Subject: Comments on draft-ietf-bmwg-mswitch-02

From: "David Newman" <[email-masked]>
Date: Sun, 27 Feb 2000 18:12:27 -0500

In general I approve of the progress made in draft 02. A few specific
comments:

5.5  Congestion Control

As noted in RFC 2285 section 3.7, backpressure is not the only means of
congestion control mechanism. Some switches implement forward pressure, and
some use a too-short IFG. This is a terminology nit, but for the purposes of
completeness it may be more accurate to refer throughout this document to
"congestion control," of which backpressure is one example.

Appendix B: Generating Offered Load
B.1 Frame Based Load

The third paragraph states that "All ports MAY NOT transmit the same number
of frames if their Iload is not the same.  An example would be the Partially
meshed overloading test." Not sure I follow here -- I don't see anything in
the partially meshed traffic test descriptions suggesting procedures where
different ports will have different Iloads. Have I missed something?

The final paragraph states that "Oload per port MAY be reported for
diagnostic purposes." Per-port Oload may be intrinsically interesting, for
example in determinining whether Oload variation exists across multiple
ports. I would delete the words "for diagnostic purposes" since per-port
Oload itself may be a useful measurement.

B.2 Time Based Load

The fourth paragraph states that "all ports SHOULD stop transmitting frames
after the specified trial duration, within 100 PPM." This is the first
reference to a PPM metric. What is the unit of measurement here?

David Newman