CTC Union VDTU2-R240W, Руководство пользователя

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3 3 . . 5 5 . . 1 1 V V L L A A N N
VLAN (Virtual Local Area Network) allows a physical network to be partitioned into multiple logical networks. Devices
on a logical network belong to one group. A device can belong to more than one group. With VLAN, a device cannot
directly talk to or hear from devices that are not in the same group.
With MTU (Multi-Tenant Unit) applications, VLAN is vital in providing isolation and security among the subscribers.
When properly configured, VLAN prevents one subscriber from accessing the network resources of another on the
same LAN.
VLAN also increases network performance by limiting broadcasts to a smaller and more manageable logical broadcast
domain. In traditional switched environments, all broadcast packets go to each every individual port. With VLAN, all
broadcasts are confined to a specific broadcast domain.
User can choose three types of VLAN:Tag-Based VLAN and Port-Based VLAN. You can also set Disable the VLAN
function.
The VLAN Setup screen changes depending on whether you choose Tag-Based VLAN type and Port Based VLAN types
in this screen.
The IEEE 802.1Q defines the operation of VLAN bridges that permit the definition, operation, and administration of
VLAN topologies within a bridged LAN infrastructure.
T T a a g g - - B B a a s s e e d d V V L L A A N N
Click the Tag-Based VLAN to configure the Router.
In 802.1q, the VLAN information is written into the Ethernet packet itself. Each packet carries a VLAN ID (Virtual LAN
ID), called a tag. This allows VLANs to be configured across multiple switches. Note that it’s possible for VLAN tags to
be stripped by H/W and/or S/W.
When using 802.1q, four bytes are added to the Ethernet frame, of which 12 bits are used for the VLAN ID.
Theoretically, there can be up to 4096 VLANs per network.
An Ethernet packet that contains a VLAN ID is called a tagged packet. Conversely, an Ethernet packet with no VLAN ID
is called an untagged packet. Typically all packets leave untagged, unless tagged by the adapter prior to arriving at the