With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
vsanWwnListNumber
vsan Wwn List Number
1.3.6.1.4.1.9.9.282.1.2.2
The number of WWNs configured both for static and dynamic membership purposes on this device. This is number of rows in the vsanWwnListTable.
Back to CISCO-VSAN-MIB MIB page.
IPHost Network monitor allows you to monitor vsanWwnListNumber on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.