Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
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Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
auto qos voip
auto qos voip
Use the auto qos voip interface configuration command to automatically configure 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 | cisco-softphone | trust}
no auto qos voip
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 class of service (CoS)
packet labels and to configure the egress queues as summarized in
Table 2-1.
Table 2-2 lists the auto-QoS configuration for the egress queues.
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
telephone is detected.
cisco-softphone Identify this port as connected to a device running the Cisco SoftPhone, and
automatically configure QoS for VoIP.
trust Identify this interface as connected to a trusted switch or router, and automatically
configure QoS for VoIP. The QoS labels of incoming packets are trusted.
Ta b l e 2-1 Traffic Types, Packet Labels, and Egress Queues
VoIP Data
Traffic
VoIP Control
Traffic
Routing Protocol
Traffic
STP
1
BPDU
2
Traffic
1. STP = Spanning Tree Protocol
2. BPDU = bridge protocol data unit
Real-Time
Video Traffic All Other Traffic
DSCP
3
3. DSCP = Differentiated Services Code Point
46 24, 26 48 56 34 —
—
CoS 5 3 6 7 4
CoS-to-Queue
Map
5 3, 6, 7 4 2 0, 1
Egress Queue Expedite
(queue 4)
70% WRR
4
(queue 3)
4. WRR = weighted round robin
20% WRR
(queue 2)
20% WRR
(queue 2)
10% WRR
(queue 1)