With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swL2TrunkActivePorts
Switch L2 Trunk Active Ports
1.3.6.1.4.1.171.11.70.5.2.9.3.1.8
The object indicates the active ports of the port trunk entry.
Back to DGS3612-L2MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor swL2TrunkActivePorts 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 switches right now.