Re: [Printing-architecture] Google Summer of Code 2014 - IPP-over-USB printer support - Joint project idea for OpenPrinting and the kernel
Hello All,
I have a couple of "simple" follow-up questions on IPP USB (IPP-over-USB)
"Host device" support:
Is IPP USB designed to support connecting and printing from a device like a
tablet or smartphone (e.g., iPad, iPhone, Etc.) directly connected to a
printer over USB? If the answer is yes - is there any device that currently
supports this? I imagine a special cable or converter would be needed?
Or is IPP USB designed only for Hosts like Linux or Mac acting as print
servers/gateways for these, and other, devices?
Thanks,
Carlos
On Thu, Feb 27, 2014 at 11:29 AM, Michael Sweet wrote:
> Carlos,
>
> Any Mac running OS X 10.9 supports IPP USB; note that we have a bunch of
> pending bug fixes (sorry, can't say when the fixes will be released...)
> that address issues found in testing with multiple vendors' implementations
> of IPP USB, but the current 10.9.2 will work with all of the HP printers
> mentioned below.
>
>
> On Feb 27, 2014, at 2:23 PM, Carlos Rimola wrote:
>
> Michael,
>
> Thanks for the comprehensive response to my questions on IPP USB and
> confirming my assumptions.
>
> The only remaining question I have for the list at this time is - are
> there any Hosts, including model, OS and OS version (or other S/W
> requirements), presently available on the market (or otherwise) which
> support IPP USB as per the Specification?
>
> Thanks again,
>
> Carlos Rimola
>
>
> On Thu, Feb 27, 2014 at 7:37 AM, Michael Sweet wrote:
>
>> Carlos,
>>
>> On Feb 26, 2014, at 9:33 PM, Carlos Rimola wrote:
>>
>> Hi All,
>>
>> I have some quick and general questions regarding IPP over USB ("IPP USB"
>> for short). Some are related to Till's proposed project "Google Summer
>> of Code 2014 - IPP-over-USB printer support". Any help and feedback will
>> be greatly welcomed. I should mention that I am in favor of the proposed
>> project for this event.
>>
>> Assumptions (please confirm or correct):
>>
>> 1) This first one may be obvious but to be sure - I am assuming that we
>> are referring to IPP USB as defined in the "USB Print Interface Class IPP
>> Protocol Specification Revision 1.0" dated 12/5/2012 and published by
>> USB-IF and authored by HP's Smith Kennedy and Andrew R. Mitchell. I'll
>> refer to it as the "IPP USB Spec".
>>
>> Correct.
>>
>> 2) As I understand the IPP USB Spec, there is NO network interface, NOR
>> TCP/IP involved. The Communication Protocol to be used between Host and
>> Device (Printer) is *purely HTTP + IPP directly over USB*. A place where
>> this is noted is section 6.2 - "HTTP Headers" which states the following:
>>
>> *Since there is NO network interface connection, NO DNS hostnames or IP
>> addresses, and NO TCP port numbers associated with USB connection, the
>> requirements of the HTTP Host field is addressed by requiring that the
>> value of this header MUST be "localhost".*
>>
>> Please correct me if I am wrong on either of these assumptions.
>>
>>
>> Correct (a port number can be passed by the "client" over USB to allow
>> gateways/proxies to work...)
>>
>> Questions:
>>
>> 1) I know the Spec is already cast in stone but I would like to
>> understand what function HTTP serves and if it is only used for identifying
>> "Host: localhost" and the "/ipp/printer" path? In other words, could pure
>> IPP Requests/Responses and IPP expected format "Print Data" have sufficed?
>>
>> While you might get away with that for simple IPP messages, that wouldn't
>> work for document data since IPP by itself has no framing or other niceties
>> - you'd never know when the data ended.
>>
>> Also, the HTTP portion is used for the embedded web server, doing
>> firmware updates, and so forth.
>>
>>
>> 2) Section 3.2 "Interface Set" paragraph 2 states that "All IPP USBcapable
>> Print class interfaces provided by a device MUST be functionally equal
>> from an IPP operation or HTTP perspective. In other words, any IPP
>> operation or resource path that is valid over one IPP USB interface MUST
>> be reachable via any and all of the IPP USB interfaces."
>>
>> Does this imply that, for example, a Request from the host can be sent
>> over one interface (I/F #1) and the response received over a different
>> interface (e.g., I/F #2)?
>>
>> No, each interface is an independent channel to the printer.
>>
>> The reason for this requirement is to preven
Re: [Printing-architecture] Google Summer of Code 2014 - IPP-over-USB printer support - Joint project idea for OpenPrinting and the kernel
Michael,
Thanks for the comprehensive response to my questions on IPP USB and
confirming my assumptions.
The only remaining question I have for the list at this time is - are there
any Hosts, including model, OS and OS version (or other S/W requirements),
presently available on the market (or otherwise) which support IPP USB as
per the Specification?
Thanks again,
Carlos Rimola
On Thu, Feb 27, 2014 at 7:37 AM, Michael Sweet wrote:
> Carlos,
>
> On Feb 26, 2014, at 9:33 PM, Carlos Rimola wrote:
>
> Hi All,
>
> I have some quick and general questions regarding IPP over USB ("IPP USB"
> for short). Some are related to Till's proposed project "Google Summer of
> Code 2014 - IPP-over-USB printer support". Any help and feedback will be
> greatly welcomed. I should mention that I am in favor of the proposed
> project for this event.
>
> Assumptions (please confirm or correct):
>
> 1) This first one may be obvious but to be sure - I am assuming that we
> are referring to IPP USB as defined in the "USB Print Interface Class IPP
> Protocol Specification Revision 1.0" dated 12/5/2012 and published by
> USB-IF and authored by HP's Smith Kennedy and Andrew R. Mitchell. I'll
> refer to it as the "IPP USB Spec".
>
> Correct.
>
> 2) As I understand the IPP USB Spec, there is NO network interface, NOR
> TCP/IP involved. The Communication Protocol to be used between Host and
> Device (Printer) is *purely HTTP + IPP directly over USB*. A place where
> this is noted is section 6.2 - "HTTP Headers" which states the following:
>
> *Since there is NO network interface connection, NO DNS hostnames or IP
> addresses, and NO TCP port numbers associated with USB connection, the
> requirements of the HTTP Host field is addressed by requiring that the
> value of this header MUST be "localhost".*
>
> Please correct me if I am wrong on either of these assumptions.
>
>
> Correct (a port number can be passed by the "client" over USB to allow
> gateways/proxies to work...)
>
> Questions:
>
> 1) I know the Spec is already cast in stone but I would like to understand
> what function HTTP serves and if it is only used for identifying "Host:
> localhost" and the "/ipp/printer" path? In other words, could pure IPP
> Requests/Responses and IPP expected format "Print Data" have sufficed?
>
> While you might get away with that for simple IPP messages, that wouldn't
> work for document data since IPP by itself has no framing or other niceties
> - you'd never know when the data ended.
>
> Also, the HTTP portion is used for the embedded web server, doing firmware
> updates, and so forth.
>
> 2) Section 3.2 "Interface Set" paragraph 2 states that "All IPP USBcapable
> Print class interfaces provided by a device MUST be functionally equal
> from an IPP operation or HTTP perspective. In other words, any IPP
> operation or resource path that is valid over one IPP USB interface MUST
> be reachable via any and all of the IPP USB interfaces."
>
> Does this imply that, for example, a Request from the host can be sent
> over one interface (I/F #1) and the response received over a different
> interface (e.g., I/F #2)?
>
> No, each interface is an independent channel to the printer.
>
> The reason for this requirement is to prevent having an IPP USB endpoint
> just for printing, and another just for scanning, and so forth.
> Effectively IPP USB defines an interface protocol that allows arbitrary
> HTTP and IPP requests to be performed.
>
> 3) The last question is much simpler but would be helpful to an
> implementor - what specific printers (manufacturer, line and model) *on
> the market* support IPP USB? I have seen references to HP Photosmart and
> OfficeJet but no model given. Similarly, what Host(s) on the market,
> including OS and version, support the IPP USB protocol with these Printers?
>
> Here is the latest list we have from HP:
>
> Deskjet 3520
> Envy 120
> Envy 4500
> Envy 5530
> Officejet 3620
> Officejet 4630
> Officejet 7610
> Officejet Pro 276 MFP
> Officejet Pro X576 dw
> Photosmart 5520
> Photosmart 6520
> Photosmart 7520
>
> I know of four other manufacturers that either have shipping products or
> will soon be shipping - will post here when I can do so publicly...
>
> _
> Michael Sweet, Senior Printing System Engineer, PWG Chair
>
>
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Re: [Printing-architecture] Google Summer of Code 2014 - IPP-over-USB printer support - Joint project idea for OpenPrinting and the kernel
Hi All,
I have some quick and general questions regarding IPP over USB ("IPP USB"
for short). Some are related to Till's proposed project "Google Summer of
Code 2014 - IPP-over-USB printer support". Any help and feedback will be
greatly welcomed. I should mention that I am in favor of the proposed
project for this event.
Assumptions (please confirm or correct):
1) This first one may be obvious but to be sure - I am assuming that we are
referring to IPP USB as defined in the "USB Print Interface Class IPP
Protocol Specification Revision 1.0" dated 12/5/2012 and published by
USB-IF and authored by HP's Smith Kennedy and Andrew R. Mitchell. I'll
refer to it as the "IPP USB Spec".
2) As I understand the IPP USB Spec, there is NO network interface, NOR
TCP/IP involved. The Communication Protocol to be used between Host and
Device (Printer) is *purely HTTP + IPP directly over USB*. A place where
this is noted is section 6.2 - "HTTP Headers" which states the following:
*Since there is NO network interface connection, NO DNS hostnames or IP
addresses, and NO TCP port numbers associated with USB connection, the
requirements of the HTTP Host field is addressed by requiring that the
value of this header MUST be "localhost".*
Please correct me if I am wrong on either of these assumptions.
Questions:
1) I know the Spec is already cast in stone but I would like to understand
what function HTTP serves and if it is only used for identifying "Host:
localhost" and the "/ipp/printer" path? In other words, could pure IPP
Requests/Responses and IPP expected format "Print Data" have sufficed?
2) Section 3.2 "Interface Set" paragraph 2 states that "All IPP USB capable
Print class interfaces provided by a device MUST be functionally equal from
an IPP operation or HTTP perspective. In other words, any IPP operation or
resource path that is valid over one IPP USB interface MUST be
reachable viaany and
all of the IPP USB interfaces."
Does this imply that, for example, a Request from the host can be sent over
one interface (I/F #1) and the response received over a different interface
(e.g., I/F #2)?
3) The last question is much simpler but would be helpful to an implementor
- what specific printers (manufacturer, line and model) *on the
market*support IPP USB? I have seen references to HP Photosmart and
OfficeJet but
no model given. Similarly, what Host(s) on the market, including OS and
version, support the IPP USB protocol with these Printers?
Knowing this would be helpful to implement and test either device and/or
host support.
I look forward to your reply and discussing the project further.
Thanks!
Carlos Rimola
Software Developer
crim...@gmail.com
408-508-8339
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