CTC Union VDTU2-R240W, Руководство пользователя

Страница: 29 / 59

28
the identification of 4096 (212) VLANs. Of the 4096 possible VIDs, a VID of 0 is used to identify priority frames and
value 4095 (FFF) is reserved, so the maximum possible VLAN configurations are 4,094.
The Router initially default configures one VLAN, VID=1.
A port such as LAN1 to 4, DSL or sniffing can have only one PVID, but can have as many VID as the Router has memory
in its VLAN table to store them.
Ports in the same VLAN group share the same frame broadcast domin thus increase network
performance through reduced boardcast traffic. VLAN groups can be modified at any time by adding, moving or
changing ports without any re-cabling.
Before enabling VLANs for the Router, you must first assign each port to the VLAN group(s) in which it will participate.
By default all ports are assigned to VLAN1 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 Router 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
Inter-connection devices, but the VLAN tags should be stripped off before passing it on to any end-node host that does
not support VLAN tagging.
VLAN Classification – When the Router receives a frame, it classifies the frame in one of two ways. If the frame is
untagged, the Router assigns the frame to an associated VLAN (based on the default VLAN ID of the receiving port).
But if the frame is tagged, the Router uses the tagged VLAN ID to identify the port broadcast domain of the frame.
Port Overlapping – Port overlapping can be used to allow access to commonly shared network resources among
different VLAN groups, such as file servers or printers.
Untagged VLANs – Untagged (or static) VLANs are typically used to reduce broadcast traffic and to increase security. A
group of network users assigned to a VLAN form a broadcast domain that is separate from other VLANs configured on
the Router. Packets are forwarded only between ports that are designated for the same VLAN. Untagged VLANs can be
used to manually isolate user groups or subnets.
PVID - VLAN ID assigned to untagged frames received on the interface. (Default: 1)
If an interface is not a member of VLAN 1 and you assign its PVID to this VLAN, the interface will automatically be
added to VLAN 1 as an untagged member. For all other VLANs, an interface must first be configured as an untagged
member before you can assign its PVID to that group.