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Cisco7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter42 Configuring PFC QoS
Understanding How PFC QoS Works
Flowchart of Ingress LAN Port PFC QoS Features

Figure 42-5 shows how traffic flows through the ingress LAN port PFC QoS features.

Figure 42-5 Ingress LAN Port PFCQoS Features
Note Ingress CoS mutation is supported only on 802.1Q tunnel ports.
Release 12.2(18)SXF5 and later releases support the ignore port trust feature.
DSCP-based queue mapping is supported only on WS-X6708-10GE ports.
154684
Yes
Frame
enters
switch
Port set to
untrusted?
ISL or
802.1Q?
No No
No
Port set to
trust-ipprec?
Port set to
trust-dscp?
Ingress
CoS
Mutation?
IP
traffic with
recognizable
ToS byte?
IP
traffic with
recognizable
ToS byte?
Ignore
port trust
enabled?
DSCP-based
queue mapping
enabled?
No
No
No
No
No
No
Port is set to
trust-cos
To
PFC
Apply
port
CoS
Apply
port
CoS
Yes Yes Yes
Yes
Yes
Mutate
CoS
Ingress queues and
drop thresholds
DSCP-to-queue
map
CoS-to-queue
map
Yes
Yes