Re: iSCSI: All text keys MUST be supported?

[julian_satran@il.ibm.com]

The current text reads:

   The data length of a text command or response SHOULD not exceed 4096
   bytes.  Key names MUST NOT exceed 63 bytes. Key values MUST NOT exceed
   255 characters.

   The reaseon for 63, 255 is to enable a separator in the 256 (64) count.

   Julo

"Eddy Quicksall" <ESQuicksall@hotmail.com> on 28-06-2001 20:43:48

Please respond to "Eddy Quicksall" <ESQuicksall@hotmail.com>

To:   "Matt Wakeley" <matt_wakeley@agilent.com>, ips@ece.cmu.edu
cc:
Subject:  Re: iSCSI: All text keys MUST be supported?




1. Without something like "MAY be selected by omission", one would think it
can't be omitted. Can you think of alternate text?
2. When I was "complaining" about the "less than 4096" below, I was not
referring to what you said ... I was referring to what the spec says ("The
data length of a text command or response SHOULD be less than 4096
bytes.").
Does anyone know why we can't go to 4096 instead of 4095 as the spec
currently says.

Eddy

----- Original Message -----
From: "Matt Wakeley" <matt_wakeley@agilent.com>
To: <ips@ece.cmu.edu>
Sent: Wednesday, June 27, 2001 12:31 PM
Subject: Re: iSCSI: All text keys MUST be supported?


> Eddy Quicksall wrote:
> >
> > 1. When I read "MAY be selected by omission", I read that if one omits
> > <key>=none, then it means the same thing as <key>=none. And that the
other
> > guy MUST adhere to that rule.
> >
> > What is your interpretation of the current text?
>
> That's the problem - it can be interpreted many different ways.
> Just delete the "MAY be selected by omission".  Make everything
explicitely
> selected.
>
> Ok, so I should have said "less than or equal to PDUlength".
> My point is, that if PDUlength is less than 4096, the message length must
not
> be larger than PDUlength.
>
> -Matt
>
> >
> > 2. Why should we limit the length to 4095 bytes when 4096 is not a
strange
> > number? Especially when we have to round things to 4 byte multiples
anyway
> > (which means 4095+one wasted byte becomes 4096). It seems we just
cheated
> > ourselves out of 1 byte.
> >
> > Eddy
> >
> > ----- Original Message -----
> > From: "Matt Wakeley" <matt_wakeley@agilent.com>
> > To: <ips@ece.cmu.edu>
> > Sent: Monday, June 25, 2001 6:00 PM
> > Subject: Re: iSCSI: All text keys MUST be supported?
> >
> > > julian_satran@il.ibm.com wrote:
> > > >
> > > > 1.2.4 reads now:
> > > >
> > > > 1.1.1     Text Mode Negotiation
> > > >
> > > >    During login and thereafter some session or connection
parameters
are
> > > >    negotiated through an exchange of textual information.
> > > >
> > > >    In "list" negotiation, the offering party sends a list of values
for
> > a
> > > >    key 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 initiator.
> > > >
> > > >    The value "none" MUST always be used to indicate a missing
function.
> > > >    However, none is a valid selection only if it is explicitly
offered
> > and
> > > >    MAY be selected by omission (i.e., <key>=none MAY be omitted).
> > >
> > > Why MAY "<key>=none" be selected by omission?  This is just another
one of
> > > those "options" that we all hate.  If it's none, explicitely say so.
> > >
> > > You also need to remove the "none MUST always be used to indicate a
> > missing
> > > function" because the following paragraph allows the use of "reject"
or
> > > "NotUnderstood" to indicate a missing function.
> > >
> > > These two paragraphs need cleaning up.
> > >
> > > >
> > > >    If a target is not supporting, or not allowed to use with a
specific
> > > >    initiator, any of the offered options, it may use the value
"reject".
> > > >    The values "none" and "reject" are reserved and must be used
only
as
> > > >    described here.  Any key not understood is answered with
> > > >    "NotUnderstood".
> > > >
> > > >    The general format of text negotiation is:
> > > >
> > > >       Offer-> <key>=<value1>,<value2>,...,<valuen>
> > > >       Answer-> <key>=<valuex>|reject|NotUnderstood
> > > >
> > > >    In "numerical" negotiations, the offering and responding party
state
> > a
> > > >    numerical value. The result of the negotiation is key dependent;
> > > >    frequently the lower or the higher of the two values is used.
> > > >
> > > >    Although the initiator is the requesting party and controls the
> > > >    request-response initiation and termination the target can offer
> > > >    key=value pairs of its own as part of a sequence and not only in
> > > >    response to an identical key=value pair offered by the
initiator.
> > > >
> > > >    And 2.8.3 reads:
> > > >
> > > > 1.1.1     Text
> > > >
> > > >    The initiator sends the target a set of key=value or key=list
pairs
> > > >    encoded in UTF-8 Unicode. The key and value are separated by a
'='
> > > >    (0x3D) delimiter. Many key=value pairs can be included in the
Text
> > block
> > > >    by separating them with null (0x00) delimiters.  A list is a set
of
> > > >    values separated by comma (0x2C). Large binary items can be
encoded
> > > >    using their hexadecimal representation (e.g., 8190 is 0x1FFE) or
> > decimal
> > > >    representation. The maximum length of an individual value (not
its
> > > >    string representation) is 255 bytes.
> > > >
> > > >    The data length of a text command or response SHOULD be less
than
> > 4096
> > > >    bytes.  Key names MUST NOT exceed 64 bytes. Key values MUST NOT
> > exceed
> > > >    255 characters.
> > >
> > > data length should be less than PDUlength.
> > >
> > > -Matt
> > >
> > >
> > >
>
>