Use a different VC for some devices instead of VC natively supported

Products

CA Performance Management - Usage and Administration DX NetOps

Issue/Introduction

In some cases where the wrong VC gets mapped, incorrect statistics result. For example, if a device such as a Cisco FirePower Security Appliance may not be properly or fully certified in a previous version of CAPM. However, it is similar enough to an already certified device that it is discovered but using a VC for some metrics which result in incorrect statistic values such as for the Memory Metric Family (MF). In this case, because the Cisco Enhanced Memory Pool VC is higher in the priority list order, it will be selected instead of the Cisco CPM Memory VC, which is the VC that provides the correct values for the Memory MF for this device:

The VC priority order can be changed, but then this would affect other devices statistics and make them invalid. And Vendor Certifications (VCs) can't be bound to certain collections.

Instead, what can be done is to use the <VCSupportExpression> tag in the Cisco Enhanced Memory Pool to prevent this VC from discovering the device.

Environment

All supported DX NetOps Performance Management releases

Resolution

There are two ways to address this. One is setting up Collection Groups with specific device sets added to them. Create a custom Metric Family (MF) with the required Vendor Certifications (VC) associated. Connect the Collection Group and proper MP.

A less complex solution for the long term is an extension against the target VC(s). It would tell the VC not to allow its use for a given sysObjectID or set of sysObjectID values. It would ignore the VC in favor of one next in line the device supports.

Set the VCP Order back to default. For example here we'll use this order as the default and tell it to not support the 'Cisco Memory' VC in favor of the next one, the 'Cisco Enhanced Memory Pool' VC.
Using a REST client import the following XML against the Cisco Memory VC Extension. See the Create or Extend Vendor Certifications documentation topic for more details. Ensure the correct sysObjectID is set. The below is an example.

<DataModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" namespace="http://im.ca.com/certifications/snmp" xsi:noNamespaceSchemaLocation="SNMPCertificationFacet.xsd">
	<Author>Customer</Author>
	<Version>2.0</Version>
	<FacetType name="CiscoMemMib" descriptorClass="com.ca.im.core.datamodel.certs.CertificationFacetDescriptorImpl">
		<FacetOf namespace="http://im.ca.com/core" name="Item"/>
		<Attribute name="sysObjectID" external="true" type="ObjectID">
			<Documentation/>
			<IsKey>true</IsKey>
			<Source>1.3.6.1.2.1.1.2.0</Source>
		</Attribute>
		<Expressions>
			<ExpressionGroup destCert="{http://im.ca.com/normalizer}NormalizedMemoryInfo" name="CiscoNRMMemDS">
				<VCSupportExpression>sysObjectID.toString() !="1.3.6.1.4.1.9.1.896"</VCSupportExpression>
			</ExpressionGroup>
		</Expressions>
	</FacetType>
</DataModel>

Additional Information

Need to specify more than one sysObjectID value? We'd use a single line containing multiple entries. An example would be the following.

<VCSupportExpression>sysObjectID.toString() !="1.3.6.1.4.1.9.1.896" &amp;&amp; sysObjectID.toString() !="1.3.6.1.4.1.9.1.897" &amp;&amp; sysObjectID.toString() !="1.3.6.1.4.1.9.1.898"</VCSupportExpression>

Need to specify which sysOjbectID values that SHOULD be supported?
- Engineering does not recommend this path. They suggest using the filters to tell the VC which sysObjectID values NOT to support.
- Use || instead of &&. Doing so the same example becomes this.
  - ```
  <VCSupportExpression>sysObjectID.toString() !="1.3.6.1.4.1.9.1.896" || sysObjectID.toString() !="1.3.6.1.4.1.9.1.897" || sysObjectID.toString() !="1.3.6.1.4.1.9.1.898"</VCSupportExpression>
```
The VCSupportExpression tag is described further in the Vendor Certification XML Structure documentation topic.
Complete details about how to create or extend VCs is found in the Create or Extend Vendor Certifications documentation topic.