When set to 'Y.1731 OAM', this switch transmits Y.1731 OAM PDUs as background traffic, and DST is OAM-aware determines the PDU type. In the current version of the software, only one ECE can be tested at a time in this mode. When set to 'Simulated Customer', the software will generate a traffic-pattern per ECE that will hit the ECE, and use the ECE's counters to determine PASS/FAIL criteria.Besides supporting simultaneous test of multiple ECEs, 'Simulated Customer' has the advantage that the tester can see directly from the report if she has configured ECEs wrongly, since the report will show per-ECE counters and fail if an ECE under test is not hit as expected by the traffic pattern.