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Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
Chapter 36 Configuring QoS
Understanding QoS
Figure 36-4
shows the policing and marking process.
Figure 36-4
Policing and Marking Flowchart on Physical Ports
Mapping Tables
During QoS processing, the switch represents the priority of all traffic (including non-IP traffic) with an
QoS label based on the DSCP or CoS value from the classification stage:
•
During classification, QoS uses configurable mapping tables to derive a corresponding DSCP or
CoS value from a received CoS, DSCP, or IP precedence value. These maps include the
CoS-to-DSCP map and the IP-precedence-to-DSCP map. You configure these maps by using the
mls
qos map cos-dscp
and the
mls qos map ip-prec-dscp
global configuration commands.
On an ingress port configured in the DSCP-trusted state, if the DSCP values are different between
the QoS domains, you can apply the configurable DSCP-to-DSCP-mutation map to the port that is
on the boundary between the two QoS domains. You configure this map by using the
mls qos map
dscp-mutation
global configuration command.
•
During policing, QoS can assign another DSCP value to an IP or a non-IP packet (if the packet is
out of profile and the policer specifies a marked-down value). This configurable map is called the
policed-DSCP map. You configure this map by using the
mls qos map policed-dscp
global
configuration command.
868
3
5
Ye
s
Ye
s
No
No
P
ass
through
Drop
M
a
rk
Get the cl
as
ific
a
tion
re
s
ult for the p
a
cket.
I
s
a
policer configured
for thi
s
p
a
cket?
Check if the p
a
cket i
s
in
profile by querying the policer.
Check out-of-profile
a
ction
configured for thi
s
policer.
Drop p
a
cket.
Modify D
S
CP
a
ccording to the
policed-D
S
CP m
a
p. Gener
a
te
a
new Qo
S
l
a
bel.
S
t
a
rt
Done
