With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swDoubleVlanGlobalState
Switch Double Vlan Global State
1.3.6.1.4.1.171.12.28.1.1
This object enable\disable the double vlan status of the device.
Back to Double-VLAN-MIB MIB page.
IPHost Network monitor allows you to monitor swDoubleVlanGlobalState on D-Link device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring D-Link access points right now.