Administrator Handbook Table of contents version française

SNMP Table Auditor

Introduction

This directory plugin of LoriotPro is a very powerful solution for monitoring and finding network troubles and network usage trend of a huge number of SNMP objects located in a SNMP Table or in predefined list of SNMP object.

It can be used for auditing any set of separate SNMP objects or a SNMP table. It can be or not related to network devices.

The following example displays the etherstatsentry of the RMON table of an ethernet switch. The etherStatsTable collects a variety of counts for each attached subnetwork, including byte, packet,error and frame size count.

Audit RMON etherstat table

A click on a cell displays the last values and the current graph (example on the ifxentry of the ethernet switch)

Graph attached

Arrows indicates the global trend of the SNMP value since the start time.

arrow up The value is increasing most of the time. Since the start time the number of changes between to successive samples toward a higher value are greater than the number of change toward a lower value.
arrow stable The value stays constante
arrow down The value is decreasing most of the time. Since the start time the number of changes between to successive samples toward a lower value are greater than the number of change toward a higher value.


The background color of a table cell indicates the ratio between the total number of samples and the total number of changes. A dark red color indicates that 100 % of the samples collected contains changes and the light red indicates that few changes have occurred.

back color

The following graphic shows how the trend (and the type of arrow assigned) is calculated. The sum of the positive deltas is compare to the sum of the negative deltas. Deltas are obtained by subtraction of the current collected value and the preceding collected value.

audit concept

Installation

The installation of a Directory plugin is explained in this chapter

Configuration

The SNMP values to display can be taken in a SNMP table object or in aSNMP list of object. SNMP list are define as sci file and can be created with the sci script editor. sci files are simple text file that contains snmp objects with their index, one per line.

To open a new audit form a SNMP table select the menu option

Files>Set new audit table

The SNMP table selection Wizard is dispalyed

snmp table wizard

Click on OK when a table is selected.

Click on the start button to start the collection of values.

To use a sci file you should first define the sci. You can simply use a text editor and add you objects.

example of sci file and table audit:

sci exemple     sci result

The sci file should containts the selected snmp objects (switch port objects) and their index.

Interpreting results

In the following example we have selected the hrProcessorEntry table that displays the usage of a dual CPU systemin our example.

The hrprocessorLoad SNMP object is a gauge. The value can increase or decrease between 0 to 100.

processor table

If we click on the cell the graph below is displayed. By default the graph uses the differential mode. The points of the graph are the delta between the current value and the preceding one.

gauge object

If you check the No differential checkbox the graph will display the value of the CPU usage and no the delta.

gauge no diff

The information in the top pane displays the calculated values.

The Change number value displays the number of changes and the number of samples

The Change % value display the ratio of the change number and is used to define the background color.

 


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