With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swPimRPSetGroupAddress
Switch Pim RP Set Group Address
1.3.6.1.4.1.171.12.52.3.8.2.1.2
The IP multicast group address which, when combined with pimRPSetGroupMask, gives the group a prefix. This prefix will determine for which entry CRP information is to be displayed, and which entry contains information about the Candidate-RP.
Back to PIM-SM-MIB MIB page.
IPHost Network monitor allows you to monitor swPimRPSetGroupAddress 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.