41-4
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 41 Configuring QoS
Understanding How QoS Works
Figure 41-2 Ethernet ingress Port Classification, Marking, Scheduling, and Congestion Avoidance
49393
Yes
Frame
enters
switch
Port set to
untrusted?
ISL or
802.1Q?
(tail-drop thresholds)
1q4t port
1p1q4t
(tail-drop thresholds)
100% for CoS 6 and 7
80% for CoS 4 and 5
60% for CoS 2 and 3
50% for CoS 0 and 1
Strict pr iority queue
100% for CoS 5
Standard queue
100% for CoS 6 and 7
80% for CoS 4
60% for CoS 2 and 3
50% for CoS 0 and 1
Apply
port
CoS
No
No
Yes
Port set to
trust-ipprec?
Port set to
trust-dscp?
No
No
Port is set to
trust-cos
To
switching engine
Apply
port
CoS
(Default values
shown)
Ethernet ingress port classification, marking,
scheduling, and congestion avoidance
Yes
Yes
1p1q0t port
(tail-drop thresholds)
Strict priority queue
100% for CoS 5
Standard queue
100% for CoS 0, 1, 2, 3, 4, 6, 7