How do I discover Cisco VLans groups and add them into groups

Document ID : KB000023256
Last Modified Date : 14/02/2018
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Question: How do I discover Cisco VLans groups and add them into groups

Answer: The NH_DISCOVER_CISCO_VLAN_GROUPS environment variable specifies whether eHealth should discover Cisco Catalyst switches and automatically add them as an eHealth group.

The default value is off

The valid values are:
on - which enables the discovery of Cisco Virtual LANs (VLANs) and automatically adds Cisco Catalyst switch ports and trunks to groups.
off - disables the discovery of Cisco VLANs and group creation.

eHealth assigns trunks to a group named CISCO-VLAN-ALL-TRUNKS. If a port belongs to a named VLAN, eHealth adds the port to a group called CISCO-VLAN-vlanName. For example, for a VLAN called "North," eHealth creates a group named CISCO-VLAN-North. If a port belongs to an unnamed VLAN, eHealth determines whether the VLAN is configured on a local switch. If so, eHealth assigns the port to a group named CISCO-sysname-VLAN-vlanIndex, where sysname is the name of the local switch, and vlanIndex is the index of the VLAN. If the port belongs to an unnamed VLAN that is configured across multiple switches, eHealth assigns the port to a group named CISCO-VLAN-vlanIndex. If these groups do not exist, eHealth creates them automatically.


For information on setting eHealth environment variables, refer to the following:


How to Set or Change eHealth Environment Variables-NT


How to Set or Change eHealth Environment Variables-Unix


Related Issues/Questions:
Monitoring VLAN traffic
How to set the environment variable NH_DISCOVER_CISCO_VLAN_GROUPS
How to discover VLAN groups on Cisco devices

Additional Information:
The followng OIDS must be present and populated for the discovery process to create the groups accordingly:

VLAN ports span across multiple switches. In order to get traffic statistics on a particular VLAN that spans across multiple switches, each port needs to be discovered, then placed into a group for that VLAN. Reports can then be run on that group to get traffic for the VLAN in question.
There are some devices (switches) that report on statistics on mib entries for VLANs. However, those entries in the MIB are only for the portion of traffic seen by that particular switch. Any traffic on the VLAN that uses a different switch will not be reported for this device.
What this means is that licensing must be purchased for all the interfaces that make up their VLANs, then discover the interfaces and group them according to VLAN membership in order to see aggregate performance for the VLAN. Autogrouping is current available for Cisco Catalyst Switches and will be available for Foundry switches starting in 5.0.2 D02 by setting the environment variable NH_DISCOVER_CISCO_VLAN_GROUPS=on

(Legacy KB ID CNC TS5681 )