Subject: RE: Alarm #40 - Potential Solution

From: Randy Presuhn <[email-masked]>
Date: Wed, 1 May 2002 17:16:38 -0700 (PDT)

Hi -

As a technical contributor...

> Date: Fri, 26 Apr 2002 16:50:34 -0700 (PDT)
> From: Randy Presuhn <rpresuhn>
> Message-Id: <[email-masked]>
> To: [email-masked]
> Subject: RE: Alarm #40 - Potential Solution
...

As you may recall, I gave three examples of how the addition
of alarmModelVarbindSubtree  alarmModelResourceSubtree  objects
to the model table would handle some interesting cases of
resource identification without magic.  Here's an additional
example, which addresses the concern raised by Stefan when he wrote:

> From: "Stefan Wallin" <[email-masked]>
> To: <[email-masked]>
> Subject: Pairing instances in RMON example
> Date: Tue, 23 Apr 2002 16:43:29 +0200
> Message-ID: <[email-masked]>
> In-Reply-To: <[email-masked]>
...
> 2) However the more general question is:
> Lets say I define two alarms in the RMON alarmTable:
> alarmVariable X, risingThreshold 10, fallingthreshold 8
> alarmVariable Y, risingThreshold 20, fallingthreshold 16
> 
> In this case it is extremely important that fallingAlarm Threshold on Y
> does not clear any active alarm on X.
...

Let's assume that Stefan's "X" is monitored by row 101 in
the RMON alarmTable, and that "Y" is monitored by row 202 in
the RMON alarmTable.  Furthermore, let's a assume that the
resource for "X" is ifEntry number 42, and that the resource
for "Y" is upsInputEntry number 13.

The strawman I proposed could actually handle this without
any appeals to magic.  The alarmModelEntries for the "X"
alarms would have

   alarmModelVarbindSubtree  = 1.3.6.1.2.1.16.3.1.1.1.101
   alarmModelResourceSubtree = 1.3.6.1.2.1.2.2.1.1.42

The entries for "Y" would have

   alarmModelVarbindSubtree  = 1.3.6.1.2.1.16.3.1.1.1.202
   alarmModelResourceSubtree = 1.3.6.1.2.1.33.1.3.3.1.2.13

Neat, huh?  The cool thing about this is that it lets the
application configuring the alarmModels do things like
monitor temperature thresholds and associate the alarm with
the cooling system, rather than the sensor.  Of course, this
also works with things like the expression MIB.

 ------------------------------------------------------
 Randy Presuhn          BMC Software, Inc.  1-3141
 [email-masked]  2141 North First Street
 Tel: +1 408 546-1006   San José, California 95131  USA
 ------------------------------------------------------
 My opinions and BMC's are independent variables.
 ------------------------------------------------------