Configuring Auto-Qos; Generated Auto-Qos Configuration - Cisco Catalyst 2950 Software Configuration Manual

Configuring Auto-QoS

Configuring Auto-QoS
This feature is available only if your switch is running the EI.
Note
You can use the auto-QoS feature to simplify the deployment of existing QoS features. Auto-QoS makes
assumptions about the network design, and as a result, the switch can prioritize different traffic flows
and appropriately use the egress queues instead of using the default QoS behavior (the switch offers
best-effort service to each packet regardless of the packet contents or size and sends it from a single
queue).
When you enable auto-QoS, it automatically classifies traffic based on the traffic type and ingress packet
label. The switch uses the resulting classification to choose the appropriate egress queue.
You use auto-QoS commands to identify ports connected to Cisco IP Phones and to devices running the
Cisco SoftPhone application. You also use the commands to identify ports that receive trusted traffic
through an uplink. Auto-QoS then performs these functions:
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•
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These sections describe how to configure auto-QoS on your switch:
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Generated Auto-QoS Configuration

When auto-QoS is enabled, it uses the ingress packet label to classify traffic and to configure the egress
queues as described in
Table 29-2 Traffic Types, Packet Labels, and Egress Queues
1
VoIP Data
Traffic
DSCP 46
CoS 5
CoS-to-Queue 5
Map
Egress Queue 1% WRR
(queue 4)
1. VoIP = voice over IP
2. BPDU = bridge protocol data unit
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
29-10
Detects the presence or absence of IP phones
Configures QoS classification
Configures egress queues
Generated Auto-QoS Configuration, page 29-10
Effects of Auto-QoS on the Configuration, page 29-12
Configuration Guidelines, page 29-13
Upgrading from a Previous Software Release, page 29-13
Enabling Auto-QoS for VoIP, page 29-14
Table 29-2.
VoIP Control Routing Protocol
Traffic Traffic
24, 26 48
3 6
3, 6, 7
70% WRR (queue 3)
2
STP BPDU Real-Time
Traffic Video Traffic
56 34
7 4
4
20% WRR
(queue 2)
Chapter 29 Configuring QoS
All Other Traffic
–
2 0, 1
20% WRR 10% WRR
(queue 2) (queue 1)
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