Specifications

2-8
Catalyst 2950 and Catalyst 2955 Switch Command Reference
78-15304-01
Chapter 2 Cisco IOS Commands
auto qos voip
auto qos voip
Use the auto qos voip interface configuration command to configure automatic quality of service
(auto-QoS) for voice over IP (VoIP) within a QoS domain. Use the no form of this command to change
the auto-QoS configuration settings to the standard-QoS defaults.
auto qos voip {cisco-phone | trust}
no auto qos voip
This command is available only if your switch is running the enhanced software image (EI).
Syntax Description
Defaults Auto-QoS is disabled on all interfaces.
When auto-QoS is enabled, it uses the ingress packet label to categorize traffic and to configure the
egress queues as summarized in Table 2-1.
cisco-phone Identify this interface as connected to a Cisco IP phone, and automatically
configure QoS for VoIP. The QoS labels of incoming packets are trusted
only when the phone is detected.
trust Identify this interface as connected to a trusted switch or router. The QoS
labels of incoming packets are trusted.
Table 2-1 Traffic Types, Ingress Packet Labels, Assigned Packet Labels, and Egress Queues
VoIP Data
Traffic Only
From Cisco IP
Phones
VoIP Control
Traffic Only
From Cisco IP
Phones
Routing Protocol
Traffic
STP
1
BPDU
2
Traffic
1. STP = Spanning Tree Protocol
2. BPDU = bridge protocol data unit
All Other
Traffic
Ingress DSCP
3
3. DSCP = Differentiated Services Code Point
46 26 –––
Ingress CoS 5 3 6 7 –
Assigned DSCP 46 26 48 56 0
Assigned CoS 5 3 6 7 0
CoS-to-Queue
Map
5 3, 6, 7 0, 1, 2, 4
Egress Queue Expedite
queue
80% WRR
4
4. WRR = weighted round robin
20% WRR