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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 31 Configuring PFC QoS
Understanding How PFC QoS Works
Figure 31-3 Ingress LAN Port Layer 2 PFC QoS Features
68001
Yes
Frame
enters
switch
Port set to
untrusted?
ISL or
802.1Q?
Drop thresholds
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
Ethernet ingress port classification, marking,
scheduling, and congestion avoidance
Yes
Yes