RFC1759 - Printer MIB

Network Working Group R. Smith
Request for Comments: 1759 Texas Instruments
Category: Standards Track F. Wright
Lexmark International
T. Hastings
Xerox Corporation
S. Zilles
Adobe Systems, Inc.
J. Gyllenskog
Hewlett-Packard Company
March 1995
Printer MIB
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Table of Contents
1. IntrodUCtion ................................................ 3
1.1 Network Printing Environment ............................... 3
1.2 Printer Device Overview .................................... 4
1.3 Categories of Printer Information .......................... 5
1.3.1 Descriptions ............................................. 5
1.3.2 Status ................................................... 5
1.3.3 Alerts ................................................... 5
2. Printer Model ............................................... 6
2.1 Overview of the Printer Model .............................. 8
2.2 Printer Sub-Units .......................................... 8
2.2.1 General Printer .......................................... 8
2.2.2 Inputs ................................................... 9
2.2.3 Media .................................................... 9
2.2.4 Outputs .................................................. 9
2.2.5 Finishers ................................................ 10
2.2.6 Markers .................................................. 10
2.2.7 Media Paths .............................................. 11
2.2.8 System Controller ........................................ 11
2.2.9 Interfaces ............................................... 11
2.2.10 Channels ................................................ 12
2.2.11 Interpreters ............................................ 12
2.2.12 Console ................................................. 12
2.2.13 Alerts .................................................. 13
2.2.13.1 Status and Alerts ..................................... 13
2.2.13.2 Overall Printer Status ................................ 13
2.2.13.2.1 Host MIB Printer Status ............................. 15
2.2.13.2.2 Sub-unit Status ..................................... 17
2.2.13.3 Alert Tables .......................................... 18
2.2.13.4 Alert Table Management ................................ 19
2.3 Read-Write Objects ......................................... 20
2.4 Enumerations ............................................... 22
2.4.1 Registering Additional Enumerated Values ................. 22
3. Objects from other MIB Specifications ....................... 22
3.1 System Group objects ....................................... 22
3.2 System Controller .......................................... 23
3.3 Interface Group objects .................................... 23
4. Textual Conventions ......................................... 23
5. The General Printer Group ................................... 27
5.1 The Cover Table ............................................ 30
5.2 The Localization Table ..................................... 31
5.3 The System Resources Tables ................................ 33
6. The Responsible Party group ................................. 35
7. The Input Group ............................................. 35
8. The Extended Input Group .................................... 41
9. The Input Media Group ....................................... 42
10. The Output Group ........................................... 44
11. The Extended Output Group .................................. 48
12. The Output Dimensions Group ................................ 49
13. The Output Features Group .................................. 51
14. The Marker Group ........................................... 52
15. The Marker Supplies Group .................................. 58
16. The Marker Colorant Group .................................. 62
17. The Media Path Group ....................................... 64
18. The Channel Group .......................................... 68
18.1 The Channel Table and its underlying structure ............ 69
18.2 The Channel Table ......................................... 70
19. The Interpreter Group ...................................... 73
20. The Console Group .......................................... 81
20.1 The Display Buffer Table .................................. 82
20.2 The Console Light Table ................................... 83
21. The Alerts Group ........................................... 85
21.1 The Alert Time Group ...................................... 92
22. Appendix A - Glossary of Terms ............................. 98
23. Appendix B - Media Size Names .............................. 101
24. Appendix C - Media Names ................................... 103
25. Appendix D - Roles of Users ................................ 107
26. Appendix E - Participants .................................. 111
27. Security Considerations .................................... 113
28. Authors" Addresses ......................................... 113
1. Introduction
1.1. Network Printing Environment
The management of producing a printed document, in any computer
environment, is a complex subject. Basically, the task can be divided
into two overlapping pieces, the management of printing and the
management of the printer. Printing encompasses the entire process of
producing a printed document from generation of the file to be
printed, selection of a printer, choosing printing properties,
routing, queuing, resource management, scheduling, and final printing
including notifying the user. Most of the printing process is outside
the scope of the model presented here; only the management of the
printer is covered.
Figure 1 - One Printer"s View of the Network
system printer asset user user user
manager operator manager
O O O O O O
/ / / / / /
/ / / / / /

+---------+ +-------+ +-------+ +-------+ +-----------+ +-----------+
configur- printer asset printer user user
ator manager manager browser application application
+---------+ +-------+ +-------+ +-------+ +-----------+ +-----------+
^ ^ ^ ^
R/W R/W R R +-----------+ +-----------+
spooler spooler
+-----------+ +-----------+

+-----------+ +-----------+
supervisor supervisor
+-----------+ +-----------+
^ ^ ^ ^
R R/W R R/W
v v
================================================== =====
print print
SNMP data data
+-----+ +-------+ PCL PCL
MIB <------> agent PostScript PostScript
+-----+ +-------+ NPAP NPAP
unspecified etc. etc.
+=============+ +-----------------+
--channel/interface<--+
+-----------------+
PRINTER
+-----------------+
--channel/interface<----------------+
+=============+ +-----------------+
1.2. Printer Device Overview
A printer is the physical device that takes media from an input
source, produces marks on that media according to some page
description or page control language and puts the result in some
output destination, possibly with finishing applied. Printers are
complex devices that consume supplies, produce waste and have
mechanical problems. In the management of the physical printing
device the description, status and alert information concerning the
printer and its various subparts has to be made available to the
management application so that it can be reported to the end user,
key operators for the replenishment of supplies or the repair or
maintenance of the device. The information needed in the management
of the physical printer and the management of a printing job overlap
highly and many of the tasks in each management area require the same
or similar information.
1.3. Categories of Printer Information
Information about printers is classified into three basic categories,
descriptions, status and alerts.
1.3.1. Descriptions
Descriptions convey information about the configuration and
capabilities of the printer and its various sub-units. This
information is largely static information and does not generally
change during the operation of the system but may change as the
printer is repaired, reconfigured or upgraded. The descriptions are
one part of the visible state of the printer where state means the
condition of being of the printer at any point in time.
1.3.2. Status
Status is the information regarding the current operating state of
the printer and its various sub-units. Status is the rest of the
visible state of the printer. As an example of the use of status, a
management application must be able to determine if the various sub-
units are ready to print or are in some state that prevents printing
or may prevent printing in the future.
1.3.3. Alerts
An Alert is the representation of a reportable event in the printer.
An event is a change in the state of the printer. Some of those state
changes are of interest to a management application and are therefore
reportable. Typically, these are the events that affect the printer"s
ability to print. Alerts usually occur asynchronously to the
operation of the computer system(s) to which the printer is attached.
For convenience below, "alert" will be used for both the event caused
by a change in the printer"s state and for the representation of that
event.
Alerts can be classified into two basic categories, critical and
non-critical. A critical alert is one that is triggered by entry
into a state in which the printer is stopped and printing can not
continue until the condition that caused critical alert is
eliminated. "Out of paper", "toner empty" and "output bin full" are
examples of critical alerts. Non-critical alerts are triggered by
those events that enter a state in which printing is not stopped.
Such a non-critical state may, at some future time, lead to a state
in which printing may be stopped. Examples of this kind of non-
critical alerts are "input media low", "toner low" and "output bin
nearly full". Or, a non-critical alert may simply provide
information, such as signaling a configuration changed in the
printer.
Description, status and alert information about printer can be
thought of as a data base describing the printer. The management
application for a printer will want to view the printer data base
differently depending on how and for what purposes the information in
the data base is needed.
2. Printer Model
In order to accomplish the management of the printer, an abstract
model of the printer is needed to represent the sub-units from which
the printer is composed. A printer can be described as consisting of
13 types of sub-units. It is important to note that the sub-units of
a printer do not necessarily relate directly to any physically
identifiable mechanism. Sub-units can also be a set of definable
logical processes, such as interpreters for page description
languages or command processors that set various operating modes of
the printer.
Figure 2 shows a block diagram of the printer and its basic 13 sub-
units.
Figure 2 - Printer Block Diagram
Physical Connections

+-----------+

+-------------+
Interface -+
(RFC1213)
+-------------+

+-----------+

+-------------+ +-----------+
Channel -+ Operator
Console
+-------------+ +-----------+

+-----------+ +---------+

+-----------+ +-------------+ +-----------+
General Interpreter -+ Alerts -+
Printer
+-----------+ +-------------+ +-----------+

+-------------------------------+
System Controller
(This is the Host MIB)
+-------------------------------+
+------+ +--------+ +--------+

+-------+ +-------+ +---------+ +-------+ +--------+
Input -+ +--------+ Marker -+ +--------+ Output -+
===> +<==> <==> +==>
+-------+ +--+ +--+ +---------+ +--+ +--+ +--------+



+--------+ +------------------------- +---------+
+--------------------------+
+----------+ Media Path + +----------+
Media -+ +--------------------------------+ Finisher -+
(optional) (optional)
+----------+ +----------+
2.1. Overview of the Printer Model
The model has three basic parts: (1) the flow of a print file into an
interpreter and onto the marker, (2) the flow of media through the
marker and (3) the auxiliary sub-units that control and facilitate
the two prior flows. The flow of the print data comes through a
physical connection on which some form of transport protocol stack is
running. The data provided by the transport protocol (interface)
appears on a channel which is the input to an interpreter. The
interpreter converts the print data into a form suitable for marking
on the media.
The media resides in Input sub-units from which the media is selected
and then transported via a Media Path first to a Marking sub-unit and
then onto an Output sub-unit with (optionally) some finishing
operations being performed. The auxiliary sub-units facilitate
control of the printer, inquiry/control of the operator panel,
reporting of alerts, and the adaptation of the printer to various
natural languages and characters sets. All the software sub-units run
on the System Controller which represents the processor, memory and
storage systems of the Printer. Each of the sub-units is discussed
in more detail below.
All of the sub-units other than the Alerts report only state
information, either a description or a status. The Alerts sub-unit
reports event information.
2.2. Printer Sub-Units
A printer is composed of 13 types of sub-units, called groups. The
following sections describe the different types of sub-units.
2.2.1. General Printer
The general printer sub-unit is responsible for the overall control
and status of the printer. There is exactly one general printer sub-
unit in a printer. The general printer sub-unit is represented by the
General Printer Group in the model. In addition to the providing the
status of the whole printer and allowing the printer to be reset,
this Group provides information on the status of the packaging of the
printer, in particular, the covers. The general printer sub-unit is
usually implemented on the system controller.
The localization portion of the general printer sub-unit is
responsible for identifying the natural language, country, and
character set in which character strings are eXPressed. There may be
one or more localizations supported per printer. The available
localizations are represented by the Localization table.
Localization is only performed on those strings in the MIB that are
explicitely marked as being localized. All other character strings
are returned in ASCII.
The character set portion of the general printer sub-unit is
responsible for identifying the possible character sets that are used
by the interpreters, the operator console, and in network management
requests for display objects. There may be one or more character sets
per printer. The understood character sets are represented by the
Character Set Table.
2.2.2. Inputs
Input sub-units are mechanisms that feed media to be marked on into
the printer. A printer contains one or more input sub-units. These
are represented by the Input Group in the model. The model does not
distinguish fixed input bins from removable trays, except to report
when a removable tray has been removed.
There are as many input sub-units as there are distinctly selectable
input "addresses". For example, if a tray has an option for manually
feeding paper as well as automatically feeding from the tray, then
this is two input sub-units if these two sources can be (must be)
separately selected and is one input sub-unit if putting a sheet in
the manual feed slot overrides feeding from the contents of the tray;
that is, in the second case there is no way to separately select or
address the manual feed slot.
2.2.3. Media
An input sub-unit can hold one or more instances of the media on
which marking is to be done. Typically, there is a large set of
possible media that can be associated with an input. The Media Group
is an extension of the Input Group which represents that media that
is in an input sub-unit. The Media Group only describes the current
contents of each input and not the possible content of the input
sub-unit.
2.2.4. Outputs
Output sub-units are mechanisms that receive media that has been
marked on. A printer contains one or more output mechanisms. These
are represented by the Output Group in the model. The model does not
distinguish fixed output bins from removable output bins, except to
report when a removable bin has been removed.
There are as many output sub-units as there are distinctly selectable
output "addresses". Output sub-units can be addressed in two
different ways: (1) as a set of "mailboxes" which are addressed by a
specific mailbox selector such as a bin number or a bin name, or (2)
as a set of "slots" into which multiple copies are collated.
Sometimes both modes of using the output sub-units can be used on the
same printer. All that is important from the viewpoint of the model
is that the output units can be separately selected.
2.2.5. Finishers
A finisher is a sub-unit that performs some operations on the media
other than marking. The finisher sub-units are represented by the
Finisher Group in the model. Some examples of finishing processes
are stapling, punching, binding, inserting, or folding. Finishing
processes may have supplies asssociated with the process. Stapling,
binding, and punching are examples of processes that have supplies. A
printer may have more than one finishing sub-unit and each finishing
sub-unit may be associated with one or more output sub-units.
Finishers are not described in this MIB.
The exact interaction and sequencing between an output device and its
associated finisher is not specified by the model. It depends on the
type of finishing process and the exact implementation of the printer
system. This standard allows for the logical association of a
finishing process with an output device but does not put any
restrictions on the exact sequence or interaction with the associated
output device. The output and finisher sub-units may or may not be
separate identifiable physical mechanisms depending on the exact
implementation of a printer. In addition, a single output device may
be associated with multiple finishing sub-units and a single
finishing sub-unit may be associated with multiple output devices.
2.2.6. Markers
A marker is the mechanism that produces marks on the print media. The
marker sub-units and their associated supplies are represented by the
Marker Group in the model. A printer can contain one or more marking
mechanisms. Some examples of multiple marker sub-units are: a
printer with separate markers for normal and magnetic ink or an
imagesetter that can output to both a proofing device and final film.
Each marking device can have its own set of characteristics
associated with it, such as marking technology and resolution.
In this model the marker sub-unit is viewed as very generalized and
encompasses all ASPects of a marking process. For example, in a
xero-graphic process, the marking process as well as the fusing
process would be included in the generalized concept of the marker.
With the generalized concept of a marking process, the concept of
multiple marking supplies associated with a single marking sub-unit
results. For example, in the xerographic process, there is not only a
supply of toner, but there can also be other supplies such as a fuser
supply that can be consumed and replaced separately. In addition
there can be multiple supplies of toner for a single marker device,
as in a color process.
2.2.7. Media Paths
The media paths encompass the mechanisms in the printer that move the
media through the printer and connect all other media related sub-
units: inputs, outputs, markers and finishers. A printer contains one
or more media paths. These are represented by the Media Path Group in
the model. The Media Path group has some objects that apply to all
paths plus a table of the separate media paths.
In general, the design of the media paths determines the maximum
speed of the printer as well as the maximum media size that the
printer can handle. Media paths are complex mechanisms and can
contain many different identifiable sub-mechanisms such as media
movement devices, media buffers, duplexing units and interlocks. Not
all of the various sub-mechanisms reside on every media path. For
example, one media path may provide printing only on one surface of
the media (a simplex path) and another media path may have a sub-
mechanism that turns the media over and feeds it a second time
through the marker sub-unit (a duplex path). The duplex path may
even have a buffer sub-mechanism that allows multiple copies of the
obverse side to be held before the reverse side of all the copies are
marked.
2.2.8. System Controller
The System Controller is the sub-unit upon which the software
components of the Printer run. The System Controller is represented
in the model by the Host MIB. This MIB allows for the specification
of the processor(s), memory, disk storage, file system and other
underlying sub-mechanisms of the printer. The controller can range
from simple single processor systems to multiprocessor systems. In
addition, controllers can have a full range of resources such as hard
disks. The printer is modeled to have one system controller even
though it may have more than one processor and multiple other
resources associated with it.
2.2.9. Interfaces
An interface is the communications port and associated protocols that
are responsible for the transport of data to the printer. A printer
has one or more interface sub-units. The interfaces are represented
by the Interfaces Group of MIB-II (RFC1213). Some examples of
interfaces are serial ports (with little or no protocol) and EtherNet
ports on which one might run InterNet IP, Novell IPX, etc.
2.2.10. Channels
The channel sub-units identify the independent sources of print data
(here print data is the information that is used to construct printed
pages and may have both data and control aspects). A printer may
have one or more channels. The channel sub-units are represented by
the Channel Group in the Model. Each channel is typically identified
by the electronic path and service protocol used to deliver print
data to the printer. A channel sub-unit may be independently enabled
(allowing print data to flow) or disabled (stopping the flow of print
data). It has a current Control Language which can be used to specify
which interpreter is to be used for the print data and to query and
change environment variables used by the interpreters (and SNMP).
There is also a default interpreter that is to be used if an
interpreter is not explicitly specified using the Control Language.
Channel sub-units are based on an underlying interface.
2.2.11. Interpreters
The interpreter sub-units are responsible for the conversion of a
description of intended print instances into images that are to be
marked on the media. A printer may have one or more interpreters. The
interpreter sub-units are represented by the Interpreter Group in the
Model. Each interpreter is generally implemented with software
running on the System Controller sub-unit. The Interpreter Table has
one entry per interpreter where the interpreters include both Page
Description Language (PDL) Interpreters and Control Language
Interpreters.
2.2.12. Console
Many printers have a console on the printer, the operator console,
that is used to display and modify the state of the printer. The
console can be as simple as a few indicators and switches or as
complicated as full screen displays and keyboards. There can be at
most one such console. This console sub-unit is represented by the
Console Group in the model. Although most of the information
displayed there is also available in the state of the printer as
represented by the various Groups, it is useful to be able to query
and modify the operator console remotely. For example, a management
application might like to display to its user the current message on
the operator console of the remote printer or the management
application user might like to modify the current message on the
operators console of the remote printer. As another example, one
might have a remote application that puts up a pseudo console on a
workstation screen. Since the rules by which the printer state is
mapped onto the console and vice versa are not standardized, it is
not possible to reproduce the console state or the action of console
buttons and menus. Therefore, the Console Group provides Access to
the console. The operator console is usually implemented on the
system controller with additional hardware for input and display.
2.2.13. Alerts
The alert sub-unit is responsible for detecting reportable events,
making an entry in the alert table and, if and only if the event is a
critical event, initiating a trap. The alert sub-unit is represented
by the Alerts Group and, in particular, the Alert Table. This table
contains information on the severity, sub-unit, detailed location
within the sub-unit, alert code and description of each critical
alert that is currently active within the printer. Each reportable
event causes an entry to be made in the Alert Table.
2.2.13.1. Status and Alerts
Summary information about the state of the printer is reported at
three separate levels: (1) there is the status of the printer as a
whole reported in the Host MIB, (2) there is the status of various
sub-units reported in the principle table of the Group that
represents the sub-unit, and (3) there are alert codes reported in
the Alert Table.
2.2.13.2. Overall Printer Status
Of the many states a printer can be in, certain states are more
"interesting" because of the distinct actions they are likely to
provoke in the administrator. These states may be applied to the
printer as a whole, or to a particular sub-unit of the printer.
These named states are:
Non Critical Alert Active - For the printer this means that one or
more sub-units have a non-critical alert active. For a sub-unit,
this means that the sub-unit has a non-critical alert active.
Critical Alert Active - For the printer this means that one or more
sub-units have a critical alert active. For a sub-unit, this means
that the sub-unit has a critical alert active.
Unavailable - The printer or sub-unit is unavailable for use (this is
the same as "broken" or "down" in other terminologies). A trained
service person is typically necessary to make it available.
Busy / Temporarily Unavailable - The printer or sub-unit is
operational but currently occupied with a request for activity. The
sub-unit will become available without the need of human interaction.
Moving on-line or off-line - The printer is either off-line, in the
process of moving off-line or in the process of moving back on-line;
for example on high end printers reloading paper involves a
transition to off-line to open the paper bin, it is then filled and,
finally, there is a transition back to on-line as the paper bin is
repositioned for printing.
Standby - The printer or sub-unit is unavailable for use because it
is partially powered down and may need some period of time to become
fully operational again. A unit in Standby state shall respond to
network management requests.
The Host MIB provides three status objects that can be used to
describe the status of a printer: (1) hrDeviceStatus in the entry in
the Host MIB hrDeviceTable; (2) hrPrinterStatus in the
hrPrinterTable; and (3) hrPrinterDetectedErrorState in the
hrPrinterTable. These objects describe many of the states that a
printer can be in. The following table shows how the "interesting"
states named above can be recognized by inspecting the values of the
three printer-related objects in the Host MIB:
Printer hrDeviceStatus hrPrinterStatus hrPrinterDetectedErrorState
Status
Normal running(2) idle(3) none set
Busy/ running(2) printing(4)
Temporarily
Unavailable
Non Critical warning(3) idle(3) or could be: lowPaper,
Alert Active printing(4) lowToner, or
serviceRequested
Critical down(5) other(1) could be: jammed,
Alert Active noPaper, noToner,
coverOpen, or
serviceRequested
Unavailable down(5) other(1)
Moving off- warning(3) idle(3) or offline
line printing(4)
Off-line down(5) other(1) offline
Moving down(5) warmup(5)
on-line
Standby running(2) other(1)
These named states are only a subset of the possible states - they
are not an exhaustive list of the possible states. Nevertheless,
several things should be noted. When using these states, it is not
possible to detect when both critical and non-critical alerts are
pending - if both are pending, the Critical Alert Active state will
prevail. In addition, a printer in the Standby state will be
represented in the Host MIB with a device status of running(2) and a
printer status of other(1), a set of states that don"t uniquely
distinguish this important printer state.
Although the above mapping is workable, it would be improved with a
few additions to hrDeviceStatus and hrPrinterStatus in the Host
Resources MIB. In particular, it would be appropriate to add a
"standby" enumeration to hrDeviceStatus. Similarly, it would be
useful to add the following states to hrPrinterStatus: "offline" to
indicate that reason for the printer being down (instead of having to
use "other") which allows both "warning" and "offline" to indicate
going offline and "down" and "offline" to indicate offline and
"notApplicable" to cover cases, such as "standby", where the device
state completely describes the state of the device.
Detailed status per sub-unit is reported in the sub-unit status
fields.
2.2.13.2.1. Host MIB Printer Status
For completeness, the definitions of the Printer Status objects of
the Host MIB are given below:
hrDeviceStatus OBJECT-TYPE
SYNTAX INTEGER {
unknown(1),
running(2),
warning(3),
testing(4),
down(5)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current operational state of the device
described by this row of the table. A value
unknown(1) indicates that the current state of the
device is unknown. running(2) indicates that the
device is up and running and that no unusual error
conditions are known. The warning(3) state
indicates that agent has been informed of an
unusual error condition by the operational software
(e.g., a disk device driver) but that the device is
still "operational". An example would be high
number of soft errors on a disk. A value of
testing(4), indicates that the device is not
available for use because it is in the testing
state. The state of down(5) is used only when the
agent has been informed that the device is not
available for any use."
::= { hrDeviceEntry 5 }
hrPrinterStatus OBJECT-TYPE
SYNTAX INTEGER {
other(1),
unknown(2),
idle(3),
printing(4),
warmup(5)
}
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The current status of this printer device. When
in the idle(1), printing(2), or warmup(3) state,
the corresponding hrDeviceStatus should be
running(2) or warning(3). When in the unknown
state, the corresponding hrDeviceStatus should be
unknown(1)."
::= { hrPrinterEntry 1 }
hrPrinterDetectedErrorState OBJECT-TYPE
SYNTAX OCTET STRING
ACCESS read-only
STATUS mandatory
DESCRIPTION
"This object represents any error conditions
detected by the printer. The error conditions are
encoded as bits in an octet string, with the
following definitions:
Condition Bit # hrDeviceStatus
lowPaper 0 warning(3)
noPaper 1 down(5)
lowToner 2 warning(3)
noToner 3 down(5)
doorOpen 4 down(5)
jammed 5 down(5)
offline 6 down(5)
serviceRequested 7 warning(3)
If multiple conditions are currently detected and
the hrDeviceStatus would not otherwise be
unknown(1) or testing(4), the hrDeviceStatus shall
correspond to the worst state of those indicated,
where down(5) is worse than warning(3) which is
worse than running(2).
Bits are numbered starting with the most
significant bit of the first byte being bit 0, the
least significant bit of the first byte being bit
7, the most significant bit of the second byte
being bit 8, and so on. A one bit encodes that
the condition was detected, while a zero bit
encodes that the condition was not detected.
This object is useful for alerting an operator to
specific warning or error conditions that may
occur, especially those requiring human
intervention."
::= { hrPrinterEntry 2 }
2.2.13.2.2. Sub-unit Status
Sub-unit status is reported in the entries of the principle table in
the Group that represents the sub-unit. For sub-units that report a
status, there is a status column in the table and the value of this
column is always an integer formed in the following way.
The SubUnitStatus is an integer that is the sum of 5 distinct values,
Availability, Non-Critical, Critical, On-line, and Transitioning.
These values are:
Availability value
Available and Idle 0 000"b
Available and Standby 2 010"b
Available and Active 4 100"b
Available and Busy 6 110"b
Unavailable and OnRequest 1 001"b
Unavailable because Broken 3 011"b
Unknown 5 101"b
Non-Critical
No Non-Critical Alerts 0
Non-Critical Alerts 8
Critical
No Critical Alerts 0
Critical Alerts 16
On-Line
Intended state is On-Line 0
Intended state is Off-Line 32
Transitioning
At intended state 0
Transitioning to intended state 64
For example, an input (tray) that jammed on the next to the last page
may show a status of 27 (unavailable because broken (3) + a critical
state (16), jammed, and a noncritical state (8), low paper).
2.2.13.3. Alert Tables
The Alert Group consists of a single table in which all active alerts
are represented. This section provides and overview of the table and
a description of how it is managed. The basic content of the alert
table is the severity (critical or non-critical) of the alert, the
Group and entry where a state change caused the alert, additional
information about the alert (a more detailed location, an alert code,
and a description), and an indication of the level of training needed
to service the alert.
The Alert Table contains some information that is redundant, for
example that an event has occurred, and some information that is only
represented in the Alert Table, for example the additional
information. A single table was used because a single entry in a
Group could cause more than one alert, for example paper jams in more
than one place in a media path. Associating the additional
information with the entry in the affected group would only allow one
report where associating the additional information with the alert
makes multiple reports possible.
Every time an alert occurs in the printer, the printer makes one or
more entries into the Alert Table. The printer determines if an event
is to be classified as critical or non-critical. If the severity of
the Alert is "critical", the printer sends a trap or event
notification to the host indicating that the table has changed.
Whether or not a trap is sent, the management application is expected
to poll the printer on a regular basis and to read and parse the
table to determine what conditions have changed, in order to provide
reliable information to the management application user.
2.2.13.4. Alert Table Management
The alert tables are sparsely populated tables. This means the tables
will only contain entries of the alerts that are currently active and
the number of rows, or entries in the table will be dynamic. More
than one event can be added or removed from the event tables at a
time depending on the implementation of the printer.
There are basically two kinds of events that produce alerts: binary
change events and simple change events. Binary change events come in
pairs: the leading edge event and the trailing edge event. The
leading edge event enters a state from which there is only one exit;
for example, going from running to stopped with a paper jam. The only
exit from this state is fixing the paper jam and it is clear when
that is accomplished. The trailing edge event is the event which
exits the state the was entered by the leading edge event; in the
example above fixing the paper jam is the trailing edge event.
It is relatively straightforward to manage binary change events in
the Alert Table. Only the leading edge event makes an entry in the
alert table. This entry persists in the Alert Table until the
trailing edge event occurs at which point this event is signal by the
removal of the leading edge event entry in the Alert Table. That is,
a trailing edge event does not create an entry; it removes the
corresponding leading edge event. With binary events it is possible
to compute the maximum number that can occur at the same time and
construct an Alert Table that would hold that many events. There
would be no possibility of table overflow and no information about
outstanding events would be lost.
Unfortunately, there are some events that are not binary changes.
This other category of event, the simple change event, is
illustrated by the configuration change event. With this kind of
event the state of the machine has changed, but to a state which is
(often) just as valid as the state that was left and from which no
return is necessary. For example, an operator may change the paper
that is in the primary input source from letter to legal. At some
time in the future the paper may be changed back to letter, but it
might be changed to executive instead. This is where the problem
occurs. It is not obvious how long to keep simple change event
entries in the Alert Table. It they were never removed, the Alert
Table would continue to grow indefinitely.
The agent needs to have an algorithm implemented for the management
of the alert table, especially in the face of combinations of binary
and simple alerts that would overflow the storage capaciity of the
table. When the table is full and a new alert needs to be added, an
old alert needs to be deleted. The alert to be deleted should be
chosen using the following rules:
1. Find a non-critical simple alert and delete it. If there are
multiple non-critical simple alerts, it is suggested that the
oldest one be chosen. If there are no non-critical simple
alerts, then,
2. Find a non-critical binary alert and delete it. If there are
multiple non-critical binary alerts, it is suggested that the
oldest one be chosen. If there are no non-critical binary
alerts, then,
3. Find a critical (binary) alert and delete it. If there are
multiple critical alerts, it is suggested that the
oldest one be chosen. Agent implementors are encouraged to
provide at least enough storage space for the maximum number
of critical alerts that could occur simultaneously. Note that
all critical alerts are binary.
Note that because the Alert Index is a monotonically increasing
integer there will be gaps in the values in the table when an alert
is deleted. Such gaps can be detected by the management application
to indicate that the management application may want to re-acquire
the Printer state and check for state changes it did not observe in
the Alert Table.
2.3. Read-Write Objects
Some of the objects in the printer MIB report on the existence of or
amount of a given resource used with the printer. Some examples of
such resources are the size and number of sheets of paper in a paper
tray or the existence of certain output options. On some printers
there are sensors that allow these resources to be sensed. Other
printers, however, lack sensors that can detect (all of) the
properties of the resource. Because the printer needs to know of the
existence or properties of these resources for the printer to
function properly some other way of providing this information is
needed. The chosen way to solve this problem is to allow a
management application to write into objects which hold the
descriptive or existence values for printers that cannot sense the
values. Thus many of the objects in the MIB are given read-write
access, but a printer implementation might only permit a management
operation to change the value if the printer could not sense the
value itself. Therefore, the ability to change the value of a read-
write object may depend on the implementation of the agent. Note
that even though some objects explicitely state the behaviour of
conditional ability to change values, any read-write object may act
that way.
Generally, an object is given read-write access in the Printer MIB
specification if:
1.The object involves installation of a resource that some
printers cannot themselves detect. Therefore, external means are
needed to inform the printer of the installation. (Here external
means include using the operator console, or remote management
application) and
2.The printer will behave differently if the installation of the
resource is reported than the printer would if the installation
were not reported; that is, the object is not to be used
as a place to put information not used by the printer, i.e., not a
"PostIt". Another way of saying this is that the printer believes
that information given it and acts as if the information were
true. For example, on a printer that cannot sense the size, if
one paper size is loaded, but another size is set into the paper
size object, then the printer will use the size that was
set as its current paper size in its imaging and paper handling.
The printer may get hints that it may not know about the existence or
properties of certain resources. For example, a paper tray may be
removed and re-inserted. When this removal and insertion happens,
the printer may either assume that a property, such as the size of
paper in the tray, has not changed or the printer may change the
value of the associated object to "unknown", as might be done for the
amount of paper in the tray. As long as the printer acts according
to the value in the object either strategy is acceptable.
It is an implementation-specific matter as to whether or not MIB
object values are persistent across power cycles or cold starts. It
is particularly important that the values of the prtMarkerLifeCount
object persist throughout the lifetime of the printer. Therefore, if
the value of any MIB object persists across power cycles, then the
prtMarkerLifeCount object must also persist.
2.4. Enumerations
Enumerations (enums) are sets of symbolic values defined for use with
one or more objects. Some common enumeration sets are assigned a
symbolic data type name (textual convention). These enumerations are
listed at the beginning of this specification.
2.4.1. Registering Additional Enumerated Values
This working group has defined several type of enumerations. These
enumerations differ in the method employed to control the addition of
new enumerations. Throughout this document, references to
"enumeration (n)", where n can be 1, 2 or 3 can be found in the
various tables. The definitions of these types of enumerations are:
enumeration (1) All the values are defined in the Printer MIB
specification (RFCfor the Printer MIB). Additional enumerated
values require a new RFC.
enumeration (2) An initial set of values are defined in the Printer
MIB specification. Additional enumerated values are
registered after review by this working group. The initial
versions of the MIB will contain the values registered so far.
After the MIB is approved, additional values will be
registered through IANA after approval by this working group.
enumeration (3) An initial set of values are defined in the Printer
MIB specification. Additional enumerated values are
registered without working group review. The initial versions of
the MIB will contain the values registered so far. After the MIB
is approved, additional values will be registered
through IANA without approval by this working group.
3. Objects from other MIB Specifications
This section lists the objects from other IETF MIB specifications
that are mandatory for conformance to this Printer MIB specification.
3.1. System Group objects
All objects in the system group of MIB-II (RFC1213) must be
implemented.
3.2. System Controller
The System Controller is represented by the Storage and Device Groups
of the Host Resources MIB (RFC1514). These are the only groups that
are required to be implemented. Other Groups (System, Running
Software, Running Software Performance, and Installed Software) may
be implemented at the discretion of the implementor.
3.3. Interface Group objects
All objects in the Interfaces Group of MIB-II (RFC1213) shall be
implemented.
Printer-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, experimental, Counter32, Integer32,
TimeTicks, NOTIFICATION-TYPE, OBJECT-IDENTITY FROM SNMPv2-SMI
TEXTUAL-CONVENTION FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF
hrDeviceIndex, hrStorageIndex FROM HOST-RESOURCES-MIB;
printmib MODULE-IDENTITY
LAST-UPDATED "9411250000Z"
ORGANIZATION "IETF Printer MIB Working Group"
CONTACT-INFO
" Steven Waldbusser
Postal: Carnegie Mellon University
4910 Forbes Ave
Pittsburgh, PA, 15213
Tel: 412-268-6628
Fax: 412-268-4987
E-mail: waldbusser@cmu.edu"
DESCRIPTION
"The MIB module for management of printers."
::= { mib-2 43 }
-- Textual conventions for this MIB module
MediaUnit ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Units of measure for media dimensions."
-- This is a type 1 enumeration.
SYNTAX INTEGER {
tenThousandthsOfInches(3), -- .0001
micrometers(4)
}
CapacityUnit ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Units of measure for media capacity."
-- This is a type 1 enumeration.
SYNTAX INTEGER {
tenThousandthsOfInches(3), -- .0001
micrometers(4),
sheets(8),
feet(16),
meters(17)
}
SubUnitStatus ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Status of a printer sub-unit.
The SubUnitStatus is an integer that is the sum of 5
distinct values, Availability, Non-Critical, Critical,
On-line, and Transitioning. These values are:
Availability value
Available and Idle 0 000"b
Available and Standby 2 010"b
Available and Active 4 100"b
Available and Busy 6 110"b
Unavailable and OnRequest 1 001"b
Unavailable because Broken 3 011"b
Unknown 5 101"b
Non-Critical
No Non-Critical Alerts 0
Non-Critical Alerts 8
Critical
No Critical Alerts 0
Critical Alerts 16
On-Line
Intended state is On-Line 0
Intended state is Off-Line 32
Transitioning
At intended state 0
Transitioning to intended state 64
"
SYNTAX INTEGER (0..126)
PresentOnOff ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Presence and configuration of a device or feature."
-- This is a type 1 enumeration.
SYNTAX INTEGER {
other(1),
on(3),
off(4),
notPresent(5)
}
CodedCharSet ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A coded character set value that specifies both a set of
characters that may be used and an encoding (as one or more
octets) that is used to represent the characters in the
set. These values are to be used to identify the encoding
employed for strings in the MIB where this is not fixed by
the MIB.
Some objects that allow a choice of coded character set
are: the prtLocalizationCharacterSet object in the
LocalizationTable and prtInterpreterDefaultCharSetIn.
The prtGeneralCurrentLocalization and prtConsoleLocalization
objects in turn contain the index in the LocalizationTable
of the current localization (country, language, and coded
character set) of the `description" objects and the console,
respectively.
The space of the coded character set enumeration has been
divide into three regions. The first region (3-999) consists
of coded character sets that have been standardized by some
standard setting organization. This region is intended for
standards that do not have subset implementations. The
second region (1000-1999) is for the Unicode and ISO/IEC 10646
coded character sets together with a specification of a (set
of) sub-repetoires that may occur. The third region (>1999)
is intended for vendor specific coded character sets.
NOTE: Unicode and ISO 10646 character coded data may be
processed and stored in either Big Endian (most significant
octet first) or Little Endian (least significant octet
first) order. Intel x86, VAX, and Alpha/AXP architectures are
examples of Little Endian processor architectures.
Furthermore, in environments where either order may occur,
so-called Unicode BYTE ORDER MARK (BOM) character (which is
ISO 10646 ZERO WIDTH NO BREAK SPACE), coded as FEFF in two
octets and 0000FEFF in four octets is used at the beginning
of the data as a signature to indicate the order of the
following data (See ISO 10646 Annex F). Thus either
ordering and BOM may occur in print data streams sent to the
interpreter. However, ISO 8824/8825 (ASN.1/BER) used by
SNMP is quite clear that Big Endian order shall be used and
BOM shall NOT be used in transmission in the protocol.
Transmitting Unicode in Big Endian order in SNMP should
not prove to be a hardship for Little Endian machines,
since SNMP ASN.1/BER requires integers to be transmitted
in Big Endian order as well. So SNMP implementations on
Little Endian machines are already reversing the order of
integers to make them Big Endian for transmission via
SNMP. Also Unicode characters are usually treated as
two-octet integers, not short text strings, so that it will
be straightforward for Little Endian machines to reverse the
order of Unicode character octets as well before
transmitting them and after receiving them via the SNMP
protocol.
Where a given coded character set may be known by more than
one name, the most commonly known name is used as the name
of the enumeration and other names are shown in the
comments. The comments also indicate where to find detailed
information on the coded character set and briefly
characterize its relationship to other similar coded
character sets.
The current list of character sets and their enumerated
values used to reference them is contained in the IANA
Character Set registry. The enum value is indicated by
the MIBenum entry in the registry. The enum symbol is
indicated by the Alias that starts with `cs" for character
set.
The IANA character sets registry is available via
anonymous FTP.
The ftp server is ftp.isi.edu.
The subDirectory is /in-notes/iana/assignments/.
The file name is character-sets.
To add a character set to the IANA Registry:
1. Format an entry like those in the current list,
omitting the MIBenum value.
2. Send the entry with a request to add the entry
to the character set list to iana@ISI.EDU.
3. The IANA will supply a unique MIBenum value
and update the list."
-- This is a type 3 enumeration.
SYNTAX INTEGER {
other(1) -- used if the designated coded
-- character set is not currently in
-- the enumeration
-- See IANA Registry for standard character sets in the
-- MIBenum range of 3-999.
-- See IANA Registry for Unicode and vendor-supplied
-- combinations of ISO collections and character sets based
-- on Unicode in the MIBenum range of 1000-1999.
-- See IANA Registry for vendor developed character sets
-- in the MIBenum range of 2000-xxxx.
}
-- The General Printer Group
--
-- The general printer sub-unit is responsible for the overall control
-- and status of the printer. There is exactly one general printer
-- sub-unit in a printer.
--
-- Implementation of every object in this group is mandatory.
prtGeneral OBJECT IDENTIFIER ::= { printmib 5 }
prtGeneralTable OBJECT-TYPE
SYNTAX SEQUENCE OF PrtGeneralEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table of general information per printer.
Objects in this table are defined in various
places in the MIB, nearby the groups to
which they apply. They are all defined
here to minimize the number of tables that would
otherwise need to exist."
::= { prtGeneral 1 }
prtGeneralEntry OBJECT-TYPE
SYNTAX PrtGeneralEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry exists in this table for each
device entry in the hostmib device table who"s type
is `printer""
INDEX { hrDeviceIndex }
::= { prtGeneralTable 1 }
PrtGeneralEntry ::= SEQUENCE {
-- Note that not all of the objects in this sequence are in the
-- general printer group.
prtGeneralConfigChanges Counter32,
prtGeneralCurrentLocalization Integer32,
prtGeneralReset INTEGER,
prtGeneralCurrentOperator OCTET STRING,
prtGeneralServicePerson OCTET STRING,
prtInputDefaultIndex Integer32,
prtOutputDefaultIndex Integer32,
prtMarkerDefaultIndex Integer32,
prtMediaPathDefaultIndex Integer32,
prtConsoleLocalization Integer32,
prtConsoleNumberOfDisplayLines Integer32,
prtConsoleNumberOfDisplayChars Integer32,
prtConsoleDisable INTEGER
}
prtGeneralConfigChanges OBJECT-TYPE
SYNTAX Counter32
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Counts configuration changes that change the capabilities of
a printer, such as the addition/deletion of input/output bins,
the addition/deletion of interpreters, or changes in media
size. Such changes will often affect the capability of the
printer to service certain types of print jobs.
Management applications may cache infrequently changed
configuration information about sub-units on the printer.
This object should be incremented whenever the agent wishes
such applications to invalidate that cache and re-download
all of this configuration information, thereby signalling a
change in the printer"s configuration.
For example, if an input tray that contained paper of
different dimensions was added, this counter would be
incremented.
As an additional example, this counter would not be
incremented when an input tray is removed or the level of an
input device changes."
::= { prtGeneralEntry 1 }
prtGeneralCurrentLocalization OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value of the prtLocalizationIndex corresponding to the
current language, country, and character set to be used for
localized string values that are identified as being dependent
on the value of this object. Note that this object does not
apply to localized strings in the prtConsole group or any
object that is not identified as above."
::= { prtGeneralEntry 2 }
prtGeneralReset OBJECT-TYPE
-- This value is a type 3 enumeration
SYNTAX INTEGER {
notResetting(3),
powerCycleReset(4), -- Cold Start
resetToNVRAM(5), -- Warm Start
resetToFactoryDefaults(6) -- Reset contents of
-- NVRAM to factory defaults
}
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"Setting this value to `powerCycleReset", `resetToNVRAM", or
`resetToFactoryDefaults" will result in the resetting of the
printer. When read, this object will always have the value
`notResetting(3)", and a SET of the value `notResetting" shall
have no effect on the printer. Some of the defined values are
optional. However, every implementation must support at least
the values `notResetting" and resetToNVRAM"."
::= { prtGeneralEntry 3 }
-- The Cover Table
--
-- The cover portion of the General print sub-unit describes the
-- covers and interlocks of the printer. The Cover Table has an
-- entry for each cover and interlock.
prtCover OBJECT IDENTIFIER ::= { printmib 6 }
prtCoverTable OBJECT-TYPE
SYNTAX SEQUENCE OF PrtCoverEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table of the covers and interlocks of the printer."
::= { prtCover 1 }
prtCoverEntry OBJECT-TYPE
SYNTAX PrtCoverEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information about a cover or interlock.
Entries may exist in the table for each device
index whose device type is `printer"."
INDEX { hrDeviceIndex, prtCoverIndex }
::= { prtCoverTable 1 }
PrtCoverEntry ::= SEQUENCE {
prtCoverIndex Integer32,
prtCoverDescription OCTET STRING,
prtCoverStatus INTEGER
}
prtCoverIndex OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A unique value used by the printer to identify this Cover
sub-unit. Although these values may change due to a major
reconfiguration of the device (e.g. the addition of new
cover sub-units to the printer), values are expected to
remain stable across successive printer power cycles."
::= { prtCoverEntry 1 }
prtCoverDescription OBJECT-TYPE
SYNTAX OCTET STRING (SIZE(0..255))
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The manufacturer provided cover sub-mechanism name in the
localization specified by prtGeneralCurrentLocalization."
::= { prtCoverEntry 2 }
prtCoverStatus OBJECT-TYPE
-- This value is a type 2 enumeration
SYNTAX INTEGER {
other(1),
doorOpen(3),
doorClosed(4),
interlockOpen(5),
interlockClosed(6)
}
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The status of this cover sub-unit."
::= { prtCoverEntry 3 }
-- The Localization Table
--
-- The localization portion of the General printer sub-unit is
-- responsible for identifying the natural language, country, and
-- character set in which character strings are expressed. There
-- may be one or more localizations supported per printer. The
-- available localizations are represented by the Localization table.
prtLocalization OBJECT IDENTIFIER ::= { printmib 7 }
prtLocalizationTable OBJECT-TYPE
SYNTAX SEQUENCE OF PrtLocalizationEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The available localizations in this printer."
::= { prtLocalization 1 }
prtLocalizationEntry OBJECT-TYPE
SYNTAX PrtLocalizationEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A description of a localization.
Entries may exist in the table for each device
index who"s device type is `printer"."
INDEX { hrDeviceIndex, prtLocalizationIndex }
::= { prtLocalizationTable 1 }
PrtLocalizationEntry ::= SEQUENCE {
prtLocalizationIndex Integer32,
prtLocalizationLanguage OCTET STRING,
prtLocalizationCountry OCTET STRING,
prtLocalizationCharacterSet CodedCharSet
}
prtLocalizationIndex OBJECT-TYPE
SYNTAX Integer32 (1..65535)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A unique value used by the printer to identify this
localization entry. Although these values may change due to a
major reconfiguration of the device (e.g., the addition of new
Cover sub-units to the printer), values are expected to remain
stable across successive printer power cycles."
::= { prtLocalizationEntry 1 }
prtLocalizationLanguage OBJECT-TYPE
SYNTAX OCTET STRING (SIZE(0..2))
MAX-ACCESS read-only
STATUS current
DESCRIPT