Quality of Service (QoS): Managing Bandwidth More Effectively  
Using QoS Classifiers To Configure QoS for Outbound Traffic 
Syntax:  vlan < vid > qos dscp < codepoint > 
Assigns a DSCP policy to packets carrying the specified IP 
address, and overwrites the DSCP in these packets with the 
assigned < 
codepoint > value. This policy includes an 802.1p 
priority and determines the packet’s queue in the outbound 
port to which it is sent. If the packet leaves the switch on a 
tagged port, it carries the 802.1p priority with it to the next 
downstream device. (Default: 
No-override) 
no vlan < vid > qos 
Removes QoS classifier for the specified VLAN. 
show qos device-priority 
Displays a listing of all QoS VLAN-ID classifiers currently 
in the running-config file. 
For example, suppose you wanted to assign this set of priorities: 
VLAN-ID  DSCP  Priority 
40  000111  7 
30  000101  5 
20  000010  1 
1  000010  1 
1.   Determine whether the DSCPs already have priority assignments, which 
could indicate use by existing applications. This is not a problem as long 
as the configured priorities are acceptable for all applications using the 
same DSCP. (Refer to the “Note On Changing a Priority Setting” on page 
6-61. Also, a DSCP must have a priority configured before you can assign 
any QoS classifiers to use it.) 
The DSCPs for this 
example have not yet 
been assigned an 
802.1p priority level. 
Figure 6-25.  Display the Current Configuration in the DSCP Policy Table 
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