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Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 7 Marking Traffic
Class of Service Marking
QinQ Class of Service Marking
For EXP-to-CoS mapping in QinQ configurations, the parallel express forwarding (PXF) engine marks
both the inner and outer CoS bits.
For CoS-to-EXP mapping in QinQ configurations, the PXF engine looks at the CoS bits in the outer
dot1q header to determine how to mark the EXP bits.
set cos Command
To set the Layer 2 class of service (CoS) value of an outgoing packet, use the
set cos
command in
policy-map class configuration mode. To remove a specific CoS value setting, use the
no
form of this
command. By default, this command is disabled.
set cos
cos-value
no
set cos
cos-value
Syntax Description
set cos Command History
Usage Guidelines for the set cos Command
The
set cos
command allows switches and routers to interoperate. By configuring the router to match
packets based on the CoS value (using the
match cos
command) and to set CoS values, you can configure
Layer 2 to Layer 3 mapping. If a packet that needs to be marked to differentiate user-defined QoS
services is leaving a router and entering a switch, the router can set the CoS value of the packet because
the switch can process the Layer 2 header.
Use the
set cos
command only in service policies that are attached in the output direction of an interface;
packets entering an interface cannot be set with a CoS value. You can configure a CoS value on an
Ethernet interface that is configured for 802.1Q or on a virtual access interface that is using an 802.1Q
interface.
cos-value
Is a specific IEEE 802.1Q CoS value from 0 to 7.
Cisco IOS Release
Description
Release 12.0(16)BX
This command was introduced on the PRE2 only.
Release 12.2(28)SB
This command was integrated in Cisco IOS Release 12.2(28)SB for the
PRE2.
Release 12.2(31)SB2
This command was integrated in Cisco IOS Release 12.2(31)SB2 for the
PRE3.
Release 12.2(33)SB
This command was introduced on the PRE4.