esaProbeStatsMaxRoundTripDelay is an unsigned 32-bit value that reports the highest recorded round-trip delay of the test packets, in microseconds, with the reflector's own processing time excluded, for the interval that is still being actively collected (the live bin). Round-trip delay is the core proof-of-performance number for an Etherjack SLA test because it reflects everything affecting the circuit in both directions combined, so a technician watches it to confirm the customer's contracted latency bound is being met. For example, a single live bin where this worst-case round-trip delay balloons while the rest of the interval looks ordinary tells the technician a brief congestion event hit the circuit sometime during that interval.