I claim that IPP/1.1 already allows a Printer to return the OOB value
'unknown' for any supported attribute. So, it would automatically be
allowed for "redirection-printers-supported". The semantics of 'unknown'
might actually make sense here. The Printer is saying that it doesn't know
which Printers it can redirect to; it can only try them on a case-by-case
basis. So a client, on seeing 'unknown', might decide to go ahead and try
redirecting to some Printer it has in mind. Worst comes to worst, the
request will be rejected.
Or we could use 'any'.
The heart of the issue is in the containment matching rules. The spec says
things like "if the client-supplied xxx is not contained in the Printer's
xxx-supported, the Printer MUST reject the request". Presumably, if
xxx-supported is 'any', it matches any client-supplied xxx. If
xxx-supported is 'unknown', that might be interpreted as saying that the
Printer will decide whether or not to reject a supplied xxx only when it
has seen the request.
"Hastings, Tom N" <email@example.com> on 07/18/2000 01:50:01 PM
To: Carl Kugler/Boulder/IBM@IBMUS, Michael Sweet <firstname.lastname@example.org>
cc: "Hastings, Tom N" <email@example.com>, firstname.lastname@example.org
Subject: RE: IPP> OPS - Redirect-Job (a ka Move-Job) included in Job and P
rinter Admin (Set2) spec
We considered your request to either add 'any' as a new out-of-band value,
or to extend the existing 'unknown' out-of-band (OOB) value to mean any.
The group agreed to add 'any', since it requires an updated client to not
confused querying the Printer before sending the job, if the client queries
the Printer as to what it supports before sending the job. (On the other
hand, an existing client that is simply querying the Printer will become
confused by a new OOB value).
You only requested it for "document-format-supported" (for use by a Printer
object that represents a Document Repository, instead of an output device).
However, in this example you are suggesting that the OOB value could also
used as the value of the "redirection-printers-supported" (1setOf uri)
Printer attribute, correct?
From: email@example.com [mailto:firstname.lastname@example.org]
Sent: Tuesday, July 18, 2000 09:32
To: Michael Sweet
Cc: Hastings, Tom N; email@example.com
Subject: Re: IPP> OPS - Redirect-Job (a ka Move-Job) included in Job and
Printer Admin (Set2) spec
The Printer could return the OOB 'unknown' value in
"redirection-printers-supported" and let the client attempt a Redirect-Job
to any printer-uri. The operation will either succeed or return an error
Michael Sweet <firstname.lastname@example.org> on 07/17/2000 07:06:14 PM
> It's an implementation detail whether or not the
> "redirection-printers-supported" are on the same server. You only
> need to specify the protocol. If an implementation can meet the
> spec, it doesn't matter how it does it. You don't need to specify
But this brings up the issue of how we specify "all" servers,
i.e. we don't want to enumerate every printer-uri on the planet,
do we? :)
-- ______________________________________________________________________ Michael Sweet, Easy Software Products email@example.com Printing Software for UNIX http://www.easysw.com
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