Carl-Uno Manros opened the meeting and reviewed the agenda.
Steve Zilles then briefly provided a quick overview of IPP,
specifically the object concept. Steve then handed the meeting
off to Scott Isaacson for review of current Model document
issues and proposed resolutions.
The specific issues and resolutions included:
1. BEST-EFFORT
This attribute has been changed to "ipp-attribute-fidelity"
2. document-name
"document-name" is optional - the printer will assign some
document-name to a document if not specified by the client.
3. Persistence of ignored attributes
If values are ignored or substituted by an IPP server, the
originally requested attributes that were replaced will not
be queryable by a client (queryable?)
4. "Job Problems" in notifications
Clarified the "job problems" specification in the "notify-events"
attribute description. The "job problems" specification reflects
the state of the job at the moment in time when the notify occurs.
5. "Printer Problems"
Similar to "job problems", this value reflects the current state
of the "printer-state-reasons" value.
6. Compression of IPP messages
This issue is OPEN. The WG is looking at other standards and
existing enumerations for compression algorithms.
7. Alignment with Job MIB
job-k-octets, job-impressions, and job-media-objects will be
aligned semantically with the job MIB.
One note about the job MIB. Keith Moore, our area director for
applications, noted that there is no formal IETF working group
chartered for the Job MIB effort. Further, there may be problems
with IPP achieving "proposed" status if IPP documents reference
such other documents. He reiterated that the Printer Working
Group had submitted an extension to the Printer MIB working
group's charter to include the Job MIB, but that the request
was rejected by the IESG, so there may be a problem here.
8. MANDATORY job attributes
All "time-since-xxxx" attributes are OPTIONAL.
"number-of-intervening-jobs" is also OPTIONAL.
"job-name" is MANDATORY. Must be assigned by client or printer.
"job-originating-user" and "job-originating-host" are being
merged into a single "job-originating-ID". This new attribute
is MANDATORY, and is required to enable IPP security.
9. Human Language and Character Set
IPP mandates UTF-8 for application/ipp messages. HTTP Accept-Headers
will be used for human-language attributes. Questions from the
audience asked about whether the WG had considered the use of
an updated Unicode spec. UCS-4 which is currently being proposed.
Scott Isaacson implied that the WG is open to suggestions as to
what standard should be applied here. The basic theme echoed by
Keith Moore was to try and follow Harald Alvestrand's document, and
if better methods are suggested, the IESG will keep an open mind.
10. Job "Processing" state
Scott Isaacson explained why the "processing" state was defined,
instead of a "printing" state. Basically, "Logical" and "Physical"
printers are supported within the IPP model, and the "processing"
state is less confusing when the job is actually being worked
on by a "logical" printer. If the model was restricted to purely
"physical" printers, then "printing" might have sufficed.
11. Job-State-Reasons
Remove references to log files
12. number-of-intervening-jobs
Will be OPTIONAL - remains in document.
13. Job-URI attribute
"A lively discussion ensued". Basically, it was agreed that
this issue is still OPEN and will be discussed on the mailing
list.
14. Use of "Conditionally Mandatory" in IPP documents.
The I-D will be re-edited to focus on what must be implemented
in order to realize certain specific functional components.
Keith Moore reflected on current IETF documents for keywords
such as MUST, SHOULD, MAY, etc. and that the WG should try and
follow the IETF guidelines and best current practice with
regards to such conformance/compliance vocabulary.
15. MANDATORY job attributes
Again, clarification of the current I-D with regards to
MANDATORY and OPTIONAL is needed. Also, default attribute
bindings are applied "late", at job processing time, and not
job submission time.
16. Use of MIME types for "document-format"
Currently, the model document specifies the use of Printer MIB
enumerations for specification of document-format. In addition,
at a recent IPP meeting, it was agreed that enumerations for
PDF and HTML would be added to this list.
Upon hearing the proposed alignment with the Printer MIB for
these values, "a lively discussion ensued".
It was the opinion of Larry Masinter (chair of HTTP WG), Keith
Moore, and most of the IETF audience that alignment with the
Printer MIB was a mistake, and that we should focus on sticking
with MIME-type specifications.
Further, Keith Moore went on to say that the current draft of
the Printer MIB was "broken", and that he is seriously
considering delaying advancement of the Printer MIB draft until
this (and possibly other) issues are addressed. Keith did not
go into any detailed analysis of why the MIB was broken, but
seemed to suggest that there were more than one reason why it's
broken. He went on to say that its possible that (ironically)
the IESG might suggest to the working group that the Printer
MIB should align itself with the MIME-types and change the way
that interpreters are enumerated in the MIB. He suggested that
the group should consider strings, and not enumerations, to
specify these types (i.e., MIME types). Keith was pretty adamant
on this issue and would have conntinued discussion, but Steve Z.
and Scott suggested that discussion on the Printer MIB was
not appropriate at an IPP WG meeting.
17. Use of "well known values" in IPP documents.
Basically, the specification of a value as "well-known" will
be removed.
18. Status Code Mappings
The specification of status code mappings is inconsistent. The
mapping between status codes and IPP operations will be reviewed.
19. Server Timeout
The printer will abort a job after some server-configured
inactivity timeout. If some documents had already been printed,
the rest of the job is cancelled. Larry Masinter questioned
why IPP operations could not be "re-tried" if a failure occurred.
Steve Zilles responded that there might be idempotency problems
with operation retries. More discussion on the mailing list
should be done.
20. Extensibility of attributes & syntaxes
These extensions should be accomplished via type-2 enumerations.
21. Version Numbers
Given the number of HTTP WG members in the room, "a lively
discussion on capability negotiation and version numbers
ensued. It is very likely that some combination of versioning,
and capability negotiation will be required before gaining
IESG acceptance.
22. Directory syntax/schema
More work needs to be done to bring the current directory schema
documents up to date with the current Model document. One of
the members of the Service Location Protocol WG mentioned that
they already have started working on a schema for Printing Class
applications within their WG, and that input from the IPP WG
is "very welcome" at this stage. Scott Isaacson stated that
such cooperation should definitely teke place.
23. User Name
See job-originating-id. This attribute will replace the user-name
attribute.
24. Color
Will remain a boolean, "color-supported'. Leave it to the PDL
to handle other color model and capabilities requirements.
Some questions by the audience questioned the usefulness of a
"boolean" to specify color capabilities. Keith Moore said that
he would like to see the specification of color capabilities
more fleshed out than just "yes, this device supports color".
Larry Masinter also suggested that in order to curb the
displeasure with such a "boolean" specification of color, that
maybe the WG should remove this and just do a complete color
capabilities model in a future version of IPP. He suggested that
either IPP should do color (the right way), or not at all.
After a brief rationale statement by Scott Isaacson and Steve
Zilles for the boolean color-supported, both Larry and Keith
seemed to understand why, but still were not crazy about the
inclusion of color, without the WG "doing it right".
25. "document-char-set"
Describes the coded character set of the PDL data - the WG
agreed to add it.
26. Filter for Get-Jobs operation
The WG deemed this capability too complex for IPP 1.0
27. Date and Time
"time-since-xxxx" attributes will be in "seconds" (and OPTIONAL).
A MANDATORY "printer-up-time" will be added to the spec. and
will essentially reflect the MIB-II "sysUpTime" object. Larry
Masinter questioned why a printer "end-user" would care about
how long the printer had been "up", since IPP 1.0 is basically
targeted for end-users. He further questioned why the value
was mandatory. The WG implied that since MIB-II sysUpTime was
mandatory, that no undue burden should be placed on IPP
implementations to support it.
28. Account-Name
The specification of an account-name has been POSTPONED.
29. Should Validate-Job be OPTIONAL?
The WG decided that it should be MANDATORY.
30. Formatting Attributes
The WG will work on a proposal for "page-range" and
"page-orientation" attributes.
31. Attribute Group Names
Support of IPP attribute group names is MANDATORY, however
one or more attributes within these groups may be OPTIONAL.
32. Order of Jobs returned by "Get-Jobs"
OPEN.
33. Support for NCs (Network Computers)
Unclear. This topic was pushed to a future version of IPP WG
to decide.
34. Event Notification
The WG has an action item to specify event notifications. They
should be machine-readable.
35. media-ready vs. media-supported
OPEN. Some implementation require this distinction. Especially
server-based implementations of IPP. It was suggested that
media-supported be dropped and only support for media-ready
should be supported, since this would apply to all IPP
configurations.
36. Collated vs. Uncollated copies
Add two other ranges of values, one for "collated" and one for
"uncollated" copies.
37. Printer-State-Reasons
Action item to align with Printer MIB generic alerts.
38. Printer Name
No restrictions should be placed on printer names. This should
be a "site policy".