LevelOne GEL-5261, User Manual

Page: 148 / 570

– 148 –
Chapter 5
| VLAN Configuration
IEEE 802.1Q VLANs
This switch supports the following VLAN features:
◆ Up to 4094 VLANs based on the IEEE 802.1Q standard
◆ Distributed VLAN learning across multiple switches using explicit tagging.
◆ Port overlapping, allowing a port to participate in multiple VLANs
◆ End stations can belong to multiple VLANs
◆ Passing traffic between VLAN-aware and VLAN-unaware devices
◆ Priority tagging
Assigning Ports to VLANs
Before enabling VLANs for the switch, you must first 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 the VLAN tags should be stripped off before
passing it on to any end-node host that does not support VLAN tagging.
Figure 74: VLAN Compliant and VLAN Non-compliant Devices
VA: VLAN Aware
VU: VLAN Unaware
VA VA VU
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 default VLAN ID of the receiving port). But if the
frame is tagged, the switch uses the tagged VLAN ID to identify the port broadcast
domain of the frame.