Auto-QoS

CCIP 642-642 QoS Q&A – Modular QoS CLI (MQC) and Auto-QoS (6-10)

Section 3 – Modular QoS CLI (MQC) and Auto-QoS

QUESTION 6
When configuring a Cisco Catalyst switch to accommodate an IP phone with an attached PC, it is desired that the trust boundary be set between the IP phone and the switch. Which two commands on the switch are recommended to set the trust boundary as described? (Choose two.)
A.    mls qos trust extend [cos value]
B.    no mls qos trust dscp
C.    mls qos trust cos
D.    mls qos trust device cisco-phone
E.    switchport priority extend trust
F.    mls qos cos 5
Answer: CD

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CCIP 642-642 QoS Q&A – Modular QoS CLI (MQC) and Auto-QoS (1-5)

Section 3 – Modular QoS CLI (MQC) and Auto-QoS

QUESTION 1
A Cisco Catalyst switch has an IP phone connected to its Fastethernet0/2 port. The IP phone has an attached PC. The Fastethernet0/2 port on the switch has been configured with the commands mls qos trust cos, mls qos trust device cisco-phone, and switchport priority extend trust.
What will happen to a data frame with a CoS of 5 that is sent from the PC through the IP phone to port Fastethernet0/2 on the switch?
A.    The IP phone will, by default, overwrite the switch CoS value and mark the data packet as CoS 0.
B.    The IP phone will allow the data packet through without modifying the CoS settings of the data frame.
C.    The switch will instruct the phone to allow the packet through without modification only if the phone has been configured to do so.
D.    While the packet will pass through the IP phone without modification, the switch will, by default, override the CoS priority with the switch default CoS priority.
Answer: B

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