Voice VLAN on Zyxel GS1920

Nowadays, IP phones are commonly used in office environments, to give voice traffic a higher priority is an important consideration when designing a network. In a common scenario of the installation, the IP phone is connected to a switch while linking the PC or laptop on the other end, bridging both devices. In this case, Voice VLAN is an important feature used to easily mark and prioritize voice packets from IP phone, separating data packets from the PC. In the following configuration guide, the goal to achieve is to separate traffic between the IP phone and PC without having to set individual VLAN tags for them. The switch will add VLAN tags for voice & data packets separately upon receiving them and then forwarded these to the uplink.

1.Configuration (Create VLAN interfaces)
*Create a VLAN for voice packets transmission, select ports
which are connected to IP phone, unselect Tx tagging as to
save efforts of configuring VLAN on each phone.

*Create another VLAN for data packets, select member ports, unselect Tx tagging.

On the uplink port enable Tx tagging to transmit packets with VLAN tags

3 Configure PVID to separate data packets from voice packets. PVID number should be the same as the VLAN number created for data packets.

After setting PVID for data packets, next step is to configure “Voice VLAN” feature for the switch to identify the voice packets.

2.Configure Voice VLAN
*Configure Voice VLAN number and priority to prioritize the voice packets. The Voice VLAN number should be the same as the VLAN number created earlier for voice service packets.

*Specify the OUI addresses. OUI are the first 3 bytes of a MAC address that represents the vendor. By specifying the IP phone MAC address, the switch can identify voice traffic accordingly. Zyxel switch supports up to 6 vendor OUIs.

This guide demonstrates the ease of configuring Voice VLAN on standalone switches. In general, separating VLANs and determine rules for data and voice achieved the goal of prioritizing voice traffic without additional configuration on the IP phones. The applicable model for standalone switches are our GS1920 series and above.