KTI KS-2300, User Manual

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If a port in VLAN is set to untagged port, all the packets sent out from the
port will be no tag in side (untagged). If these packets are tagged when
they come to the switch, the tag will be removed when they are transferred
from this port. Because lots of living network devices does not support tag
in packet (untagged device), they cannot recognize tagged packets. In that
case, you have to set their connection port to untagged.
If a port in VLAN is set to tagged port, all the packets sent out from the port
will be tag inside (tagged). If these packets are untagged when they come
to the switch, a tag will be added when they are transferred from this port.
In this case, it will use the PVID set on the ingress port as the VLAN ID in the
added tag.
PVID (Port VLAN ID) is the VLAN ID setting on an untagged port. When
untagged packets come to the port, the switch will check the VLAN setting
whose VLAN ID is the same as PVID and decide to drop for forward the
packets.
[ Q7 ] Why my network connection cannot work immediately when I add or
change my network connection on the switch ? It always delays 30
seconds and then start to work.
[ A ] You can check the spanning tree configuration first. If spanning tree is
enable, it will take about 30 seconds before any new connection starting to
work because it will check the network configuration to prevent any looping
happening in the network first. That is a correct for spanning tree operation.
[ Q8 ] What is flooding ?
[ A ] Flooding happens when packets come to the switch and the switch
cannot find their DA (Destination Mac Address) in its Mac learning table. In
this case, the switch will forward these packets to every port to find the
destination network devices. This operation is called flooding.
[ Q9 ] Why the traffic in the trunk connection is not shared to every port
when only several connections works between the switches ?
[ A ] For a DA-SA pair, its traffic are assigned to be transferred through one
cable of the trunk only but not every cable. If only several connections
works on the trunk connection, only part of the cables in the trunk are
working. Because the traffic is not heavy in that case, part of the cables in
the trunk is enough for the loading. If more DA-SA pairs are working in the
trunk, they will be assigned to different cables to share the loading in the
trunk. If there are many DA-SA connections in the trunk and their value are
quite random, the traffic will be shared on every cable of the trunk smoothly.