Instruction Manual
52
VLAN can enhance performance by conserving bandwidth, and improve security
by limiting traffic to specific domains.
A VLAN is a collection of end nodes grouped by logic instead of physical location.
End nodes that frequently communicate with each other are assigned to the
same VLAN, regardless of where they are on the network. Logically, a VLAN can
be equated to a broadcast domain, because broadcast packets are forwarded to
only members of the VLAN on which the broadcast was initiated.
No matter what basis is used to uniquely identify end nodes and assign these
nodes VLAN membership, packets cannot cross VLAN without a network device
performing a routing function between the VLAN.
The Managed Switch supports IEEE 802.1Q VLAN. The port untagging function
can be used to remove the 802.1Q tag from packet headers to maintain
compatibility with devices that are tag-unaware.
The switch's default is to assign all ports to a single 802.1Q VLAN named
DEFAULT_VLAN. As a new VLAN is created, the member ports assigned to the new
VLAN will be removed from the DEFAULT_ VLAN port member list. The DEFAULT_
VLAN has a VID = 1.
IEEE 802.1Q VLAN
In large networks, routers are used to isolate broadcast traffic for each subnet
into separate domains. This Managed Switch provides a similar service at Layer 2
by using VLANs to organize any group of network nodes into separate broadcast
domains. VLANs confine broadcast traffic to the originating group, and can
eliminate broadcast storms in large networks. This also provides a more secure
and cleaner network environment.
An IEEE 802.1Q VLAN is a group of ports that can be located anywhere in the
network, but communicate as though they belong to the same physical segment.
VLANs help to simplify network management by allowing you to move devices
to a new VLAN without having to change any physical connections. VLANs
can be easily organized to reflect departmental groups (such as Marketing or
R&D), usage groups (such as e-mail), or multicast groups (used for multimedia
applications such as videoconferencing).
VLANs provide greater network efficiency by reducing broadcast traffic, and
allow you to make network changes without having to update IP addresses or IP
subnets. VLANs inherently provide a high level of network security since traffic
must pass through a configured Layer 3 link to reach a different VLAN.
This Managed Switch supports the following VLAN features:
