Allied Telesis AT-S63 - Manual (Page 297)

AT-S63 Management Software Features Guide
Section VI: Virtual LANs 297
Overview
The multiple VLAN modes are designed to simplify the task of configuring
the switch in network environments that require a high degree of network
segmentation. In a multiple VLAN mode, the ports on a switch are
prohibited from forwarding traffic to each other and are only allowed to
forward traffic to a user-designated uplink port. These configurations
isolate the traffic on each port from all other ports, while providing access
to the uplink port.
The AT-S63 Management Software supports two types of multiple VLAN
modes:
ˆ 802.1Q-compliant Multiple VLAN mode
ˆ Multiple VLAN mode (also referred to as non-802.1Q compliant
Multiple VLAN mode)
Each mode uses a different technique to isolate the ports and their traffic.
The first method uses VLANs while the second uses port mapping. The
uplink port is also different in each mode. In one the port is a tagged port
and in the other untagged. This is explained in the following subsections.
Note
The multiple VLAN mode feature is supported only in single switch
(i.e. edge switch) environments. This means that cascading of
switches while in Multiple VLANs mode is not allowed.
Configuring multiple VLANs on a cascaded switch can possibly
result in disconnection of network paths between switches unless
the port used to link the switch (being configured for multiple VLANs
mode) is configured as uplink VLAN port.
Configuring multiple VLANs on cascaded switches can also affect
enhanced stacking because the master switch may not be able to
detect member switches beyond the first cascaded switch.