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.
Here are the expected behaviors of IP phones based on the different settings. If you find the behaviors of the IP Phone is not the same as your expectation, please refer below:
a. If the IP Phone is VLAN enabled and this VLAN is the same as Voice VLAN: The Switch will keep the Voice VLAN and assign the priority setting to the IP phone. The IP phone will only recognize the tagged traffic. In this case, port 1 in VLAN 100 on Switch should be set as tagged out (check the TX tagging box).
b. If the IP Phone is VLAN enabled and this VLAN is different from the switch’s Voice VLAN: The Switch will not apply any changes on the VOIP traffic of the IP Phone.
c. If the IP Phone is VLAN disabled: The Switch will assign the Voice VLAN and priority setting to the IP phone’s VOIP traffic. This setting causes the IP Phone to only send and receive untagged traffic. In this case, port 1 in VLAN 100 on Switch should be set as untagged out (uncheck the TX tagging box).
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.
SWITCHING > VLAN > VLAN Setup > Static VLAN > Add/Edit
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.
Note! You can write PVID 5 on * which will make all ports the same PVID:
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.
SWITCHING > VLAN > Voice VLAN Setup
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.
How to setup VLAN:
If you want to learn / know more about our VLAN design, please have a look here:
Setup Assistance, you´re looking for assisted configuration by our Professional Services Team? Please check here: Zyxel ConfigService Switch