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2.4 VLAN Function
The switches support two VLAN modes. One is Port-based VLAN and the other is 802.1Q VLAN.
The following configuration are supported:
1.
VLAN Mode: Port-based mode or 802.1Q mode
2.
VLAN mapping table setup: member ports setup for each group
3.
Per port PVID setup: PVID setting, Tag mode setting
Port -based VLAN Mode
1.
This mode supports 16 VLAN groups, Group 0 ~ Group 15.
2.
Packet forwarding is performed only among the member ports in the same group.
3.
Every packet, tagged or untagged, is forwarded from the input port to the output port transparently
without any packet modification.
4.
Per port PVID setting is used for the index to the VLAN Group table. When a packet is received, the
associa ted PVID setting of the input port is used to map to one VLAN group in the VLAN group
table. The mapping index is retrieved from the least 4 bits (bit 3~0) of the PVID value.
5.
Tag mode settings are preset with an untagged mode for all ports and not changeable in Port-based
VLAN mode.
6.
VLAN tag in every input tagged packet is ignored.
NOTE
:
To provide more flexibility for LAN administrator in performing web management task, the internal
MNG port that connects to the built- in Http server is disclosed for PVID configuration. The MNG port
is also configured as the member port for all VLAN groups and permanently as an untag port.
802.1Q VLAN Mode
1.
This mode supports 16 VLAN groups, Group 0 ~ Group 15.
2.
When an untagged packet is received, the associated PVID setting of the input port is used to
map to one VLAN group in the VLAN group table. The mapping is retrieved from the least 4
bits (bit 3~0) of the PVID value.
3.
When a tagged packet received, the VLAN ID value of the received packet is used to map to
one VLAN group in VLAN group table. The mapping index from the least 4 bits (bit 3~0) of
the VLAN ID value.
4.
Packet forwarding is performed only among member ports in the same group. If the input port
of the received packet is not a member port of the mapped group, the packet is dropped.
5.
For outbound, Tag mode of the output port is applied as follows:
Received untagged packet output to:
Tag port:
The packet is inserted with PVID of the input port as VLAN ID and new CRC.
Untag port:
The packet is forwarded with no change.
Received tagged packet output to:
Tag port:
The packet is forwarded with no change.
Untag port:
The VID of the packet is removed and forwarded with new CRC.
Note:
When VLAN mode is set from 802.1Q mode to Port-based mode, all ports are set to Untag ports
automatically.
