Panasonic KX-NCP500, Networking Manual

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1.2.2 VLAN (Virtual LAN)
VLANs are logical segments within a corporate LAN. By assigning VLAN settings to IP telephones, it is possible
to separate the packets transmitted by an IP telephone 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 telephones (e.g., KX-NT300 series) 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
telephone, whereas VLAN settings for the secondary port apply to data transmitted by a PC connected to the
IP telephone. When sending packets, the IP telephone 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 telephone
voice transmissions.
In this way, an IP telephone with 2 ports can transmit voice packets from the primary port with higher priority
than other packets from the secondary port.
PBX
IP Telephone with 2 ports
VLAN 1
VLAN 1
VLAN 1
VLAN 2
VLAN 2
VLAN 1
Segment for Voice Data
VLAN 2
Segment for Other Data
Voice Packet
Other Packet
PC
PC
Other Packet
VLAN 2
VLAN-capable Switching Hub
Primary Secondary
Note
•
This VLAN feature complies with IEEE (Institute of Electrical and Electronics Engineers) 802.1Q.
•
The PBX receives VLAN settings only from the connected switching hub. Therefore, VLAN settings for
the PBX must be assigned at the switching hub.
8 IP Networking Guide Document Version 2010-08
1.2.2 VLAN (Virtual LAN)