Changing Advanced SPM Settings

Switch Port Management provides for a set period of days after an SPM port is free and unused before it is specifically defined as Available. When a port is first disconnected from all other devices, it is in a Down link state, and appears in the Free category. After a certain time period elapses (the duration of which is based on the business policies of the IT department), the port is counted against the Available category and removed from the Free category, because its link state has been down for longer than the specified time period.

For Switch Port Management, the default transition time between an SPM port's Free status and its change to Available is 14 days.

The ARP Cache Refresh Period defines the time period between ARP refreshes by NetMRI across all switch ports. Before any other switchport polling operations take place (including device group or global polling operations initiated by the NetMRI user), another ARP refresh is carried out by the appliance regardless of the time interval. To modify advanced SPM settings, perform the following:

1. Click the Settings icon > General Settings > Advanced Settings.

2. Under the Switch Port Management category > Free to Available Ports option, click Edit to change the amount of time, in days, a port must remain Free before it becomes administratively Available for new connectivity.

3. Under the Switch Port Management category > ARP Cache Refresh Period option, click Edit to change the time in seconds between ARP refreshes on switch ports managed by the appliance. The default is 300 seconds, because switch forwarding tables are frequently purged from LAN switching devices. The default on Cisco switches is five minutes/300 seconds. NetMRI primarily uses ARP Cache refreshes to improve the accuracy of end-device discovery. Without this feature, some endpoints may not be discovered and cataloged.

4. The ARP Cache Refresh Ignore Discovery Ranges Advanced Setting helps to optimize the discovery of end hosts by disabling pinging of any devices outside of specified discovery ranges. By default, this feature is set to False, which means that devices outside the configured discovery ranges may be pinged by NetMRI. Set this value to True to restrict pinging to end hosts within defined IP ranges.

5. Switch Port Management can use the ARP Cache Refresh Device History to allow pinging of devices listed in older tables compiled from previous polling days, prior to the most recently compiled End Host data tables. The default value is 14 days and the minimum value is one day.

6. Click OK when finished.

For the Free to Available Ports value, the new setting is reflected as the hyperlink in the Available Ports and Available Ports % counters in the Capacity Summary – Ports panel under Switch Port Management.