esaProbeHistoryY1731R2PFrames is a 64-bit performance counter, applicable only to Y.1731 probes, counting data frames the destination MEP transmits from the reflector back to the probe, for a completed interval that has already closed and been archived into the rolling history log. This frame count reflects exactly what the MEP is configured to count, namely its priority filter and its VLAN (MA VID) membership, so a technician cross-checking it against a switch port counter needs to remember it may deliberately be a subset of total traffic. For example, comparing this frame count across archived bins before and after a MA VID list change confirms, after the fact, exactly when the new VLAN scope took effect.