What are the benefits of voice VLAN?
What are the benefits of voice VLAN?
There are three main benefits to using voice VLAN.
First, it ensures that your VoIP (Voice over Internet Phone) devices do not have to directly interact with all broadcasts and other traffic from the data VLAN. It can be used to guarantee QoS on IP networks when multiple VLANs are configured and trunked on 802.1Q uplinks on the network switch.
Second, the voice VLAN can simplify network setup in some cases. It is much easier to mark packets for QoS than to specify different TCP and UDP port ranges. Similarly, TFTP and dedicated DHCP services for VoIP phones are easier to set up when all VoIP phones are on the same subnet.
Third, the voice VLAN can be used to prioritize different voice services because it supports 802.1p class of service (CoS) priority or DSCP (Differentiated Services Code Point) priority.
How does voice VLAN work?
To prioritize voice streams, they must first be identified. The Business VoIP VLAN can identify the voice data stream in two ways: one is by determining the source MAC address of the received packet (MAC address-based mode), and the other is by identifying the VLAN tag of the received packet (VLAN-based mode).
In the MAC address-based mode, the network switch can determine whether the data stream is a voice data stream according to the source MAC address field in the data packet arriving at its interface. As shown in the following figure, after the switch receives the data packet sent by the PC and the IP phone, it performs the following processing: if the source MAC address matches the OUI (organization unique identifier) configured on the switch, the VLAN voice tag is added to the packet And increased the priority of the packet. If the source MAC address does not match the OUI, the VLAN PVID tag will be added to the packet and the packet will not be sent first.
