Configuring Auto-Qos - Cisco WS-CBS3032-DEL Software Configuration Manual

Chapter 37 Configuring QoS
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Configuring Auto-QoS

You can use the auto-QoS feature to simplify the deployment of QoS features. Auto-QoS determines the
network design and enables QoS configurations so that the switch can prioritize different traffic flows.
It uses the ingress and egress queues instead of using the default (disabled) 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 classification results to choose the appropriate egress queue.
Beginning with Cisco IOS Release 12.2(52)SE, auto-QoS supports IPv4 and IPv6 traffic when you
configure the dual IPv4 and IPv6 SDM template with the sdm prefer dual ipv4-and-ipv6 global
configuration command.
You use auto-QoS commands to identify ports connected to these Cisco devices:
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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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These sections contain this configuration information:
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OL-13270-06
During policing, IP and non-IP packets can have another DSCP assigned to them (if they are out of
profile and the policer specifies a markdown DSCP). Once again, the DSCP in the packet is not
modified, but an indication of the marked-down value is carried along. For IP packets, the packet
modification occurs at a later stage; for non-IP packets the DSCP is converted to CoS and used for
queueing and scheduling decisions.
Depending on the QoS label assigned to a frame and the mutation chosen, the DSCP and CoS values
of the frame are rewritten. If you do not configure the mutation map and if you configure the port to
trust the DSCP of the incoming frame, the DSCP value in the frame is not changed, but the CoS is
rewritten according to the DSCP-to-CoS map. If you configure the port to trust the CoS of the
incoming frame and it is an IP packet, the CoS value in the frame is not changed, but the DSCP might
be changed according to the CoS-to-DSCP map.
The input mutation causes the DSCP to be rewritten depending on the new value of DSCP chosen.
The set action in a policy map also causes the DSCP to be rewritten.
Cisco IP Phones
Devices running the Cisco SoftPhone application
Cisco TelePresence
Cisco IP Camera
Detects the presence or absence of auto-QoS devices through conditional trusted interfaces.
Configures QoS classification
Configures egress queues
Detects the presence or absence of Cisco IP Phones
Configures QoS classification
Configures egress queues
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
Configuring Auto-QoS
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