Are there any more Zyxel switches between this switch and
destination?
If there are switches, access the next uplink switch and repeat step 2.
If there are no switches, proceed to next agenda.
Verify whether device with issue’s incoming packets are
tagged or not.
This usually means that if the MAC address of the device is not processed in the
configured PVID, then packets are most likely already tagged when reaching
this Zyxel switch or another feature has forced the packet to be process in a
different VID.
Most end devices usually sends untagged packets up the network. Devices
like IP phones, Access Points, and neighboring switches, on the other hand,
have the possibility of sending tagged packets.
After verifying whether packets are tagged or untagged, go to step 6.
Is the PVID configured correctly?
The PVID decides which VLAN an untagged packet will be processed in. You
can disregard PVID configurations if the downlink device has already tagged
the device with issue’s packets correctly.
WebGUI:
Figure 6 Advance Application>VLAN>VLAN Configuration>VLAN Port Setup