Question

Which of the following commands should you issue in interface configuration mode on the Catalyst 2950 switch to make the IP phone trust the CoS priority of incoming data packets generated by the attached host?

a) switchport priority extend cos
b) mls qos trust extend
c) mls qos trust cos
d) switchport priority extend trust

Answer 1

To have the IP phone trust the CoS priority of incoming data packets on a Catalyst 2950 switch, use the command 'mls qos trust cos' in interface configuration mode. This command prioritizes voice traffic for IP phones.

Step-by-step explanation:

To make the IP phone trust the Class of Service (CoS) priority of incoming data packets generated by the attached host on a Catalyst 2950 switch, you should use the following command in interface configuration mode:

mls qos trust cos

This command configures the switchport to trust the CoS value of incoming packets. In the context of an IP phone and its attached host, this allows the IP phone to prioritize voice traffic because voice traffic inherently has a higher priority due to its real-time nature. It ensures that the Quality of Service (QoS) for voice over IP (VoIP) traffic is maintained, even when traffic is coming from a device connected to the phone.