With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swL2TrunkIndex
Switch L2 Trunk Index
1.3.6.1.4.1.171.11.70.5.2.9.3.1.1
The index of logical port trunk. The trunk group number depend on the existence of unit and module.
Back to DGS3612-L2MGMT-MIB MIB page.
IPHost Network monitor allows you to monitor swL2TrunkIndex 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.