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Manage devices with poor SNMP get-bulk responses in DX NetOps

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Article ID: 238067

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Updated On:

Products

CA Performance Management - Usage and Administration DX NetOps

Issue/Introduction

We have devices that do not perform well when SNMP get-bulk queries are utilized during Metric Family MIB discovery.

When these methods are used they can result in response errors from the device.

As a result we can see problems discovering devices and component items or we can see problems during polling.

Cause

Poorly performing devices in the network

Environment

DX NetOps Performance Management Data Aggregator releases 21.2.8 and newer.

Resolution

As seen in the 21.2.8 Fixed Issues list a new feature has been added that can be used to manage this behavior.

  • Symptom: Many metric family components were not discovered on LANCOM devices due to bulk get returning success but varbinds not being in lexicographical order. SNMP engine could not process the varbinds correctly.
  • Resolution: The SysOIDForSnmpGetNext configuration attribute has been introduced on the data aggregator /rest/discoverydefaultconfig endpoint. This attribute denotes device sysObjectIDs that will use get-next instead of bulk get method for MIB table reads during metric family discovery. After making the change, try and discover the components by running update metric family discovery.
  • (21.2.8, DE526622, 32994744)

To implement this configuration for given devices using their sysOjbectID we'd issue a PUT against the DA URL:

<scheme>//<DA_Host>:<Port>/rest/discoverydefaultconfig/<ID>

To determine the <ID> value run a GET against this URL.

<scheme>//<DA_Host>:<Port>/rest/discoverydefaultconfig

The URL Body should contain the following. One SysOIDForSnmpGetNext entry per line with one sysObjectID value per device per line. Can be a single entry or multiple.

<DiscoveryDefaultConfig version="1.0.0">
  <SysOIDForSnmpGetNextList>
	<SysOIDForSnmpGetNext>sysObjectID_1</SysOIDForSnmpGetNext>
	<SysOIDForSnmpGetNext>sysObjectID_2</SysOIDForSnmpGetNext>
	<SysOIDForSnmpGetNext>sysObjectID_3</SysOIDForSnmpGetNext>
  </SysOIDForSnmpGetNextList>
</DiscoveryDefaultConfig>

A sample body configuration using two sysObjectID values is:

<DiscoveryDefaultConfig version="1.0.0">
  <SysOIDForSnmpGetNextList>
	<SysOIDForSnmpGetNext>1.3.6.1.4.1.2356.11.8.623.1</SysOIDForSnmpGetNext>
	<SysOIDForSnmpGetNext>1.3.6.1.4.1.2356.11.8.622</SysOIDForSnmpGetNext>
  </SysOIDForSnmpGetNextList>
</DiscoveryDefaultConfig>