Priority-flow-control (PFC) buffer and history counters provide information on both present PFC pause conditions and past pause events. These buffer counters (since EOS-4.34.2F) and history counters (since EOS-4.35.0F) are available via OpenConfig in addition to the show commands that have existed in previous versions.

Priority-based flow control (PFC) buffer counters track ingress port buffer usage for each packet priority. This feature displays the high watermark buffer usage over two time intervals: a polling interval (by default 2 seconds) and the encompassing interval since the counters were cleared. The PFC buffer counter watermarks can be used to expose bursty and transient ingress buffer resource usage. High watermark values indicate congestion conditions that could explain packet loss.