S Layer 2 Managed Switch User Manual
陈泽科技有限公司
www.stephen-tele.com
21
Divide different VLAN according to IEEE802.1Q Tag VLAN’s VID. When data frames go through switch, switch identifies the
VLAN they belong to according to Tag Header of the frame. (If there is no Tag Header in the frame, we call this frame as Untag
frame. We will use the default VID message to identify their VLAN. Also we can process differently to Untag frame through
configuration.). All frames that belong to this VLAN in spite of unicast frame,multicast frame or broadcast frame will be
limited to transmission within this logic VLAN. Hosts in the group can communicate each other without other host’s influence
just as they exist in a single LAN.
S
switch supports IEEE802.1Q Tag VLAN. When you configure VLAN, there are several configurations should be
considered:
VLAN ID: VLAN configuration mark symbol. Used to mark some VLAN.
S
can accept VLAN ID from 1-4094.
VLAN domain broadcast: used to define forwarding range of VLAN frame. Ports that are not in VLAN domain broadcast
will not receive any frame from this VLAN. For members of this VLAN broadcast domain ports, you can configure this
member’s attribute as TAG or UNTAG. If it is configured as TAG member, data frame comes from this port will be marked
VLAN TAG. The VLAN ID in this VLAN TAG is the VLAN ID belongs to this VLAN broadcast. If it is configured as UNTAG
member, data frame comes from this port will not be marked VLAN TAG.
S supports 256 VLAN domains broadcast.
Default port VID: When switch can not acquire the frame belongs to which VLAN from Tag header of the frame ( we
called this frame as Untag frame), switch will determine which VLAN that this frame belongs to through default VID that
the frame goes through switch’s port.
S
supports 256 groups IEEE802.1Q VLAN. You can configure several VLAN at the same time and one port can belong
to multiple VLAN. There is a VLAN table in the switch. A VLAN table corresponds to a VLAN domain. All data packet that go
through
S
will check VLAN table according to VLAN ID that carried by the data packet (if there is no VLAN TAG in
data packet, according to PVID). If there is a relative broadcast table to VLAN ID and the port that this packet will go to is in
VLAN broadcast domain, then this packet can send from this port normally. Otherwise this packet will be dropped. When it is
sending, switch will determine the port’s attribute in VLAN broadcast domain is TAG or UNTAG, if it is TAG, it will send data
packet with VLAN TAG mark. Followed is a simple figure to configure 802.1Q VLAN.