Cisco Catalyst 3550 Command Reference Manual page 41

Chapter 2 Cisco IOS Commands
Table 2-2
Table 2-2
Egress Queue
Expedite
80% WRR
20% WRR
Command Modes Interface configuration
Command History Release
12.1(12c)EA1
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.
Use the cisco-phone keyword on ports at the edge of the network that are connected to Cisco IP phones.
The switch detects the telephone through the Cisco Discovery Protocol (CDP) and trusts the QoS labels
in packets received from the telephone.
Use the trust keyword on ports connected to the interior of the network. Because it is assumed that traffic
has already been classified by other edge devices, the QoS labels in these packets are trusted.
When you enable the auto-QoS feature on the first interface, these automatic actions occur:
•
•
•
You can enable auto-QoS on static, dynamic-access, voice VLAN access, and trunk ports.
To display the QoS configuration that is automatically generated when auto-QoS is enabled, enable
debugging before you enable auto-QoS. Use the debug autoqos privileged EXEC command to enable
auto-QoS debugging.
To disable auto-QoS on an interface, use the no auto qos voip interface configuration command. When
you enter this command, the switch enables standard QoS and changes the auto-QoS settings to the
standard-QoS default settings for that interface.
78-11195-09
lists the auto-QoS configuration for the egress queues.
Auto-QoS Configuration for the Egress Queues
Queue
Number
4
3
1
Modification
This command was first introduced.
QoS is globally enabled (mls qos global configuration command).
When you enter the auto qos voip cisco-phone interface configuration command, the trusted
boundary feature is enabled. It uses the Cisco Discovery Protocol (CDP) to detect the presence or
absence of a Cisco IP phone. When a Cisco IP phone is detected, the ingress classification on the
interface is set to trust the QoS label received in the packet. When a Cisco IP phone is absent, the
ingress classification is set to not trust the QoS label in the packet. The egress queues on the
interface are also reconfigured (see
When you enter the auto qos voip trust interface configuration command, the ingress classification
on the interface is set to trust the QoS label received in the packet, and the egress queues on the
interface are reconfigured (see
CoS-to-Queue Queue
Map Weight
5 –
3, 6, 7 80%
0, 1, 2, 4 20%
Table 2-2).
Table 2-2).
Catalyst 3550 Multilayer Switch Command Reference
Queue Size for Queue Size (in
Gigabit-Capable packets) for 10/100
Ports Ethernet Ports
– 26
20% 65
80% 170
auto qos voip
2-15