A separate VLAN is needed for voice traffic.Refer to curriculum topic: 6.1.2A PC commonly connects to an IP phone and the IP phone, in turn, connects to a switch. The phone does not require a separate port. Because voice traffic cannot tolerate much packet delay, it needs to be in a separate VLAN. The voice VLAN can be configured to provide quality of service (QoS), which will ensure that the voice traffic has a higher priority than data traffic. Explanation: If an organization is changing to include Cisco IP phones in its network, the design feature that must be considered to ensure voice quality is Quality of Service (QoS). QoS can be implemented in a network to give priority to certain types of traffic, such as voice traffic, over other types of traffic. This ensures that voice traffic is not delayed or dropped when there is congestion in the network.