Override of global QoS settings

After you apply a QoS policy to an interface, the classifier-based settings configured by QoS actions in the policy override any 802.1p CoS or DSCP codepoint values that were globally-configured on the switch to mark packets using the QoS commands.

If you use a classifier-based QoS configuration along with globally-configured QoS commands, the order of precedence in which 802.1p priority, IP precedence, and DSCP settings mark selected packets is as follows, from highest (1) to lowest (9):

Order of precedence for classifier-based QoS over global QoS

Precedence order

QoS feature

1

Classifier-based port-specific policy

2

Classifier-based VLAN-specific policy

3

Globally-configured TCP/UDP priority

4

Globally-configured IP-device priority

5

Globally-configured IP Type-of-Service priority

6

Globally-configured Layer 3-Protocol priority

7

Globally-configured VLAN-ID priority

8

Globally-configured Source-Port priority

9

802.1p CoS in Layer 2 VLAN header1

1

In a tagged VLAN environment, the incoming 802.1p priority is used as the default QoS classifier to determine how a packet is handled if no global or classifier-based QoS match criterion with a higher precedence matches.