Subject: SLP - Summary of next 'printer:' template proposal

From: Ira McDonald <[email-masked]>
Date: Wed, 13 Jan 99 20:45:16 EST

Hi folks,                                    Wednesday (13 January 1999)

This note seeks concensus before a next revision of the SLPv2 'printer:'
template.  PLEASE send your opinion to the IPP mailing list.  Also, the
SLPv2 'printer:' template will be discussed at the PWG monthly meeting
next week in Maui, Hawaii - but I won't be there - sigh...

Our concensus at today's IPP WG Telecon was:
a)  Use the SLPv2 'printer:' template as the master for writing coherent
    SLPv1-compatible concrete templates for each print protocol;
b)  REDUCE attributes in the SLPv2 'printer:' template from mandatory to
    optional, whenever reasonable;
c)  Let the IPP Model raise the conformance level for certain optional
    attributes (but only for IPP supporting printers);
d)  Specify a default value of 'unknown' or '-1' (STRING or INTEGER)
    for each optional attribute (so that an SLP User Agent can tell if
    the registration includes meaningful information, even in SLPv1);
d)  DELETE 'print-quality-supported' from the SLPv2 'printer:' template,
    because it is too subjective to be useful (unlike nominal speed);
e)  ADD a new second printer speed attribute 'pages-per-minute-color'
    (also to be added to IPP/1.0 as a registered extension).

Per my action item from today's IPP WG Telecon, here is a summary of all
attributes planned for a next revision of the SLPv2 'printer:' template,
with their SLP syntax (and flags), SLP status (mandatory or optional),
and IPP status for directory registrations (NOT for IPP Printer objects)
- per Appendix E 'Generic Directory Schema' of IPP Model and Semantics
(16 November 1998).

The next SLPv2 'printer:' template (summarized here) would have (28)
attributes, including (6) mandatory ones and (22) optional ones.  After
the summary table, a rationale is presented for EACH mandatory or
optional attribute.
        
Cheers,
- Ira McDonald (outside consultant at Xerox)
  High North Inc
  716-461-5667 (w/ voice mail)

PS - Harry Lewis posted my last update to the SLPv2 'printer:' template
today in the directory 'ftp://ftp.pwg.org/pub/pwg/ipp/new_SLP'.  Sorry I
failed to post this revised template before, except on the mailing list.

------------------------------------------------------------------------

SLP Flags
---------
L    Literal (NOT to be translated)
M    Multi-valued (comma separated in template)
O    Optional (not mandatory in template)

SLPv2 'printer:' Attribute         SLP Syntax    SLP Status  IPP Status
Name (usually IPP Name)            and Flags     (Directory) (Directory)
--------------------------         ----------    ----------- -----------
printer-uri-supported <1>          STRING L      Mandatory   Recommended
uri-security-supported <2>         STRING L      Mandatory   Recommended
printer-name <3>                   STRING        Mandatory   Recommended
printer-location (1)               STRING O      Optional    Recommended
printer-info (2)                   STRING O      Optional    Optional
printer-more-info (2)              STRING L O    Optional    Optional
printer-make-and-model (2)         STRING O      Optional    Recommended
printer-current-operator (1)       STRING O      Optional    (PrintMIB)
printer-service-person (1)         STRING O      Optional    (PrintMIB)
natural-language-configured <4>    STRING L      Mandatory   (no status)
natural-language-supported <5>     STRING L M    Mandatory   Optional
charset-configured (3)             STRING L O    Optional    (no status)
charset-supported (3)              STRING L M O  Optional    Optional
document-format-supported <6>      STRING L M    Mandatory   Recommended
color-supported (2)                STRING L O    Optional    Recommended
finishings-supported (2)           STRING L M O  Optional    Optional
number-up-supported (2)            INTEGER M O   Optional    Optional
sides-supported (2)                STRING L M O  Optional    Recommended
media-supported (2)                STRING L M O  Optional    Recommended
media-local-supported (2)          STRING M O    Optional    (see above)
printer-resolution-supported (2)   STRING L M O  Optional    Optional
[print-quality-supported] (4)      STRING L M O  Optional    Optional
copies-supported (2)               INTEGER O     Optional    (no status)
job-k-octets-supported (2)         INTEGER O     Optional    (no status)
pages-per-minute (2)               INTEGER O     Optional    (new in IPP
pages-per-minute-color (2)         INTEGER O     Optional    (new in IPP
delivery-orientation-supported (2) STRING L O    Optional    (PrintMIB)
priority-levels-supported (2)      INTEGER O     Optional    (Salutation
paper-output (2)                   STRING L M O  Optional    (Salutation

Mandatory attribute rationales
------------------------------
<1> printer-uri-supported       supports single registration object
                                - all print protocol paths (per IPP/1.0)

<2> uri-security-supported      supports direct use of each printer URI
                                - required security (per RFC 2316)

<3> printer-name                supports user-friendly access to printer
                                - natural language name (per IPP/1.0)

<4> natural-language-configured supports direct use of each printer URI
                                - configured language (per RFC 2277)

<5> natural-language-supported  supports direct use of each printer URI
                                - supported languages (per RFC 2277)

<6> document-format-supported   supports direct use of each printer URI
                                - supported PDLs (per IPP/1.0)

Optional attribute rationales
-----------------------------
(1) Often not configured by system administrators (per Hugo Parra)
(2) Often unknown to print servers (per Hugo Parra)
(3) ALL Internet application protocols MUST support UTF-8 (per RFC 2277)
(4) Propose to DELETE in next SLPv2 'printer:' template (per Hugo Parra)

---

From: Mikael Pahmp <[email-masked]>
Date: Thu, 14 Jan 1999 14:35:31 +0100

It is not mentioned in your mail if the 'printer:' template will
include conrete service schemes as before or if it should only
describe the abstract part and have separate documents for the
concrete schemes. I suggest having the conrete schemes included
for both IPP, LPR, NDPS and Raw TCP as long as they don't add too
many attributes to those that are common.

I've heard that Microsoft has a way of describing LPR printers
that discerns how different print servers implement LPR. This
information should probably be included as attributes for LPR
printers. Does anyone know what this information consists of?
I will also try to find it myself.

In a previous mail, someone noted that the Raw TCP printer
template doesn't contain a syntax description for the conrete URI.
It does. The 'url-path' is empty as it doesn't make sense to have
a path part when addressing a raw tcp port.

In the Raw TCP template, a new attribute 'device-id' is included
apart from the common ones. The data for this attribute is often
available from a paralell port printer (if it supports the IEEE
1284 standard) and can easily be included in the SLP service by a
'print server'. The Device ID is used by Windows 95/98 Plug & Play
to automatically select the correct printer driver. I suggest that
this attribute is added to the list of attributes of the abstract
printer service as an optional attribute instead as it is useful
in all print protocols when determining print driver.

/Mikael

> -----Original Message-----
> From: Ira McDonald [mailto:[email-masked]]
> Sent: den 14 januari 1999 02:45
> To: [email-masked]; [email-masked]
> Subject: SLP - Summary of next 'printer:' template proposal
> 
> 
> 
> Hi folks,                                    Wednesday (13 
> January 1999)
> 
> today in the directory 
> 'ftp://ftp.pwg.org/pub/pwg/ipp/new_SLP'.  Sorry I