Subject: Last Call comment on <draft-ops-smiv2-tc-00.txt>

From: John Flick <[email-masked]>
Date: Tue, 8 Dec 1998 20:25:57 -0800 (PST)

Discussion on the snmpv3 mailing list last week indicated that there
is a section of the "Textual Conventions for SMIv2" document that has
been frequently misinterpreted, and should probably be clarified.

The state transition table for the RowStatus textual convention has
been misinterpreted by many implementors to mean that transitions from 
notInService to active MUST succeed.  This interpretation would
require that a row cannot be in the notInService state unless it is
internally consistent, consistent with the current state of the
system, and resources are known to be available to make it active.
It also leads to a misinterpretation of the notReady state, which was
intended to mean that there are columns missing that need to be
created before the row is made active.

This issue was discussed on the snmpv2 mailing list back in May 1996,
with the conclusion that:

  - notReady means that columns are missing.  A row where all columns
    exist cannot be notReady
  - a row cannot transition from notInService to notReady
  - notInService has no implication regarding the internal consistency 
    of the row, availability of resources, or consistency with the
    current state of the system
  - the note:
            NOTE: Other processing of the set request may result in a
            response other than noError being returned, e.g.,
            wrongValue, noCreation, etc.
    applies to the entire state table, and means that
    notInService->active is allowed to fail.

However, this interpretation is still not clear in the draft (the
relevant text is unchanged from RFC 1903).  Discussion on the snmpv3
mailing list in the last week indicates that some implementors are
still misinterpreting this.

I feel that it would be wise to add clarifying text to the description 
of the RowStatus TC regarding the above points, and that the cell in
the state transition table for the transition from
notInService->active should refer to a note containing clarification
that the transition may fail.

Thanks,
John

---

From: "David T. Perkins" <[email-masked]>
Date: Thu, 10 Dec 1998 01:51:53 -0500

John,

Thank you for your helpful message. The three of us updating the SMI
documents agree with your interpretation of the Textual Conventions
document. We plan to update the document to change the text "make"
to "attempt to make" on the top of page 9 and the middle of page 16.
We also plan to update the note (that you pointed out) at the bottom of the
state diagram. The change to the note will add text to say that it applies
to any variable including the "RowStatus" column of the table.

---

From: "David T. Perkins" <[email-masked]>
Date: Thu, 10 Dec 1998 01:51:53 -0500

John,