Cisco Catalyst 3550

2-21
Catalyst 3550 Multilayer Switch Command Reference
OL-8566-02
Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
auto qos voip
Command Modes Interface configuration
Command History
Usage Guidelines Use this command to configure the QoS appropriate for VoIP traffic within the QoS domain. The QoS
domain includes the switch, the interior of the network, and the edge devices that can classify incoming
traffic for QoS.
In releases earlier than Cisco IOS Release 12.1(20)EA2, auto-QoS configures the switch only for VoIP
with Cisco IP Phones on switch ports.
In Cisco IOS Release 12.1(20)EA2 or later, auto-QoS configures the switch for VoIP with Cisco IP
Phones on switch and routed ports and for VoIP with devices running the Cisco SoftPhone application.
These releases support only Cisco IP SoftPhone Version 1.3(3) or later. Connected devices must use
Cisco Call Manager Version 4 or later.
To take advantage of the auto-QoS defaults, you should enable auto-QoS before you configure other QoS
commands. You can fine-tune the auto-QoS configuration after you enable auto-QoS.
Note The switch applies the auto-QoS-generated commands as if the commands were entered from the
command-line interface (CLI). An existing user configuration can cause the application of the generated
commands to fail or to be overridden by the generated commands. These actions occur without warning.
If all the generated commands are successfully applied, any user-entered configuration that was not
overridden remains in the running configuration. Any user-entered configuration that was overridden
can be retrieved by reloading the switch without saving the current configuration to memory. If the
generated commands fail to be applied, the previous running configuration is restored.
If this is the first port on which you have enabled auto-QoS, the auto-QoS-generated global
configuration commands are executed followed by the interface configuration commands. If you enable
auto-QoS on another port, only the auto-QoS-generated interface configuration commands for that port
are executed.
When you enable the auto-QoS feature on the first interface, these automatic actions occur:
Ta b l e 2-2 Auto-QoS Configuration for the Egress Queues
Egress Queue
Queue
Number
CoS-to-Queue
Map
Queue
Weight
Queue Size for
Gigabit-Capable
Ports
Queue Size (in
packets) for 10/100
Ethernet Ports
Expedite 4 5 – 10 percent 34 (10 percent)
70% WRR 3 3, 6, 7 70 percent 15 percent 51 (15 percent)
20% WRR 2 2, 4 20 percent 25 percent 82 (25 percent)
10% WRR 1 0, 1 10 percent 50 percent 170 (50 percent)
Release Modification
12.1(12c)EA1 This command was introduced.
12.1(20)EA2 The cisco-softphone keyword was added, and the generated auto-QoS
configuration changed.