[MFD] RE: [IPP] Attributes needed for Cloud Printing and definition inconsistencies [4 questions about the representation of the values]

[MFD] RE: [IPP] Attributes needed for Cloud Printing and definition inconsistencies [4 questions about the representation of the values]

[MFD] RE: [IPP] Attributes needed for Cloud Printing and definition inconsistencies [4 questions about the representation of the values]

Zehler, Peter Peter.Zehler at xerox.com
Mon Jul 26 17:06:27 UTC 2010


Before the wiki write-up by Mike is simply accepted as the IPP Everywhere definition, I want to be sure we have complete agreement on the exact semantics and syntax for the PWG as a whole.  I assume a single definition of semantics and abstract syntax is preferred.  Once we have consensus I will add that to the PWG Semantic model.  Individual protocol binding specifications can handle the encoding of the attributes.  If the PWG definition differs from RFC1876, I want to be sure that differences and mapping is clearly explained. After reading Mike's definition and RFC1876 it seems to me that they are not the same.


Peter Zehler

Xerox Research Center Webster
Email: Peter.Zehler at Xerox.com
Voice: (585) 265-8755
FAX: (585) 265-7441
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 128-25E
Webster NY, 14580-9701 

-----Original Message-----
From: Ira McDonald [mailto:blueroofmusic at gmail.com] 
Sent: Monday, July 26, 2010 12:55 PM
To: Zehler, Peter; Ira McDonald
Cc: tom.hastings at alum.mit.edu; ipp at pwg.org; mfd at pwg.org; cloud at pwg.org
Subject: Re: [MFD] RE: [IPP] Attributes needed for Cloud Printing and definition inconsistencies [4 questions about the representation of the values]

Hi,

The "printer-geo-location" attributes on that Wiki were
written by Mike Sweet and intended *specifically* for
the IPP Everywhere project.

They can certainly be added to PWG SM XML Schema
and used for Cloud Printing, but *in IPP specs* they'll be
documented in the single IPP Everywhere Protocol spec
(*after* we complete the IPP Everywhere Requirements
spec mandated by our project charter).

Cheers,
- Ira

Ira McDonald (Musician / Software Architect)
Chair - Linux Foundation Open Printing WG
Co-Chair - TCG Hardcopy WG
IETF Designated Expert - IPP & Printer MIB
Blue Roof Music/High North Inc
http://sites.google.com/site/blueroofmusic
http://sites.google.com/site/highnorthinc
mailto:blueroofmusic at gmail.com
winter:
  579 Park Place  Saline, MI  48176
  734-944-0094
summer:
  PO Box 221  Grand Marais, MI 49839
  906-494-2434



On Mon, Jul 26, 2010 at 7:52 AM, Zehler, Peter <Peter.Zehler at xerox.com> wrote:
> My comments are  inline below
>
>
>
>
>
> Peter Zehler
>
> Xerox Research Center Webster
> Email: Peter.Zehler at Xerox.com
> Voice: (585) 265-8755
> FAX: (585) 265-7441
> US Mail: Peter Zehler
> Xerox Corp.
> 800 Phillips Rd.
> M/S 128-25E
> Webster NY, 14580-9701
>
>
>
> From: Tom Hastings [mailto:tom.hastings at verizon.net]
> Sent: Monday, July 26, 2010 1:11 AM
> To: Zehler, Peter; ipp at pwg.org; mfd at pwg.org; cloud at pwg.org
> Subject: RE: [IPP] Attributes needed for Cloud Printing and definition
> inconsistencies [4 questions about the representation of the values]
>
>
>
> Pete,
>
>
>
> I have 4 questions about your proposed IPP attributes for Geo Location for
> Cloud Printing:
>
>
>
> 1. The representation of the values of your proposed IPP "size",
> "horizontal-precision", and "vertical-precision" attributes are completely
> different from the representation of the same attributes in RFC1876.
>
> <PZ>I made a mistake in my values.  I used 8 bit unsigned integers instead
> of 4 bit.  The values should be; Size= 18 (0x12), HorizontalPrecision=34
> (0x22), VerticalPrecision=34 (0x22).  (This is why I really don't like this
> representation.  That and the fact that for the dimensions associated with
> MFDs it is not as precise a expressing it in simple centimeters)</PZ>
>
>
>
> If this difference is intentional, it would be good to explain the
> difference and why and to indicate this intended difference in the spec?
>
>
>
> As I read RFC 1876, the representation of the SIZE, HORIZ PRE, and VERT PRE
> attributes are all using this funny SIZE representation as a pair of
> four-bit unsigned integers, where the most significant 4-bit unsigned
> integer represents the base and the second 4-bit integer represents the
> power of 10 by which to multiple the base, sort of a compressed floating
> point representation, but using power of 10, not power of 2.  The reason
> give in RFC 1876 is so that the value is more easily human readable.  HORIZ
> PRE and VERT PRE attributes defined in RFC 1876, say:
>
>
>
> expressed using the same representation as SIZE
>
> i.e., using this same 8-bit "floating point" representation.
>
>
>
> BTW, the VERT PRE attribute has an ironic Freudian slip typo in RFC 1876,
> since I don't find this representation very sane L:
>
> expressed using the sane representation as for SIZE
>
>
>
>
>
> 2. The definitions on the <http://pwg-wiki.wikispaces.com/Geolocation>
> appear to be part of the PWG Semantic Model:
>
>
>
> This page proposes an IPP collection representing the DNS LOC data defined
> in RFC 1876 .
> printer-geo-location (collection)
> The "printer-geo-location" attribute provides the physical location of the
> printer. The collection has the following member attributes.
> size (integer (0:MAX))
>
> Diameter of enclosing sphere for printer in centimeters. 0 represents any
> size less than one centimeter.
> horizontal-precision (integer (0:MAX))
>
> The circle of error of the latitude and longitude measurement in
> centimeters. 0 represents an error of less than one centimeter.
> vertical-precision (integer(0:MAX))
>
> The circle of error of the altitude measurement in centimeters. 0 represents
> an error of less than one centimeter.
> latitude (integer(-324000000:324000000))
>
> The latitude in thousandths of arc seconds from the equator. 0 represents
> the equator, positive values represent locations North of the equator, and
> negative values represent locations South of the equator.
> longitude (integer(-648000000:648000000))
>
> The longitude in thousandths of arc seconds from the prime meridian. 0
> represents the prime meridian, positive values represent locations East of
> the meridian, and negative values represent locations West of the meridian.
> altitude (integer(-100000:MAX))
>
> The distance in centimeters from the WGS-84 ellipsoid to the center of the
> enclosing sphere defined by the "side" member attribute. 0 represents the
> WGS-84 ellipsoid height, positive values represent locations above the
> ellipsoid, and negative values represent locations below the ellipsoid.
>
>
>
> The PWG SM definitions appear to use signed 32-bit integer notation and
> description which have the same bit representation as the unsigned 32-bit
> integer notation and description in RFC 1876, right?  Why change to use the
> unsigned integer notation and descriptions, when the rest of the SM and IPP
> use signed integer notations and descriptions?
>
> <PZ>To the best of my knowledge printer-geo-location  is not part of the PWG
> semantic model yet.  I put out this mail note to test my understanding of
> the proposal on the wiki site.  I want to be sure the semantics and syntax
> are well defined and the mapping to rfc1876 is clear.</PZ>
>
>
>
>
>
> 3. What is the relationship between Cloud Printing (which these definitions
> are proposed for) and IPP Everywhere?
>
> <PZ>Cloud Printing can be implemented without IPP Everywhere.  The initial
> implementations will not be using IPP or IPP Everywhere.  It will be cobbled
> together with existing technologies used in Web Services, messaging
> protocols, standard document formats and print driver related technologies.
> IPP could play a role in this environment but I believe it is most critical
> to obtain semantic alignment between IPP and the emerging Cloud Printing
> technologies.  IPP Everywhere addresses a number of IPP shortcomings such as
> printer discovery, common document formats, and interoperable security.  IPP
> Everywhere could apply to Cloud Printing but would require some extensions
> to accommodate intervening firewalls.</PZ>
>
>
>
>
>
> 4. I like the idea used in IPP and the SM to have the data type indicate the
> range of values in the definition of the attribute name and attribute
> syntax, i.e., latitude (integer(-324000000:324000000)).  Why isn't this
> technique of specifying the data type and the data type range used in your
> proposal for attributes needed for Cloud Printing?
>
> <PZ>Added to definitions below.</PZ>
>
>
>
> Tom
>
> ________________________________
>
> From: ipp-bounces at pwg.org [mailto:ipp-bounces at pwg.org] On Behalf Of Zehler,
> Peter
> Sent: Thursday, July 22, 2010 11:48
> To: ipp at pwg.org; mfd at pwg.org
> Subject: [IPP] Attributes needed for Cloud Printing and definition
> inconsistencies
>
>
>
> Job Identifiers:
>
> *existing*
>
> job-id (SM: JobId): The identifier for a job with a local scope.  That is
> the ID is unique within the service.  The ID may be reused in other instance
> of a Printer (i.e. Print Service)  or for jobs in other types of services
> (e.g. Copy Service).  Datatype: abstract:int32, IPP:integer, SM:xs:int
>
>
>
> *new*
>
> job-uuid (SM:JobUuid):  The identifier for a job with a global scope.  The
> identifier is unique for a Job across all service instances of any service
> type.    The UUID URN namespace is specified in rfc4122.  The format used
> for "job-uuid" is the string representation of a UUID as a URN.  An example
> is "urn:uuid:a6b90f34-d0b1-1956 -7dec-009c4386fe3".  The version (aka
> subtype) used is implementation specific.  Version 1 (i.e. time based) is
> recommended.   Datatype: abstract:char[64], IPP:uri MaxLength=64,
> SM:xs:anyURI maxLen=64
>
>
>
> Note:  I do not believe the IPP attribute "job-uri" is applicable as a
> globally unique identifier.
>
> 1)      RFC2911 states "Since every URL is a specialized form of a URI, even
> though the more generic term URI is used throughout the rest of this
> document, its usage is intended to cover the more specific notion of URL as
> well.".   All uses of the uri syntax is really a URL syntax.
>
> 2)      URL implies not only a specific protocol binding but also a
> location.
>
> 3)      Locations can be specified using an IP address that need not be
> locally unique (e.g. 192.168.1.1, localhost)
>
> 4)      Regarding the "job-uri" RFC2911  further states that "This URI is
> then used by clients as the target for subsequent Job operations.".  The
> globally unique identifier for a job should not specify a transport endpoint
> for a specific protocol.
>
> 5)      The globally unique identifier for a Job, Printer or Service should
> be a URN.  It should be protocol independent so that a product that supports
> multiple protocols should have the same identifiers regardless of the
> protocol mapping.
>
> 6)      The  globally unique identifier for a Job, Printer or Service should
> require no central authority to administrate them.  Generation of a unique
> identifier should be simple from an administrative point of view and
> preferably automated.
>
>
>
> Note: Both the local and global identifiers should be mandated.  For legacy
> protocol mappings (e.g. IPP 1.1, WS-Print, LPR) the local identifier MUST
> still be maintained.  It is possible to use the time_low portion of the
> Timestamp in the version 1 UUID as the local identifier.  The implementation
> may then keep only the 128 bit local representation of the UUID and use it
> to create the appropriate protocol values.
>
>
>
> Printer Identifiers:
>
> *existing (Service Monitoring MIB)*
>
> applIndex (SM: <service>Id i.e. PrinterId): The service identifier with a
> local scope.  That is the ID is unique across the service instances
> collocated on a host.  Datatype: abstract:int32, MIB:integer, SM:xs:int
>
>
>
> *new*
>
> printer-uuid (SM:ServiceUuid):  The identifier for a Printer with a global
> scope.  The identifier is unique across all service instances of any service
> type.    The UUID URN namespace is specified in rfc4122.  The format used
> for "job-uuid" is the string representation of a UUID as a URN.  An example
> is "urn:uuid:a6b90f34-d0b1-1956 -7dec-009c4386fe3".  The version (aka
> subtype) used is implementation specific.  Version 1 (i.e. time based) is
> recommended.   Datatype: abstract:char[64], IPP:uri, SM:xs:anyURI maxLen=64
>
>
>
> Note:  I do not believe the IPP attribute "printer-uri" is applicable as a
> globally unique identifier.
>
> 1)      RFC2911 states "Since every URL is a specialized form of a URI, even
> though the more generic term URI is used throughout the rest of this
> document, its usage is intended to cover the more specific notion of URL as
> well.".   All uses of the uri syntax is really a URL syntax.
>
> 2)      URL implies not only a specific protocol binding but also a
> location.
>
> 3)      Locations can be specified using an IP address that need not be
> locally unique (e.g. 192.168.1.1, localhost)
>
> 4)      The printer may have multiple "printer-uri" values as enumerated in
> the "printer-uris-supported" attribute.  There should be only a single
>  identifier for a printer.
>
> 5)      The globally unique identifier for a Job, Printer or Service should
> be a URN.  It should be protocol independent so that a product that supports
> multiple protocols should have the same identifiers regardless of the
> protocol mapping.
>
> 6)      The  globally unique identifier for a Job, Printer or Service should
> require no central authority to administrate them.  Generation of a unique
> identifier should be simple from an administrative point of view and
> preferably automated.
>
>
>
>
>
> Note: The local instance id in the MIB and SM are artifacts of the model's
> data binding and are insufficient for use as an identifier.  IPP's
> printer-uri, the URL for Web Service bindings (e.g. WS-Print) and the IP
> address for legacy protocols such as LPR and Port 9100 are also
> insufficient.  They need not be globally unique.  Nonroutable IP addresses
> may be used.
>
>
>
> Printer Location:
>
> *existing*
>
> printer-location (SM: ServiceLocation): Identifies the location of the
> device that this Printer represents.  (Example: Pete's Office)  This is
> helpful for a human but is pretty much useless for geolocation since the
> content is implementation specific.   Datatype: abstract:char[127],
> IPP:string MaxLength=127, SM:xs:int
>
>
>
> *new*
>
> printer-geo-location (SM:ServiceGeoLocation):  This identifies the location
> of the associated device using the World Geodetic System 1984(WGS84).  The
> means for expressing the location information is the same as used in DNS
> (rfc1876)  Datatype: abstract:class, IPP:collection, SM:sequence
>
>
>
> *new*(modified)
>
> size (SM:Size) (0x00 to 0x99):  Diameter of the bounding sphere containing
> the device expressed in centimeters.    Datatype: abstract: int32,
> IPP:integer, SM:xs:int  (Note: representation is 2 encoded 4 bit
> integers(0-9).  Most significant represents the base and the least
> significant represents the power of 10.)
>
>
>
> *new*(modified)
>
> horizontal-precision (SM: HorizontalPrecision) (0x00 to 0x99):  The
> horizontal precision expressed as the diameter of the "circle of error"
> (i.e. twice the +- error value)  The units are centimeters.    Datatype:
> abstract: int32, IPP:integer, SM:xs:int(Note: representation is 2 encoded 4
> bit integers(0-9).  Most significant represents the base and the least
> significant represents the power of 10.)
>
>
>
> *new*(modified)
>
> vertical-precision (SM: VerticalPrecision) (0x00 to 0x99):  The vertical
> precision expressed as the diameter of the "circle of error" (i.e. twice the
> +- error value)  The units are centimeters.    Datatype: abstract:integer,
> IPP: int32, SM:xs:int(Note: representation is 2 encoded 4 bit
> integers(0-9).  Most significant represents the base and the least
> significant represents the power of 10.)
>
>
>
> *new* (modified)
>
> latitude (SM:Latitude(1823483648 to 4618967296): ):  The latitude of the
> center of the sphere described by the size attribute.  Expressed in
> thousandths of a second of arc.  The value 2147483648  (231) represents the
> equator.  Values above that are north and below are south.   Datatype:
> abstract: int32, IPP:integer, SM:xs:int
>
>
>
> *new* (corrected) (modified)
>
> longitude (SM:Latitude) (1499483648  to 4942967296) The longitude of the
> center of the sphere described by the size attribute.  Expressed in
> thousandths of a second of arc.  The value 2147483648  (231) represents the
> prime meridian.  Values above that are east and below are west.  The value
> is rounded away from the prime meridian   Datatype: abstract: int32,
> IPP:integer, SM:xs:int
>
>
>
> *new* (modified)
>
> altitude (SM:Altitude) (0 to MAX):  The altitude of the center of the sphere
> described by the size attribute.  Expressed in centimeters from a base of
> 100,000m below the reference spheroid used by GPS [WGS 84].  Altitude above
> (or below) sea level may be used as an approximation of altitude relative to
> the [WGS 84] spheroid, though due to the Earth's surface not being a perfect
> spheroid, there will be differences.    Datatype: abstract: int32,
> IPP:integer, SM:xs:int
>
>
>
> Note:  There is disagreement on the semantics for all the attributes between
> what is posted on <http://pwg-wiki.wikispaces.com/Geolocation>  and what I
> have in the definition above.  I took the definition directly from rfc1876
> (I think).  See included text from rfc1876 and the location example below.
>
>
>
>
>
>
>
> Peter Zehler
>
> Xerox Research Center Webster
> Email: Peter.Zehler at Xerox.com
> Voice: (585) 265-8755
> FAX: (585) 265-7441
> US Mail: Peter Zehler
> Xerox Corp.
> 800 Phillips Rd.
> M/S 128-25E
> Webster NY, 14580-9701
>
>
>
>
>
> From rfc1876 section 2 <http://www.rfc-editor.org/rfc/rfc1876.txt>
>
>
>
> SIZE         The diameter of a sphere enclosing the described entity, in
>
>              centimeters, expressed as a pair of four-bit unsigned
>
>              integers, each ranging from zero to nine, with the most
>
>              significant four bits representing the base and the second
>
>              number representing the power of ten by which to multiply
>
>              the base.  This allows sizes from 0e0 (<1cm) to 9e9
>
>              (90,000km) to be expressed.  This representation was chosen
>
>              such that the hexadecimal representation can be read by
>
>              eye; 0x15 = 1e5.  Four-bit values greater than 9 are
>
>              undefined, as are values with a base of zero and a non-zero
>
>              exponent.
>
>
>
>              Since 20000000m (represented by the value 0x29) is greater
>
>              than the equatorial diameter of the WGS 84 ellipsoid
>
>              (12756274m), it is therefore suitable for use as a
>
>              "worldwide" size.
>
>
>
> HORIZ PRE    The horizontal precision of the data, in centimeters,
>
>              expressed using the same representation as SIZE.  This is
>
>              the diameter of the horizontal "circle of error", rather
>
>              than a "plus or minus" value.  (This was chosen to match
>
>              the interpretation of SIZE; to get a "plus or minus" value,
>
>              divide by 2.)
>
>
>
> VERT PRE     The vertical precision of the data, in centimeters,
>
>              expressed using the sane representation as for SIZE.  This
>
>              is the total potential vertical error, rather than a "plus
>
>              or minus" value.  (This was chosen to match the
>
>              interpretation of SIZE; to get a "plus or minus" value,
>
>              divide by 2.)  Note that if altitude above or below sea
>
>              level is used as an approximation for altitude relative to
>
>              the [WGS 84] ellipsoid, the precision value should be
>
>              adjusted.
>
>
>
> LATITUDE     The latitude of the center of the sphere described by the
>
>              SIZE field, expressed as a 32-bit integer, most significant
>
>              octet first (network standard byte order), in thousandths
>
>              of a second of arc.  2^31 represents the equator; numbers
>
>              above that are north latitude.
>
>
>
> LONGITUDE    The longitude of the center of the sphere described by the
>
>              SIZE field, expressed as a 32-bit integer, most significant
>
>              octet first (network standard byte order), in thousandths
>
>              of a second of arc, rounded away from the prime meridian.
>
>              2^31 represents the prime meridian; numbers above that are
>
>              east longitude.
>
>
>
> ALTITUDE     The altitude of the center of the sphere described by the
>
>              SIZE field, expressed as a 32-bit integer, most significant
>
>              octet first (network standard byte order), in centimeters,
>
>              from a base of 100,000m below the [WGS 84] reference
>
>              spheroid used by GPS (semimajor axis a=6378137.0,
>
>              reciprocal flattening rf=298.257223563).  Altitude above
>
>              (or below) sea level may be used as an approximation of
>
>              altitude relative to the the [WGS 84] spheroid, though due
>
>              to the Earth's surface not being a perfect spheroid, there
>
>              will be differences.  (For example, the geoid (which sea
>
>              level approximates) for the continental US ranges from 10
>
>              meters to 50 meters below the [WGS 84] spheroid.
>
>              Adjustments to ALTITUDE and/or VERT PRE will be necessary
>
>              in most cases.  The Defense Mapping Agency publishes geoid
>
>              height values relative to the [WGS 84] ellipsoid.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> 2-Dimmensional Location of my office printer
>
> Google Map URL:
>
> http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=800+phillips+rd+webster+ny+14580&sll=37.0625,-95.677068&sspn=62.226996,106.962891&ie=UTF8&hq=&hnear=800+Phillips+Rd,+Webster,+Monroe,+New+York+14580&ll=43.220973,-77.417162&spn=0.001781,0.003264&t=h&z=19
>
> Location representations:
>
> Decimal Degrees (WGS84)
>
> Latitude Longitude
> 43.220973 -77.417162
>
> Degrees, Minutes & Seconds
>
> Latitude Longitude
> N43 13 15 W77 25 01
>
> GPS
>
> Latitude Longitude
> N 43 13.258 W 77 25.030
>
> UTM
>
>  X Y
>
> 18N 303685 4788191
>
>
>
> My office elevation:
>
> 12800 centimeters (419 feet) above sea level
>
> Size of Printer:
>
> 91 centimeter (3 feet)
>
> Margin of error
>
> 183 centimeter (6 feet)
>
>
>
> PrinterGeoLocation (RFC1876) (Corrected)
>
> Size = 18 (0x12) (encoded centimeter) (corrected)
> HorizontalPrecision = 34 (0x22)  (encoded centimeter) (corrected)
> VerticalPrecision = 34 (0x22)  (encoded centimeter) (corrected)
>
> Latitude = 2303079151 (thousandths of a second of arc, 231 represent
> equater)  ( (DecimalDegreeLatitude*60*60*1000)+2147483648 )
>
> Longitude = 1868781865 (thousandths of a second of arc, 231 represent prime
> meridian) ( 2147483648-(DecimalDegreeLongitude*60*60*1000) )
> Altitude = 10012800 (centimeter)  (OfficeElevation+10000000)
>
>
>
>
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
> _______________________________________________
> mfd mailing list
> mfd at pwg.org
> https://www.pwg.org/mailman/listinfo/mfd
>
>

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.




More information about the mfd mailing list