The Marine Corps Mobilization Command (MOBCOM) is a Major Subordinate Command (MSC) of Marine Forces Reserve and provides support for all Individual Ready Reserve (IRR), Individual Mobilization Augmentee (IMA) and Mobilized Training Unit Marine reservists. MOBCOM exercises centralized command and administration of the IRR. The IRR is composed of former Active Duty or Reserve component personnel who have not completed their Military Service Obligation (MSO) or have completed their MSO and are in the Ready Reserve by voluntary agreement.