![Cisco 2948G - Catalyst Switch Configuration Manual Download Page 280](http://html.mh-extra.com/html/cisco/2948g-catalyst-switch/2948g-catalyst-switch_configuration-manual_67462280.webp)
14-4
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
—
Release 8.1
78-15486-01
Chapter 14 Configuring QoS
Software Requirements
Software Requirements
QoS requires supervisor engine software release 5.2 or later releases. Use the show port capabilities
command to determine the specific QoS support for a module.
QoS Default Configuration
Table 14-1
shows the QoS default configuration.
Configuring QoS on the Switch
These sections describe how to configure QoS:
•
Enabling QoS Globally, page 14-5
•
Configuring the Default CoS Value for the Switch, page 14-5
•
Reverting to the Default Switch CoS Value, page 14-5
•
Mapping CoS Values to Transmit Queues and Drop Thresholds, page 14-6
•
Reverting to the Default CoS-to-Transmit Queue and Drop Threshold Mapping, page 14-6
•
Displaying QoS Information, page 14-7
•
Reverting to QoS Defaults, page 14-7
•
Disabling QoS, page 14-7
Note
Because entering some QoS commands disables and then reenables ports (which can cause spanning tree
topology changes), enter QoS commands only when necessary.
Table 14-1 QoS Default Configuration
Feature
Default Value
QoS global enable state
Disabled
Switch CoS value
0
Transmit queue drop threshold percentages
•
Threshold 1:100%
1
1.
Not user-configurable
CoS value-to-drop threshold mapping
•
Transmit queue drop threshold 1: CoS 0–7
1.
CoS value-to-transmit queue mapping
•
Transmit queue 1: CoS 0–7
•
Transmit queue 2: None configured