esaProbeSOAMPktSize is a read-write Integer32 (0 or 64 to 9612 bytes) specifying the packet size used by SLM-SLR probes for the first Class of Service, returning 0 once multiple COS levels are active since the setting no longer applies to a single value. An administrator sizes this to match the packet sizes actually carried by the customer's real traffic, so the SLA test is representative rather than testing only small control-sized packets. For example, setting this near the path's MTU exposes fragmentation or large-packet queuing delay that a probe left at a small default packet size would never reveal.