When configuring AutoQoS VoIP on a Cisco Catalyst switch how is the configuration performed?
A.
The auto qos voip command is applied to each interface.
B.
The auto qos voip command is applied globally in the switch.
C.
Each interface will need either the auto qos voip cisco-phone or auto qos voip trust on each interface depending on the upstream device.
D.
Each interface will need either the auto qos voip trust cisco-phone or auto qos voip trust trust on each interface depending on the upstream device.
Explanation:
The QoS mechanisms on a Catalyst switch differ from those QoS mechanisms found on a router. For example, while a router uses LLQ as a priority queuing strategy, a Catalyst switch might use weighted round-robin (WRR) as a priority queuing strategy. Fortunately, the AutoQoS feature available on some Catalyst switch models applies voice-specific QoS features globally to a Catalyst switch and also at the port level. To configure AutoQoS on supported Catalyst switch platforms, issue the following command from interface configuration mode:
Switch(config-if)#auto qos voip [trust | cisco-phone] If the trust option is used in the previous command, the Catalyst switch makes queuing decisions based on Layer 2 Class of Service (CoS) markings. However, if the cisco-phone option is used, the Catalyst switch makes queuing decisions based on CoS markings originating from a Cisco IP phone. The switch detects the presence of a Cisco IP phone via the CDP.
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ftautoq1.html