1. Internet Printing Protocol (IPP)
Scott Isaacson
Corporate Architect
Novell, Inc.
WWW7 Developer Day
April 18, 1998
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IPP - WWW7

2. Agenda Background Requirements Model Encoding HTTP Mapping Summary
Objects
Operations
Encoding
HTTP Mapping
Summary
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3. Internet Printing Protocol (IPP) Background
Fall of 1996 Printer Working Group (PWG) meeting on Internet and web printing
PWG is a loose, unincorporated alliance among printer vendors, OS vendors, and developers
IEEE 1284, Printer MIB, Job Monitoring MIB
Presentations
Lightweight Document Printing Application (LDPA)
HyperText Printing Protocol (HTPP)
Simple Web Printing (SWP)
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IPP - WWW7

4. IPP Background (cont.) PWG chartered a working group IETF
12/96: IETF BOF
3/97: IETF WG charter
4-11/97: Various Internet-Drafts
2/98: WG final call
Major Contributors
System vendors, OS vendors, device vendors, driver vendors, application vendors
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IPP - WWW7

5. Online References Mailing List: Sites: Internet-Drafts (www.ietf.org)
Sites:
AND ftp.pwg.org/pub/pwg/ipp/
Internet-Drafts (
Requirements: draft-ietf-ipp-req-02.txt
Model: draft-ietf-ipp-model-09.txt
Encoding and Transport: draft-ietf-ipp-protocol-04.txt
Rationale: draft-ietf-ipp-rat-01.txt
LPD Mapping: draft-ietf-ipp-lpd-ipp-map-01.txt
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IPP - WWW7

6. IPP WG Schedule Proposed Standard by end of April 98
Prototyping now being done
“Interoperability bake-off” 1998
Use the Internet
4 Vendors have shown interoperability
Test suites
Conference Demos
BrainShare, Xplore, Seybold, etc.
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IPP - WWW7

7. Why IPP? Evolution of network printing Multiple solutions
client attached
server attached
network attached
Multiple solutions
SPX/IPX
LPR/LPD (TCP)
Appletalk
Netbeui (SMBs)
No interoperability
High administrative overhead and complexity
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IPP - WWW7

8. IPP Mission Statement
Web tools, applications, and technologies working together to support printing on the Internet
Web browsers
URLs
MIME
HTTP
LDAP
SLP
SLP
LDAP
Directory
MIME
HTTP
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IPP - WWW7

9. Scope for IPP/1.0 End User features: Query, Submit, Cancel
Out of scope:
Driver download (URL to installation information)
Notification (current WG discussions)
Presentation and UI
Only hooks for HTML page, no standard
No Operator features
As allowed by local authorization policy
No Administrator features
Assume product specific administrative solution
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IPP - WWW7

10. Vision: Inter-Enterprise Examples
Print from an Application
Any application via IPP client pushes document data to printer
Print from a Document Repository
IPP aware application (Web Browser) pushes document data to printer
Print using a Reference
Printer pulls document data using reference
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11. Example 1: Application Printing
Enterprise A
Enterprise B
Firewall
Firewall
Internet
IPP
Printer
Application
IPP
any
Print Data
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12. Example 2: Existing File Printing
Enterprise A
Enterprise B
Firewall
Firewall
Internet
IPP
Printer
Browser
IPP
any
Print Data
Repository
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13. Example 3: Print by Reference
Enterprise A
Enterprise B
Firewall
Firewall
Internet
IPP
Printer
Browser
IPP
Print Data
any
URI Reference
Repository
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14. Architecture and Layering
Application
Spooler
Print Driver
End User
File
Browser
Notification
Directory
Naming
IPP Client
Secure Transport
IPP Server
IPP Printer
Print Service
Output Device
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15. IPP Objects
Printer
Job
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16. IPP Printer Implements IPP Logical or physical device
Multiple configurations
server
embedded
Job processing
Options for spooling and scheduling
Provide job status
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17. IPP Printer Configurations
any
IPP
Printer
IPP
any
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18. Printer Attributes (Mandatory)
Uniform Resource Identifier (URI)
Name
State
Accepting jobs
Localization
Natural Language (RFC 1766: “en-US”)
Default, Supported
Charset (RFC 2046: “utf-8”, “utf-16”)
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19. Job Attributes (Mandatory)
Job Identifier
Job Owner’s Identity
Job State
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20. Document Format Use MIME Internet Media Types
Types for traditional Page Description Languages (PDLs)
“application/postscript” (PostScript) and others (PJL/PCL, IPDS, Interpress, etc.)
Types for emerging document formats
“text/html”
“application/pdf”
Etc.
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21. Printer Operations (Mandatory)
Print-Job
Submits a Job, “pushes” job data to the Printer
Validate-Job
Validates client supplied attributes (no job data)
Get-Jobs
Lists jobs at the Printer
Get-Printer-Attributes
Responds with Printer attributes
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IPP - WWW7

22. Example: Get-Printer-Attributes
IPP
Printer
Get-Printer-Attributes Request
requested-attributes: all
Get-Printer-Attributes Response
printer-name: John’s Printer
printer-location: Bldg. A, Room 5
printer-state: processing
document-format-supported: ps, pcl
media-supported: iso-a4, na-letter
sides-supported: two-sided
queued-job-count: 45
error-code: ok
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23. Example: Get-Printer-Attributes (Printer Stopped)
IPP
Printer
Get-Printer-Attributes Request
requested-attributes:printer-description
Get-Printer-Attributes Response
printer-name: HR Color Printer
printer-state: stopped
printer-state-reasons: media-jam-error
printer-state-message: Feed Tray 1
queued-job-count:5
error-code: ok
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IPP - WWW7

24. Example: Print-Job Print-Job Request Print-Job Response
IPP
Printer
Print-Job Request
job-name: file1.doc
copies: 5
print-quality: draft
finishing: staple-top-left
job-sheet: none
data: <octet string>
Print-Job Response
job-id: 1234
job-state: pending
error-code: ok
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25. Example: Print-Job (error)
IPP
Printer
Print-Job Request
job-name: file2.doc
priority: 100
media: na-letter-transparent
finishing: punch
number-up: two
data: <octet string>
Print-Job Response
finishing: punch (unsupported)
number-up: attribute-unsupported
error-code: unsupported-attributes
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26. Job Operations (Mandatory)
Cancel-Job
End User initiated abort
Get-Job-Attributes
Responds with current attribute values
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27. Example: Cancel-Job Cancel-Job Request Cancel-Job Response
IPP
Printer
Cancel-Job Request
job-id: 1234
message: “Please discard any printed
pages.”
Cancel-Job Response
error-code: ok
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28. Multiple Document Jobs (Optional)
“Create-Job”
Creates a Job object
Validates attributes
Followed by multiple “Send-Document”
Last Document Flag
Existing practice
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29. Example: Create-Job Create-Job Request Create-Job Response
IPP
Printer
Create-Job Request
<attributes only, no data>
Create-Job Response
job-id: 5678
error-code: ok
Send-Document Request
last-document: false; document data; response: ok
last-document: true; document data; response: ok
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30. Print by Reference (Optional)
“Print-URI” operation
Client supplies attributes
Client supplies URI reference to data
Printer retrieves document data
Multiple document with references
“Send-URI”
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31. Example: Print-URI Print-URI Request Print-URI Response
IPP
Printer
Print-URI Request
job-name: Acme’s Web Page
copies: 1
document-format: text/html
document-uri:
Print-URI Response
job-id: 25
job-state: processing
error-code: ok
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32. Job Template Attributes
1) Printer supports some values
2) Printer has a default value
3) Client requests a certain value
Example: “finishings”
Printer supports: staple, cover, bind
Printer default: staple
Client requests: cover, bind
Printer Supports: a, b, d
Printer Default: b
Client Requests: a
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33. Job Template (cont.) Cover Events Priority Hold Media Number UP Sides
Copies
Resolution
Quality
Document Format (PDLs)
Compression
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34. Fidelity Printing Semantics Client supplied “fidelity” attribute
“I expect the job exactly as specified - don’t print it if you can’t do it”
“Just print the job the best you can - ignore or make substitutions as needed”
Client supplied “fidelity” attribute
boolean
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35. IPP Override of PDL Client supplies Job Template attributes
Affect rendering, production, and finishing
Conflicting instructions
Embedded PDL instructions
Example:
Request “a4” media for a job that is “letter”
Printer’s “PDL Override” attribute
Values: attempted, not-attempted
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36. Printer Attributes (Optional)
Location
More Info
HTML page
Site contact info
Description
Make and Model
Driver Installer
Color Printing Supported
PDL Override
State Reasons
Job Count
Privacy Supported
Security Supported
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37. Job Attributes (Optional)
More Info
HTML page
Language
State reasons
Output device assigned
Size
Octets, impressions
Time submitted
Time since
Pending
Processing
Completed
Number of intervening jobs
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38. Extensibility Defined mechanisms Well defined space for
Type1: Requires an update to the specification
Type2: Requires approval of the PWG
Type3: Requires IANA registration
Type4: Allows for site-by-site additions
Well defined space for
Private
Experimental
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39. Security Does not reinvent the wheel Look to HTTP Look to Transport
basic, digest, and beyond
Look to Transport
Transport Layer Security (TLS)
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40. Encoding and Transport
Encoding: application/ipp
Simple, regular, binary
Embedded solutions
“application/ipp”
Proposal: XML for protocol data
Transport: HTTP/1.1
Ubiquitous (HTTP/1.0 still possible although not optimal)
Leverage features (URI naming, chunking, etc.)
Printing has already embraced HTTP servers (administration)
Focus on simplicity (complexity relates to proxy servers)
Security
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41. Transport Mapping Use HTTP/1.1 Each IPP operation is an HTTP POST
“Request URI” is the IPP object
“Content Type” is “application/ipp”
Authentication/authorization checks
Leverage HTTP negotiation:
Cache and proxy control
Proposal: Add new PRINT operations to HTTP
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IPP - WWW7

42. Encoding Diagram: “application/ipp”
POST HTTP/1.1
Content-Type: application/ipp
VERSION
2 bytes - required
REQUEST ID
2 bytes - required
OPERATION / STATUS CODE
2 bytes - required
ATTRIBUTE TAG
1 byte
0 or more
ATTRIBUTE SEQUENCE
n bytes
DATA TAG
1 byte - required
DATA
m bytes
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43. Conclusion
IPP is close to ratification as a set of IETF Proposed Standard RFCs
Several interoperable prototypes
Ongoing discussions for new features and standard extensions
All are invited to participate
“application/ipp” operations over HTTP
Flexible, Scalable
Diverse implementations
Diverse configurations
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IPP - WWW7