This object specifies the service protected VLANs of ERP instance in a string of octets containing one bit per VLAN for VLANs 2049 to 4094. If the bit is set to '1', then the VLAN is configured to be protected by the Ethernet ring protection mechanism.
Sources for this description
D-Link official switch MIBsD-Link MIB copies (LibreNMS/Observium Community)