Bad optics or a bad cable corrupt a steady share of the packets that pass through that path.
Why Bit errors from bad optics or cables → Effect The equipment silently drops corrupted packets → On screen Only some servers or players using that path teleport or rubber-band from steady packet loss
Monitor and alert on port error (CRC) counters, replace parts such as optics and cables, take the problem link out and route around it until it’s replaced.
On the graph
Outliers only · CRC errors per port, loss rate per server/path
Where to look
Check the CRC counters on both ends of the link. On switches, the port’s FCS errors (dot3StatsFCSErrors) and input errors (ifInErrors); on servers, crc under RX errors in ip -s -s link (kernel stat rx_crc_errors)
Confirmed if
CRC errors on one port keep rising regardless of traffic volume or time of day, and only servers and players passing through that port see loss
Ruled out if
No CRC errors and only output drops rising: congestion (“Switch microbursts,” “Data center link saturation”)