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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 31 Configuring PFC QoS
Understanding How PFC QoS Works
Figure 31-7 Egress WAN Port Marking
Figure 31-8 Egress LAN Port Scheduling, Congestion Avoidance, and Marking
Transmit
OSM traffic
68834
IP traffic
from PFC?
Write ToS
byte into
packet
No
Yes
OSM switching module marking
From PFC2 or
MSFC2
OSM
QoS
Features
68002
Write CoS
into
frame
ISL or
802.1Q?
IP traffic
from PFC?
Write ToS
byte into
packet
DSCP
rewrite
enabled?
No No
No
Yes Yes
Yes
Ethernet egress port scheduling, congestion avoidance, and marking
Transmit
frame
From switching
engine or MSFC
Drop thresholds
PFC3
only