Querying Infosets

When crafting scan rule sets for device role detection, there can be discovery performance benefits to querying information sets (also referred to as infosets). However, for completeness of information, role detection rules that query WMI/SNMP directly are best. This section describes the differences between these two methods within the context of device role and sub role determination.

Important: Building and using a role detection rule that can query an incomplete infoset will affect the accuracy of role determination. For example, it can lead to a 'false negative' for cases when Discovery checks an infoset for a value before it can be fetched by SNMP or WMI.

Tip: When your scan rule checks for a value or field using SNMP/WMI, WhatsUp Gold Discovery associates it with an infoset. So, querying the infoset in subsequent rules (if necessary) rather than duplicating SNMP/WMI calls can be helpful when scanning large scale networks.

Scan rules that apply queries to infosets are different than other queries because:

• Infosets are temporary structures used by discovery.
• Scan rules that query infosets are actually inspecting data cached as part of the current discovery scan (no network call).
• Scan rules that query management objects (WMI/SNMP) make a network call to the device.
• WhatsUp Gold populates infosets as the current discovery progresses, so not all complimentary information are present at intermediary points in the scan. For example, attributes related to child/parent relationships are not guaranteed to be there.

How can I query infosets?

Infosets are internal structures leveraged by WhatsUp Gold that are partially exposed for extending discovery support. You can find the best examples for using infosets by viewing scan rules for system sub roles.

Information Set Scan Rule Defined within Dell Storage Center Sub Role

Example Scan Detection Rules that Use Infosets (Cisco Meraki sub role rule group shown)

Queryable Parts of an Infoset

Infosets leverage a namespace or tree-like structure. You can use scan rules within a role or sub role definition to query the following infoset parts:

• Name. ID, root element of the infoset. Name part of a name/value pair.
• Value. Paired value for ID.
• Infoset Path. Typical paths used for a given infoset name that is in practical use.

The following table outlines parts of infosets exposed for discovery performance optimizations.

Infoset Name	Value Attributes	Infoset Path
cloud	Azure, AWS, CiscoMeraki	/cloud/platform
	LWAP, VirtualMachine, Portal/ LoadBalancer	/cloud/type
netapp-encl-table	Cluster (regular expression)	/netapp-encl-table/entry
netapp-product	NetApp, *Node	/netapp-product/role
smis-agent	NetApp	/smis-agent/entries/entry/cluster-redundancy
	*Array	/smis-agent/role
	root/emc/smis (regular expression)	/smis-agent/entries/entry/name-space
virt-machine	Typically evaluated as a regular expression. For example: '(Windows|Microsoft).*Server.*2012 R2'	/virt-machine/guest-os

See Also Building Rule Sets for Device Detection Device Scan Rules