VLANs are logical segments within a corporate LAN. By assigning VLAN settings to IP-PTs, it is possible to
separate the packets transmitted by an IP-PT according to the type of data, and specify which VLAN each data
type will be sent over. This allows you to avoid generating unnecessary network traffic on each segment, and
to reduce the load on the network. As a consequence, speech quality can be assured.
Therefore, we recommend using the VLAN feature to perform VoIP communication effectively.
Some IP-PTs (e.g., KX-NT136) are equipped with 2 ports, primary and secondary, for packet communication.
Allocating these ports to different VLANs enables you to split the paths for packets depending on whether the
packet contains voice signals or data.
VLAN settings (VLAN ID and VLAN priority) for the primary port affect voice data transmitted by the IP-PT,
whereas VLAN settings for the secondary port apply to data transmitted by a PC connected to the IP-PT. When
sending packets, the IP-PT can attach information on which VLAN the packets are to be transmitted over
(VLAN Tagging). The switching hub that receives these packets reads the VLAN information and sends the
packets over the appropriate VLAN. This helps to ensure bandwidth for IP-PT voice transmissions.
In this way, an IP-PT with 2 ports can transmit voice packets from the primary port with higher priority than
other packets from the secondary port.