Subject: [bmwg] Some FIB benchmarking terminology draft comments.

From: Kevin Dubray <[email-masked]>
Date: Tue, 10 Jul 2001 14:03:28 -0400

Here's some feedback on the FIB terminology draft.  

In the first paragraph of the overview, Section 2, the third sentence
states: "As FIB sizes increase, and as FIB prefix distributions tend
towards longer network prefixes, then it will take more time to match
the destination address... " While this might be an expected outcome, it
is not necessarily a tautology. (Do you mean to imply that if I add one
additional prefix to the FIB, there will always be a discernible
increase in whatever is being measured?) Aligning this wording to
diction similar in section 5.5 may be satisfactory.  However, I think
the point trying to be made here is: It is important to assess the
performance impact on routers with respect to these two primary factors
(FIB size and prefix Distribution) affecting the FIB.

In that same paragraph, the note "(error! Reference was not found. )"
will need to be resolved.  

The second and third paragraphs of the overview present methodological
considerations.  These considerations might not be appropriate for an
overview.  If these considerations are critical to the terminology
document, then they should be moved to the specific metric definition(s)
to which they applied.  

Regarding section 5.1, network prefix: 

You seem to paraphrase a definition presented in section 2.2.5.2 of RFC
1812.  The Internet draft <draft-berkowitz-bgpcon-01.txt> appears to
take more a direct approach by explicitly quoting the definition. 
Perhaps you could align the two efforts by following suit? 

If in the discussion section, if you bind the notion of prefix length to
the network prefix, you help with the flow of the terms, reinforce a
important concept, and build the segue into the "/" shorthand.

A nit.  Somehow the construct: 

"Definition: 
     See Section 2.2.5. ...  

A network prefix ..."  

Just doesn't seem right.  Perhaps putting the actual definition under
the header would be more straightforward.  Keep only definitions in the
definition section.  Put parenthetical statements (E.g.,  This
definition is taken/paraphrased/whatever from section 2.2.5.2 of RFC
1812. ) 

Regarding Section 5.2, network prefix length:

It might be helpful in the discussion if you introduce the notion that
prefixes of the same length are often grouped or discussed as an
equivalence class. (E.g., the /8 prefixes, 100 /16 prefixes)  This may
help build a bridge for section 5.7. 

Section 5.3, FIB: 

Must the wording regarding FIB size and FIB entries be a necessary
component of the definition you cite from Appendix B of RFC 1812? Can
you move the importance of these attributes to the discussion section? 

Section 5.4, forwarding information base entry:
  
Is it necessary to prescribe the contents of the FIB entry? Or was it
your intent to cite what you consider to be typical FIB entry
components? Alternatively, would it be sufficient to say: A FIB entry
atomically contains the required information to make a forwarding
decision regarding an associated prefix - and then provide what you
consider to be typical (minimal?) FIB entry components in the
discussion? 

Lastly, a table of contents would be most beneficial for this document. 
This had been suggested numerous times.  

While, admittedly, many of these issues seek to clarify/simplify and are
otherwise minor, I don't feel that this draft should be advanced for AD
review until issues regarding alignment of the terms overlapping other
efforts are adequately addressed.  We're very close, but not quite
there, IMHO.

-Kevin

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---

From: "TROTTER,GUY (A-Canada,ex1)" <[email-masked]>
Date: Thu, 19 Jul 2001 15:52:00 -0400

Hi Kevin,

To answer your specific comments ...

> Here's some feedback on the FIB terminology draft.  

Thanks!

> (FIB size and prefix Distribution) affecting the FIB.

I've reworded this - see the new version (to be distributed momentarily).

> will need to be resolved.  

Fixed!

> document, then they should be moved to the specific metric 

I'd like to keep these two paragraphs in the intro.  They put some of the
definitions into context, although I'll admit that they do imply
methodology.  A chicken and egg thing - the methodology implies a
definition, and the definition makes more sense if the methodology (in very
general terms) is understood.
 
> Perhaps you could align the two efforts by following suit? 

Done.

> important concept, and build the segue into the "/" shorthand.

Done.

> definition is taken/paraphrased/whatever from section 2.2.5.2 of RFC

Done.

> help build a bridge for section 5.7. 

Done.

> you move the importance of these attributes to the discussion 

Done.

> consider to be typical (minimal?) FIB entry components in the

Good point.  Done.

> This had been suggested numerous times.  

Done.

> efforts are adequately addressed.  We're very close, but not quite

What do we have to do to clarify this?

Thanks,

Guy