QoS design question

[walfred]

How does cisco define "congestion" with respect to its QoS mechanism. What I mean by that, is if I implement CBWFQ on a specific link (say Frame Relay), at what point does the QoS mechanism go into effect on that link at 30% congestion, 50% congestion....100% congestion. At what value of link utilization.

[Brandon Buffin]

Strictly speaking, there is congestion on the link when the number of packets exceeds the length of the TX Ring/Hardware Queue. The Hardware Queue length is configurable and the default varies by platform. When this threshhold is reached, the queuing mechanism (CBWFQ in this case) takes affect.

Hope this helps.

Brandon