicit definition of offering party and
> responding party. The current text still leaves ambiguity when target
> sends a key in response to implicit default key of the Intiator. In
> this case who is the offering party and who is the responding party
> 
> Sanjeev
> 
>      -----Original Message-----
>      From: Julian Satran [mailto:Julian_Satran@il.ibm.com]
>      Sent: Friday, October 05, 2001 2:06 PM
>      To: ips@ece.cmu.edu
>      Subject: iSCSI - revised 2.2.4
> 
>      Here is a revised (complete) part 2.2.4 based on recent
>      agreed changes:
> 
>      1.1.1        Text Mode Negotiation
> 
>      During login and thereafter some session or connection
>      parameters are negotiated through an exchange of textual
>      information.
> 
>      All negotiations are stateless - i.e. the result MUST be
>      based only on newly exchanged values.
> 
>      The general format of text negotiation is:
> 
>      Originator-> <key>=<valuex>
>      Responder-> <key>=<valuey>|reject|NotUnderstood
> 
>      The value can be a number, a single literal constant a
>      Boolean value (yes or no) or a list of comma separated
>      literal constant values.
> 
>      In literal list negotiation, the originator sends for each
>      key a list of options (literal constants which may include
>      "none") in its order of preference.
> 
>      The responding party answers with the first value from the
>      list it supports and is allowed to use for the specific
>      originator.
> 
>      The constant "none" MUST always be used to indicate a
>      missing function. However, none is a valid selection only if
>      it is explicitly offered.
> 
>      If a target is not supporting, or not allowed to use with a
>      specific originator, any of the offered options, it may use
>      the constant "reject".  The constants "none" and "reject"
>      are reserved and must be used only as described here.  Any
>      key not understood is answered with "NotUnderstood".
> 
>      For numerical and single literal negotiations, the
>      responding party MUST respond with the required key and the
>      value it selects, based on the selection rule specific to
>      the key, becomes the negotiation result.  Selection of a
>      value not admissible under the selection rules is considered
>      a protocol error and handled accordingly.
> 
>      For Boolean negotiations (keys taking the values yes or no),
>      the responding party MUST respond with the required key and
>      the result of the negotiation when the received value does
>      not determine that result by itself.  The last value
>      transmitted becomes the negotiation result.  The rules for
>      selecting the value to respond with are expressed as Boolean
>      functions of the value received and the value that the
>      responding party would select in the absence of knowledge of
>      the received value.
> 
>      Specifically, the two cases in which responses are OPTIONAL
>      are:
> 
>      - The Boolean function is "AND" and the value "no" is
>      received. The outcome of the negotiation is "no".
>      - The Boolean function is "OR" and the value "yes" is
>      received. The outcome of the negotiation is "yes".
> 
>      Responses are REQUIRED in all other cases, and the value
>      chosen and sent by the responder becomes the outcome of the
>      negotiation.
> 
>      The value "?" with any key has the meaning of enquiry and
>      should be answered with the current value or
>      "NotUnderstood".
> 
>      The target may offer key=value pairs of its own. Target
>      requests are not limited to matching key=value pairs as
>      offered by the initiator.  However, only the initiator can
>      initiate the negotiation start (through the first Text
>      request) and completion (by setting to 1 and keeping to 1
>      the F bit in a Text request).
> 
>      Comments ?
> 
>      Julo

-- 
##################################
Santosh Rao
Software Design Engineer,
HP-UX iSCSI Driver Team,
Hewlett Packard, Cupertino.
email : santoshr@cup.hp.com
Phone : 408-447-3751
##################################