tmnxOamMcastTrRespSrcMask 1.3.6.1.4.1.6527.3.1.2.11.2.17.1.12

tmnxOamMcastTrRespSrcMask contains the number of 1's in the netmask this router has for the source (i.e. a value of 24 means the netmask is 0xffffff00). If the router is forwarding solely on group state, this field is set to 63 (0x3f).