needed can vary, depending on the volume and nature of traffic on your network. By default, Auto Discovery runs for three days. The Cisco AutoQoS template generation and installation phase generates templates from the data collected during the Auto Discovery phase, and installs the templates on the interface. Cisco AutoQoS then uses these templates as the basis for creating the class maps and policy maps for your network. After creating the class maps and policy maps, Cisco AutoQoS installs them on the interface. Cisco AutoQoS VoIP omits the Auto Discovery phase and it goes straight to template generation and installation. Phase 1: Traffic Profiling on Routers with Auto Discovery
Initiate the Auto Discovery phase by using the auto discovery qos command on the selected interface as shown in Figure . Before using the auto discovery qos command at the interface or ATM PVC, ensure you meet these prerequisites as shown in Figure :

• Confirm CEF is enabled.
• If the interface or subinterface has a link speed of 768 kbps or lower, configure the primary or secondary IP address of the interface by using the ip address command.
• For all interfaces or subinterfaces, configure the amount of bandwidth by using the bandwidth command. Allocate bandwidth amount based on the link speed of the interface.
• For ATM PVCs, configure the variable bit rate (VBR) by using either the vbr-nrt command or the vbr-rt command, or configure the constant bit rate (CBR) by using the cbr command.

When running Auto Discovery, observe these restrictions:

• The auto discovery qos command is not supported on subinterfaces.
• Do not change the bandwidth of the interface when using the auto discovery qos command.
• You must remove all previously attached policies from the interface.

The optional trust keyword indicates that the DSCP markings of a packet are trusted (that is, relied on) for classification of voice, video, and data traffic. If you do not specify the optional trust keyword, Cisco AutoQoS classifies voice, video, and data traffic using NBAR, and the packets will be marked with the appropriate DSCP value. Note these points about the Auto Discovery phase:

• If you want to stop Auto Discovery, use the no auto discovery qos command. This command stops data collection and removes any data collection reports it generated.
• If you want to view the Auto Discovery temporary results while discovery is in progress, use the show auto discovery qos command. This command displays the results of the data collected up to that point during the Auto Discovery phase.

Figure is an example of an Auto Discovery output on which the QoS policy will be built. Phase 2: Configuring QoS Policies on Routers
The auto qos command generates Cisco AutoQoS for the Enterprise templates based on data collected during the Auto Discovery phase and then installs the templates on the interface. AutoQoS uses these templates to create class maps and policy maps for your network and then installs them on the interface. Figure shows the command syntax for configuring Cisco AutoQoS. To remove Cisco AutoQoS from the interface, use the no form of the auto qos command. You can also use the auto qos command to enable Cisco AutoQoS VoIP, which does not benefit from prior Auto Discovery. If you are using any of the earlier Cisco IOS software releases in connected routers that only support Cisco AutoQoS VoIP, use the voip keyword to generate Cisco AutoQoS VoIP templates. For Cisco AutoQoS VoIP, the optional trust keyword is used to trust (that is, rely on) the DSCP markings for classification of voice traffic. If you do not specify the optional trust keyword, Cisco AutoQoS classifies voice traffic using NBAR, and marks the packets with the appropriate DSCP value. The optional fr-atm keyword enables Cisco AutoQoS VoIP for the Frame Relay-to-ATM interworking links. This option is available on the Frame Relay DLCIs for Frame Relay-to-ATM interworking only. Example: Cisco AutoQoS for the Enterprise Router Configuration
Figure shows an example of Cisco AutoQoS for the Enterprise configuration on a router interface. The correct configuration procedure is as follows: Step 1 On the interface, first configure the offered bandwidth using the bandwidth command, configure the IP address using the ip address command, and configure the DLCI address using the frame-relay interface dlci command if you are configuring a Frame Relay subinterface. Step 2 Activate the Auto Discovery phase using the auto-discovery qos command. For the most accurate traffic analysis, leave the Auto Discovery phase running for as long as possible, preferably several days. In the Auto Discovery phase, the generated policy can optionally be reviewed using show auto discovery qos. Step 3 Apply the generated Cisco AutoQoS policy to the interface using the auto qos command. At this point, the Cisco AutoQoS configuration is complete, but you can tune the autogenerated classification and policies if necessary. Example: Configuring Cisco AutoQoS for the Enterprise on a High-Speed Serial Interface
The example in Figure shows Cisco AutoQoS configured on the high-speed serial 1/2 interface. As shown, leave Auto Discovery running, preferably for several days. Example: Configuring Cisco AutoQoS for the Enterprise on a Low-Speed Serial Interface
The example in Figure shows Cisco AutoQoS configured on the low-speed serial 1/3 interface.

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Content 5.1 Introducing Cisco AutoQoS 5.1.8 Verifying Cisco AutoQoS The verification of Cisco AutoQoS typically follows the procedure shown in the table in Figure . The principle behind the procedure is the same for routers and switches, with the exception that there is no Auto Discovery phase on switches and therefore there is no requirement to verify its results. The major command used for verification on both routers and switches is show auto qos. The interface-specific configuration is examined afterward. Because Cisco Catalyst switches use the CoS-to-DSCP maps for egress packet queuing, you can use the show mls qos maps command to verify how Cisco AutoQoS defined these maps. Monitoring Cisco AutoQoS on Routers
Follow these three steps to monitor Cisco AutoQoS on Cisco routers: Step 1 Display the data collected during the Auto Discovery phase:

• Use the show auto discovery qos command to display the data collected during the Auto Discovery phase of Cisco AutoQoS for the Enterprise. Figure shows the command syntax and an example.
• The suggested policy output lets you preview class maps and policy maps before you issue the auto qos command on the interface. You can then continue with the Auto Discovery phase to gather more data (it is recommended that you run Cisco AutoQoS discovery for several days), or you can copy the existing discovery results into a text editor and modify the autogenerated classification and policies as desired.
• The optional interface keyword indicates that only the configurations for the specific interface type is displayed.

Step 2 Examine Cisco AutoQoS templates and initial configuration:

• The show auto qos command is used to display the Cisco AutoQoS interface templates, policy maps, class maps, and ACLs. Figure shows the show auto qos command syntax and sample output.
• When the interface keyword is used along with the corresponding interface type argument, the command displays the configurations created by Cisco AutoQoS on the specified interface. When the interface keyword is used but an interface type is not specified, the command displays the configurations created by the AutoQoS on all the interfaces or PVCs on which the AutoQoS has been