When you are enabling AutoQoS for the Enterprise on a router, you should ensure the ip cef command has been issued before you issue the auto discovery qos command. Cisco Express Forwarding (CEF) must be enabled before you can implement AutoQoS for the Enterprise. AutoQoS uses Network Based Application Recognition (NBAR) for packet classification. If you find that CEF has not been enabled, you should enable it by issuing the ip cef command. After ensuring that CEF is enabled, you can issue the auto discovery qos interface configuration command, which will initiate the autodiscovery phase of the AutoQoS for the Enterprise implementation process. The autodiscovery phase profiles the traffic on the network to determine the volume and type of traffic being sent on the network. By default, autodiscovery will run for three days to determine as accurately as possible the volume and type of traffic sent on the network. However, you can configure autodiscovery to take more or less time, depending on the needs of the network.
You should issue the auto qos command after you issue the auto discovery qoscommand on an interface. After the auto discovery qos command has profiled the traffic, the auto qos command uses that data to generate Quality of Service (QoS) templates, which are then used to create class maps and policy maps. You can use the auto qos voip command if you are configuring AutoQoS Voice over IP (VoIP) rather than AutoQoS for the Enterprise.
The mls qos command enables QoS. This command is automatically enabled when you issue the auto qos command or the auto qos voip command, so it is not necessary to issue the mls qos command when you are configuring AutoQoS.