This value specifies and reports the operational state of a two-way Synthetic Loss Measurement (SLM) test: setting it to enabled(1) starts the test (rejecting further changes to other two-way SLM objects while running), setting it to disabled(2) aborts it, and it automatically reverts to disabled(2) once the test completes. An admin sets this to start or stop an on-demand loss-measurement test between two MEPs, used to quantify frame loss rather than just connectivity or delay. Because other two-way SLM objects can't be changed while a test is enabled(1), an admin configures the target MAC, priority, interval, and other test parameters before setting this to start the test.