[Cloud] Proposed introduction text for Cloud Print Requirements and Model

[Cloud] Proposed introduction text for Cloud Print Requirements and Model

William A Wagner wamwagner at comcast.net
Tue Mar 19 22:06:41 UTC 2013


Michael,

 

I don't want to drag this out, but I think we have a basic difference in our
understanding of the terminology.  By agreed to definition, the MFD
"supports one or more Imaging Services".  I take 'support' to mean that the
MFD contains the physical elements that execute the Service(s). It was noted
that an MFD could in fact be distributed among several pieces of equipment.
But the Semantic Model just deals with how an MFD exposes itself to an
external entity  and does not necessarily relate to  the internal structure
of the MFD. And the intent has always been to avoid dealing  with any
interfaces internal to an MFD.

 

I therefore have difficulty with the circumstance where  the "Imaging
Service does not reside on the MFD". It is my understanding that any
networked physical printer (which is an MFD) MUST  include, manifest,
implement, or contain a Print Service. (Perhaps, a very dumb printer with a
direct connection to an external computer, where the computer does Print
Service functions such as job control and rasterization, is not a MFD,
although the combination of the printer and the computer may be considered
an MFD). Of course, as in fanout, a Print Service may interface with one or
more subsequent Print Services.  Therefore, in the Cloud Printing mode, the
Cloud Print Service is interacting with a local Print Service, and it is the
assumed inability of the Cloud Print Service to initiate  connections with
the local Print Service that presents the need for defining a new set of
operations. 

 

Therefore, after indicating that the specification defines a set of actors
and their interactions  for Cloud Printing, and that the target printer may
be behind a firewall. you might want the intro to note that:

1.      The MFD Model and Common Semantics [PWG5108.01] defines the
semantics of the interface between an Imaging Service  and either a Client
or an  'upstream" Imaging Service acting as a Client, where the
communication is initiated on the Client side.

2.       In cases where Client side communication initiation is prevented,
as by a firewall, there needs to be some way by which the Imaging Service
that is the destination of the Imaging Job Request can initiate
communication with the upstream Client or Imaging Service.

3.      This specification defines an additional interface allowing a
destination  Print Service to initiate this communication.

 

I think we should also not later on that the actor we identify are
conceptual, and that the Cloud Print Manager  may very well be contained
within the MFD (Printer).

 

Thanks,

Bill Wagner

 

From: Michael Sweet [mailto:msweet at apple.com] 
Sent: Monday, March 18, 2013 2:33 PM
To: William A Wagner
Cc: cloud at pwg.org
Subject: Re: [Cloud] Proposed introduction text for Cloud Print Requirements
and Model

 

Bill,

 

On 2013-03-18, at 1:50 PM, William A Wagner <wamwagner at comcast.net> wrote:

... 

The MFD Model and Common Semantics does not define Output Device (it should)

 

Hmm, it may not define it but OutputDevice is part of the SM schema, in
PrintJobProcessingCapabilities and PrintJobProcessing.  But in any case...





...

indicate). I would suggest that Multifunction Device (MFD), which is defined
as "A hardware entity that supports one or more Imaging Services, including
the System." Be used in place of Output Device.

 

I have no objection.

 





I also question the first sentence. I suggest:,

 

The MFD Model and Common Semantics [PWG5108.01] defines the semantics of the
interface between a Client and an Imaging  Service, including one contained
in a Multifunction Device (MFD) such as a Printer. When a primary Service,
acting as a Client to the service within an MFD, has network accessibly to
the MFD, the existing Semantic Model interface applies. However, when the
MFD is not network accessible to a primary Service, a new interface is
required that allows the MFD to retrieve and update Jobs and Documents, as
well as provide current status and configuration of the MFD to the Service.

This feels awkward to me. How about:

 

The MFD Model and Common Semantics [PWG5108.01] defines the semantics of the
interface between a Client and an Imaging Service representing a
Multifunction Device (MFD) such as a Printer. When the Imaging Service does
not reside on the MFD, an additional interface between them is required.
When the MFD is network accessible to the Imaging Service, the existing
Semantic Model interface can be used with the Imaging Service acting as a
Client to the MFD's Service. However, when the MFD is not network accessible
to the Imaging Service, a new interface is required that allows the MFD to
retrieve and update Jobs and Documents, as well as provide current status
and configuration of the MFD to the Imaging Service. 

 

This specification defines a new printing interface between a Semantic Model
MFD and a Service to support situations where the MFD is not network
accessible to the Service. While the focus of this specification is on
Cloud-based Services, the same interface can be used in any situation where
the MFD is not network accessible to the Service, as is common in many
secure and multi-homed network environments. For example, a gateway Service
might use the printing interface defined by this specification to provide
guest printing from an open Wi-Fi network to a secure corporate LAN.

And a few minor changes here since this is the Cloud *Print* Requirements
and Model:

 

This specification defines a new printing interface between a Semantic Model
MFD and a Print Service to support situations where the MFD is not network
accessible to the Service. While the focus of this specification is on
Cloud-based Print Services, the same interface can be used in any situation
where the MFD is not network accessible to the Service, as is common in many
secure and multi-homed network environments. For example, a gateway Print
Service might use the printing interface defined by this specification to
provide guest printing from an open Wi-Fi network to a MFD on a secure
corporate LAN.


We can tweak the wording again when we do the multifunction version of the
spec...

 

Thanks!

 

_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair

 


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