Table of Contents
Advertisement
Tag-based VLANs
An IEEE 802.1Q VLAN is a group of ports located anywhere in the
network, but communicate as though they belong to the same physical
segment by using frame tags to indicate VLAN membership. Tagged
VLANs can help to simplify network management by allowing you to
move devices to a new VLAN without having to change any physical
connections. You can also configure the switch to interoperate with
existing tag-based VLAN networks and legacy non-tag networks by
specifying whether or not the switch ports transmit tagged frames.
Assigning Ports to VLANs – You must assign each port to the VLAN
group(s) in which it will participate. By default all ports are assigned to
VLAN 1 as untagged ports. Add a port as a tagged port if you want it to
carry traffic for one or more VLANs, and any intermediate network
devices or the host at the other end of the connection supports VLANs.
Then assign ports on the other VLAN-aware network devices along the
path that will carry this traffic to the same VLAN(s), either manually or
dynamically using GVRP. However, if you want a port on this switch to
participate in one or more VLANs, but none of the intermediate network
devices nor the host at the other end of the connection supports VLANs,
then you should add this port to the VLAN as an untagged port.
Note: VLAN-tagged frames can pass through VLAN-aware or VLAN-
unaware network interconnection devices, but should not be used
for any end-node host that does not support VLAN tagging.
VLAN Classification – When the switch receives a frame, it classifies the
frame in one of two ways. If the frame is untagged, the switch assigns the
frame to an associated VLAN (based on the PVID of the receiving port).
If the frame is tagged, the switch uses the tagged VLAN ID to identify the
port broadcast domain of the frame.
Port Overlapping – Port overlapping can be used to allow access to
commonly shared network resources among different VLAN groups, such
as file servers or printers. Note that if you implement VLANs which do
VLAN C
ONFIGURATION
3-29
Advertisement
Table of Contents
