Early Review of draft-ietf-nmop-terminology-07
review-ietf-nmop-terminology-07-secdir-early-orman-2024-11-13-00

To: iesg@ietf.org, secdir@ietf.org
Cc: draft-ietf-nmop-terminology.all@ietf.org
Subject: Security directorate review of draft-ietf-nmop-terminology-06
--text follows this line--
       	             Security review of 
       Some Key Terms for Network Fault and Problem Management
		    draft-ietf-nmop-terminology-06
Do not be alarmed.  I generated this review of this document as part
of the security directorate's ongoing effort to review all IETF
documents being processed by the IESG.  These comments were written
with the intent of improving security requirements and considerations
in IETF drafts.  Comments not addressed in last call may be included
in AD reviews during the IESG review.  Document editors and WG chairs
should treat these comments just like any other early review comments.
The selection of the "key terms" for definition was mysterious to me
as I read the draft.  Reading over the mailing list, I've come to
see that it is conceived as a companion document for all the NMOP
documents, and the terms were derived from that collection.  The
definitions help ensure that the document collection has consistent
terminology.  That, however, is undermined by the awkwardness of
the definitions.
This is a laudable effort to facilitate communication by acting on the
adage "define your terms".  Those definitions have to shine with
clarity if they are to be useful.  But if instead, the definitions are
per se confusing, then there is no advantage, and it would be better
to proceed on the assumption that the words have their ordinary
dictionary meanings.  Much of this document lacks clarity, as
illustrated by the following samples.
"A characteristic may be considered with respect to the concept
of dimensional that is built on facts (see 'value', below) and
dimensions (the contexts and descriptors that identify and give
meaning to the facts)."
I cannot interpret that sentence.  "Dimensional analysis",
perhaps?  Still, it is opaque, and I recommend deleting it.  The next
sentence says that "metric" is a synonym for "characteristic".  Amend
the preceding sentence "Characteristic: Observable or measurable
aspect or behavior associated with a resource."  to "Characteristic:
Observable or measurable aspect or behavior associated with a
resource.  I.e., a metric."
"Value: A measurable amount which may be in the form of an integer
      (e.g., a count) or on a continuous variable (e.g., an analogue
      measurement) associated with a characteristic."
Awkward phrasing.  A value is a measured amount that can be integer or
rational.  A value is the measurement of a resource.  That resource
might be associated with a characteristic, or it might not, or it
might be associated with many characteristics.  Must a value be a
number?  Could it be one of "{low, medium, high}", for example?  That
might happen if a vendor supplies a "measurement" with those values.
"Resource:  A component, commodity, service, or capability that can be
      used to support the delivery of some function."
What does the "delivery of some function" mean?  "Function" is not a
defined term.  I suspect that a "resource" is more succinctly defined
as a "component of a system".  Further definitions suggest that a
resource must have at least one "characteristic" (i.e., metric), so 
a resource is a system component with one or more metrics.  Are there
system components without metrics?  Are they resources?  I'm not sure.
"Change:  In the context of monitoring network resources, the
      variation in values associated with a characteristic of a resource
      at a specific time or over time.
      *  Most changes are not noteworthy (i.e., are not relevant).
      *  Perception of change depends upon detection, the sampling
         rate/accuracy/detail, and perspective."
First, it's not a good idea to redefine an ordinary, simple word
("change") to have a particular meaning.  It results in people having
to say "I mean 'change' in the sense of terminology document, not in
the sense of ordinary English" or vice versa.  Beyond that, the
definition is awkward.  You can just say "a variation in a value or a
history of those variations."  A value is associated with a time,
so there's no need to use "time" as part of the definition of "change".
Why is the statement that "most changes are not noteworthy" part of
the *definition*??  "Perception of change" sounds like "if a tree
falls in the forest" conundrum.  The text is redundant and unhelpful.
"Event:  The change in value (of a characteristic of a resource)"
"Compared with a change, which is over a period of time, an
         event happens at a measurable instant."  
But an event is here *defined* as a "change".  It's a change but not a change?
What is a "measurable instant"?  It's not the instant that's being
measured, it's the value at a time.
Etc.