This counts events where the receive-side PDV jitter buffer filled completely, forcing the device to discard incoming packets it had no room to buffer. Overrun on this pseudowire is the opposite failure mode from Underrun -- packets arriving faster or burstier than the buffer was sized for -- and a climbing count here suggests the buffer depth should be increased or the network path is delivering unexpectedly bursty traffic -- and this specific object covers a closed 15-minute history bin -- a fixed, final count for one completed interval rather than something still changing. For example, over that completed 15-minute bin, this pseudowire might show this counter at 2 -- a concrete count the admin can trend against neighboring bins to judge whether the condition it reflects is worsening.