Date: Fri, 21 Nov 2008 12:59:06 -0500
To: pmol at ietf.org
From: Al Morton <acmorton at att.com>
Subject: Comment on framework 01
Alan,
As we discussed yesterday, please consider this comment as part of the
WG Last Call (message to follow):
Section 3.4.3
...
(iv) Reporting Model
The Reporting Model definition is intended to make any relationship
between the metric and the reporting model clear. There are often
implied relationships between the method of reporting metrics and the
metric itself, however these are often not made apparent to the
implementor. For example, if the metric is a short term running
average packet delay variation (e.g. PPDV as defined in RFC3550)
however this value is reported at intervals of 6-10 seconds
this results in a sampling model which may have limited accuracy if
packet delay variation is non-stationary.
I suggest we use the metric name from RFC 3550 to help people find
the reference there, as follows:
... For example, if the metric is a short term running
average source-to-receiver packet spacing difference
(e.g. D(i,j) as defined in RFC3550), then
the value is typically reported at intervals of 6-10 seconds.
This reporting frequency results in a sampling model which
may have limited accuracy if the inter-packet delay variation
is non-stationary.
Al