Subject: PMP> Lets change "optional" to "conditionally mandatory"

From: Tom Hastings <[email-masked]>
Date: Wed, 2 Apr 1997 10:54:37 PST

I thought that the PMP had been counseled that the IETF abhors optional
groups.  So I thought we had agreed to change all current groups from
"optional" to "conditionally mandatory".  My understanding of conditionally
mandatory is that if a printer has the feature than it is mandatory
for the agent to instrument that feature in the MIB, i.e., is mandatory
for the agent to implement the conditionally mandatory group.
Conversely, if the implementation does not have the feature represented
by a conditionally mandatory group, then the agent need not implement that 
group.

So there are a number of comments in the group block comments, such as page
67 for the (new) Auxiliary Sheet Group which says:

  -- This group is optional.  However, to claim conformance to this
  -- group it is necessary to implement every object in this group.

and page 79 for the (old) Extended Input Group which says the same thing.

Page 134 lists all the groups that are not mandatory and says that
they are optional:

              -- the prtResponsiblePartyGroup, prtExtendedInputGroup,

              -- prtInputMediaGroup, prtExtendedOutputGroup,

              -- prtOutputDimensionsGroup, prtOutputFeaturesGroup,

              -- prtMarkerSuppliesGroup, prtMarkerColorantGroup,

              -- prtAuxiliarySheetGroup, and the

              -- prtInputSwitchingGroup are completely optional.

              ::= { prtMIBConformance 1 }

I suggest changing "optional" to "conditionally mandatory" and
"completely optional" to "conditionally mandatory".

I also found that the prtAlertTime indicates "(optional)" on page 112,
but we have changed to make prtAlertTime part of the mandatory
Alert group, so delete the "(optional)" on page 112.

For the uninitiated, I suggest we define conditionally mandatory
in the Terminology appendix as:

Conditionally Mandatory - The conformance requirement for a group that
requires a conforming agent to implement the group if the
printer has the feature represented by the group, i.e., the group
becomes mandatory.  Conversely, if the printer does not have the feature 
represented by a conditionally mandatory group, then the agent need not 
implement that group.

---

From: Lloyd Young <[email-masked]>
Date: 2 Apr 97 22:27:31 EST

Tom,
There are two new RFC's out now (RFC 1904 - Conformance Statements for Version
2 of the Simple Network Management Protocol and RFC 2119 - Key words for use
in RFCs to Indicate Requirement Levels) that say that "optional" is OK. We 
decided
in this morning PMP session to leave the optional groups as optional.
Lloyd