Allied Telesis AT-S39 - Manual (Page 154)

Section II: Local and Telnet Management
154
Multiple VLAN Modes Overview
The Multiple VLAN modes simplify the task of configuring the switch in
network environments that require a high degree of network
segmentation. In the multiple VLAN modes, 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 the
ports with access to the uplink port.
The AT-S62 software supports two types of multiple VLAN modes:
❑ 802.1Q-compliant Multiple VLAN mode
❑ Multiple VLAN mode (also referred to as non-802.1Q compliant
Multiple VLAN mode)
Note
Multiple VLAN modes are supported only in single switch (i.e. edge
switch) environments. This means that cascading of switches while
in a multiple VLAN mode is not allowed.
Activating a multiple VLAN mode 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 VLAN
mode) is configured as the uplink port.
Activating a multiple VLAN mode on cascaded switches can also
affect enhanced stacking as the master switch may not be able to
detect member switches beyond the first cascaded switch.
802.1Q-
Compliant
Multiple VLAN
Mode
802.1Q-compliant Multiple VLAN mode is appropriate when the device
connected to the uplink port is 802.1Q compatible, meaning that it can
handle tagged packets.
This mode places each port on the switch into a separate VLAN as an
untagged port. Each VLAN also contains a user designated uplink port.
This uplink port, which is a tagged port, is shared by all the VLANs on the
switch. There can be only one uplink port on a switch.
The VLANs are called client VLANs. The VLAN names, the VIDs, and the
PVIDs are based on port number. For example, the VLAN for Port 4 is
named Client_VLAN_4 and is given the VID of 4, the VLAN for Port 5 is
named Client_VLAN_5 and has a VID of 5, and so on. PVIDs are also
assigned automatically. For example, the PVID for Port 4 is 4, to match
the VID of 4.