This read-write enumerated value controls the row-management action performed on a VP trunk range entry - enable to add a new range mapping, modify to change an existing one's attributes, or disable to delete the row entirely. Admins use this as the "commit" action when provisioning or removing VPI-to-trunk range mappings, since simply setting the min/max VPI values elsewhere doesn't take effect until this operation type is applied. For example, after setting imatmTrkMinVp and imatmTrkMaxVp for a new range, the admin sets imatmTrkOpType to enable to actually create that row in the table.