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treated as in the same broadcast domain and communicate as if they were on the same net segment, regardless of
their physical locations. 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. Different VLANs cannot
intercommunicate directly. Inter-VLAN communication can only be achieved using a router or other layer 3
devices that are able to perform Layer 3 forwarding.
2. Benefits of VLANs
Broadcast traffic and unicast traffic are confined to each VLAN, reducing bandwidth utilization and improving
network performance. VLANs are used for multiple reasons.
Better management and control of broadcast activity
VLANs conserve network resources by segmenting a large broadcast domain into several smaller broadcast
domains or VLAN groups and restrict all broadcast traffic to the VLAN on which the broadcast was initiated.
Reduced cost
The use of VLANs to create broadcast domains eliminates the need for routers to handle this function, permitting
operation at lower latencies and cost compared to routers under heavy load and at high cost.
Ease of network administration
Members of a VLAN group can be geographically dispersed as they are logically related instead of physically on
the same VLAN. Thus network administrators do not need to re-config the network when a VLAN member
changes its location. For example, in order to better collaborate with staffs from home or abroad on a special
project a workgroup is indispensable. Using VLAN, all workstations and servers that a particular workgroup uses
can be assigned to the same VLAN.
Tighter network security
Different VLANs cannot intercommunicate directly. Inter-VLAN communication can only be achieved using a
router or other layer 3 devices that are able to perform Layer 3 forwarding.
3. VLAN Mode
The switch provides 2 VLAN modes as below:
802.1Q VLAN Mode
IEEE 802.1Q is the networking standard that supports Virtual LANs (VLANs) on an Ethernet network. The
standard defines a system of VLAN tagging for Ethernet frames and the accompanying procedures to be used by
bridges and switches in handling such frames.
Port-based VLAN Mode (The switch operates in this mode by default)
Port-based VLANs limit traffic that flows into and out of switch ports. Thus, all devices connected to a port are
members of the VLAN(s) the port belongs to, whether there is a single computer directly connected to a switch, or
an entire department. Members of the same VLAN can intercommunicate. A user can belong to multiple VLANs
simultaneously. For example, if you want both user A and user B to communicate with user C while user A and user
B cannot intercommunicate, simply put user A and user C to a VLAN and user B and user C to the other VLAN.
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