-----Original Message-----
From: Nelson, David [mailto:dnelson@enterasys.com]
Sent: Friday, March 03, 2006 16:40
To: Wijnen, Bert (Bert); radiusext@ops.ietf.org
Subject: RE: AD review: radius dynauth client/server mib documents
Bert Wijnen writes...
2. The a whole serioes of Counter32 objects.
I wonder what the object is to indicate a counter-discontinuity?
Or can such only happen at system restart/reboot?
See RFC2578 that explains this in sect 7.1.6
RFC4181, sect 4.6.1.2 (1st bullet) also speaks to it.
RFC2578 Section 7.1.6:
The Counter32 type represents a non-negative integer which
monotonically increases until it reaches a maximum value of 2^32-1
(4294967295 decimal), when it wraps around and starts increasing
again from zero.
Counters have no defined "initial" value, and thus, a
single value of
a Counter has (in general) no information content. Discontinuities
in the monotonically increasing value normally occur at re-
initialization of the management system, and at other times as
specified in the description of an object-type using this
ASN.1 type.
If such other times can occur, for example, the creation
of an object
instance at times other than re-initialization, then a
corresponding
object should be defined, with an appropriate SYNTAX clause, to
indicate the last discontinuity. Examples of appropriate SYNTAX
clause include: TimeStamp (a textual convention defined in [3]),
DateAndTime (another textual convention from [3]) or TimeTicks.
RFC4181 Section 4.6.1.2 (1st bullet):
- It is OK to use Counter32/64 for counters that may/will be reset
when the management subsystem is re-initialized or when other
unusual/irregular events occur (e.g., counters
maintained on a line
card may be reset when the line card is reset).
However, if it is
possible for such other unusual/irregular events to occur, the
DESCRIPTION clause MUST state that this is so and MUST describe
those other unusual/irregular events in sufficient detail that it
is possible for a management application to determine whether a
reset has occurred since the last time the counter was
polled. The
RECOMMENDED way to do this is to provide a discontinuity
indicator
as described in RFC 2578 Sections 7.1.6 and 7.1.10. For
an example
of such a discontinuity indicator, see the
ifCounterDiscontinuityTime object in the IF-MIB [RFC2863].
So I take it that the normal wrapping from maximum value to
zero is OK,
and reset upon system (re)initialization is OK, but any other
"discontinuity" needs special attention. Is that right?