PLANET VIP-2020PT - Manual (Page 54)

Enterprise HD PoE IP Phone
VIP-2020PT
In chart 1, there is a layer 2 that switches go without setting VLAN. Any broadcast frame will be
transmitted to the other ports except the send port. For example, a broadcast information is sent
out from port 1 then transmitted to ports 2, 3 and 4.
In chart 2, red and blue indicate two different VLANs in the switch, and port 1 and port 2 belong
to red VLAN, port 3 and port 4 belong to blue VLAN. If a broadcast frame is sent out from port 1,
switch will transmit it to port 2, the other port in the red VLAN and not transmit it to port3 and port
4 in blue VLAN. By this means, VLAN divides the broadcast domain via restricting the range of
broadcast frame transition.
Chart 2 uses red and blue to identify the different VLANs, but in practice, VLAN
uses different VLAN IDs to identify.