With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
vlanTrunkMappingTable
vlan Trunk Mapping Table
1.3.6.1.4.1.9.5.1.9.8
VLAN to VLAN associations. The maximum number of active entries is determined by vlanTrunkMappingMax. VLAN above 1k can not be created if the value of corresponding instance of vlanTrunkMappingType is dot1qToisl(2).
Back to CISCO-STACK-MIB MIB page.
IPHost Network monitor allows you to monitor vlanTrunkMappingTable on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco optical switches right now.