With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
vsanMembershipSummaryEntry
vsan Membership Summary Entry
1.3.6.1.4.1.9.9.282.1.2.8.1
A row in the vsanMembershipSummaryTable. Each row identifies one interface such that the identified interface is one of the potentially many interfaces which are members of a particular VSAN.
Back to CISCO-VSAN-MIB MIB page.
IPHost Network monitor allows you to monitor vsanMembershipSummaryEntry 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.