A voice VLAN separates IP-phone traffic from a connected PC’s data traffic. The separation places voice and data in distinct VLANs and subnets, making voice traffic easier to identify and prioritize during congestion. section 10.0 section 10.1.1
An access port configured for voice VLANs carries two VLANs as an exception to ordinary access-port behavior: the data or access VLAN is untagged, while the voice VLAN is tagged. section 10.1.1 section 10.7
Cisco IOS configuration and verification
Configure the interface as an access port, assign VLAN 10 for data, and assign VLAN 20 for voice with switchport voice vlan 20. Verify the result with show interfaces f0/1 switchport; the output identifies static access mode, Access Mode VLAN 10, and Voice VLAN 20. section 10.1.1
JITL-SW1(config)# interface range f0/1-3 JITL-SW1(config-if-range)# switchport mode access #1 JITL-SW1(config-if-range)# switchport access vlan 10 #2 JITL-SW1(config-if-range)# switchport voice vlan 20 #2 JITL-SW1(config-if-range)# do show interfaces f0/1 switchport Name: Fa0/1 Switchport: Enabled Administrative Mode: static access #3 Operational Mode: static access #3 Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: native Negotiation of Trunking: Off Access Mode VLAN: 10 (VLAN0010) #4 Trunking Native Mode VLAN: 1 (default) Administrative Native VLAN tagging: disabled Voice VLAN: 20 (VLAN0020) #4 . . . #1 Manually configures access mode #2 Configures the data (access) and voice VLANs #3 F0/1 is an access port. #4 F0/1’s data and voice VLANs are listed.
Shows the complete interface-range configuration and annotated switchport verification output. section 10.1.1
