Tag :: PFC

This document describes the PFC (priority-based flow control) history counters that are available to debug network oversubscription issues. These counters track statistics on the switch that is sending network traffic at a rate that is more than what its peer can handle.

DCS 7050X/X2/X3 series. DCS 7060X/X2/X3 series. In previous releases, PFC Watchdog supported only queues

Priority Flow Control is a link-layer flow control mechanism which may be used by an overwhelmed network node to ask its transmitters to stop transmission for a specified period of time. It does so by using special frames known as PFC frames, thus, relieving congestion at the receiver node. With respect to this behavior, PFC is very similar to Link Layer Flow Control ( LLFC ), however, unlike LLFC, PFC allows the overwhelmed node to specify which 802.1Q Class of Service ( CoS ) it wants to stop receiving traffic for. Thus, allowing differentiated treatment of traffic based on CoS.

Priority Flow Control (PFC) Watchdog feature monitors interfaces for priority flow control Pause storm. If such

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.