CRC error monitoring in Interface for device with model SNS-3515-ACS-K9

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

We have to enable monitoring of CRC errors in Interface for below model:

SNS-3515-ACS-K9

From device team's TAC we got some input which needs to be considered for setting up alarms threshold.

Below is the statement we are referring to:

When considering the change in value between 2 polling cycles, it's up to you to determine how many errors would be considered an Alarm condition, and this will depend on the polling cycle you are using. Eg an increase of 10 or more over a 5 minute polling cycle may be considered as an Alarm, but a similar increase over a 1 hour polling cycle may not be considered as an Alarm.

So, how can we achieve this.

Environment

UIM : 20.3

Component : UIM - SNMPCOLLECTOR

Resolution

The data polling module for snmpcollector collects metric data from the discovered devices within a polling interval. Depending on your snmpcollector version, data polling might be managed externally by poll agent or internally by snmpcollector.

CRCErrors :: 0.0 :: means:-

This function snmpProtectedDiv divides two values inside its bracket and returns the result of the division. If the dividend or divisor is null or 0.0 the return value is 0.0. This function is used to protect the expression from dividing with null or 0. Data Repository can contain null or zero values, such as when a poll fails.

CRCErrors is calculated based on parameters (dot3StatsAlignmentErrors, dot3StatsFCSErrors) 

The formula used to calculate CRCErrors:

<Expression destAttr="CRCErrors">dot3StatsAlignmentErrors+dot3StatsFCSErrors</Expression>

Here the delta time = polling interval.

Based on <NeedsDelta>true</NeedsDelta> in two attribute <Attribute

name="dot3StatsAlignmentErrors" type="Long"> <IsKey>false</IsKey> <NeedsDelta>true</NeedsDelta> <Source>1.3.6.1.2.1.10.7.2.1.2</Source> </Attribute> <Attribute name="dot3StatsFCSErrors" type="Long"> <IsKey>false</IsKey> <NeedsDelta>true</NeedsDelta> <Source>1.3.6.1.2.1.10.7.2.1.3</Source> </Attribute> The

calculation = (current value - previous value) / deltaTime

Note:-

Crcerror = crcerrorIn + crcerrorOut. Crcerror is total error packets. crcerrorin is just packets error in.

calculation of other device, It depend on the Vendor Cert that device using. Their are many ways to calculate CRC error and crc error in.

Additional Information

snmpcollector Polling Intervals

https://techdocs.broadcom.com/us/en/ca-enterprise-software/it-operations-management/ca-unified-infrastructure-management-probes/GA/alphabetical-probe-articles/snmpcollector-snmp-data-monitoring/snmpcollector-theory-of-operations.html