Explanation/Reference:
Explanation:
A (not D): The Voice VLAN feature in EX-series switches enables access ports to accept both data (untagged) and voice (tagged) traffic and separate that traffic into different VLANs.
B: To assign differentiated priority to Voice traffic, it is recommended that class of service (CoS) is configured prior to enabling the voice VLAN feature. Typically, voice traffic is treated with a higher priority than common user traffic. Without differentiated treatment through CoS, all traffic, regardless of the type, is subject to the same delay during times of congestion.
C: In conjunction with Voice VLAN, you can utilize Link Layer Discovery Protocol Media Endpoint Discovery (LLDP-MED) to provide the voice VLAN ID and 802.1p values to the attached IP phones. This dynamic method associates each IP phone with the appropriate voice VLAN and assigns the necessary802.1p values, which are used by CoS, to differentiate service for voice traffic within a network.
Reference: https://kb.juniper.net/InfoCenter/index?page=content&id=KB11062&actp=search