PLANET SGSW-24040 - Manual (Page 121)

User’s Manual of SGSW-24040 / 24240 Series
121
4.6 VLAN
4.6.1 VLAN Overview
A Virtual Local Area Network (VLAN) is a network topology configured according to a logical scheme rather than the physical
layout. VLAN can be used to combine any collection of LAN segments into an autonomous user group that appears as a single
LAN. VLAN also logically segment the network into different broadcast domains so that packets are forwarded only between
ports within the VLAN. Typically, a VLAN corresponds to a particular subnet, although not necessarily.
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 physically 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.
1. 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.
2. The Managed Switch supports IEEE 802.1Q VLAN. The port untagging function can be used
to remove the 802.1 tag from packet headers to maintain compatibility with devices that are
tag-unaware.
3. The Switch's default is to assign all ports to a single 802.1Q VLAN named DEFAULT_VLAN.
As 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.
This section has the following items:
 IEEE 802.1Q VLAN Enable IEEE 802.1Q Tag based VLAN group
 IEEE 802.1Q Tunneling Enables 802.1Q (QinQ) Tunneling
 Private VLAN Creates/removes primary or community VLANs
4.6.2 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