10-10-2012, 01:53 PM
Virtual LAN
Virtual LAN.pptx (Size: 511.69 KB / Downloads: 55)
Local Area Networks (LAN)
Generally defined as a broadcast domain.
“Hubs, bridges, or switches on the same physical segment or segments connect end node devices”
A router is not needed for end nodes on the same LAN segment to communicate with each other.
However a router is necessary for these devices to communicate with devices on other LAN segments.
Why use VLAN's?
To the right, a LAN environment connected by switches.
Speed and latency advantages.
Drawback:
All end nodes (or hosts) are in same broadcast domain, which adds to the network a significant amount of traffic that is seen by all hosts.
Solution?
VLANs
VLAN
VLAN stands for Virtual Local Area Network.
A virtual local area network (VLAN) is a group of hosts with a common set of requirements that communicate as if they were attached to the same broadcast domain regardless of their physical location.
Configured through software rather than hardware. So it is extremely flexible.
VLANS create broadcast domains.
Broadcast Domain?
A broadcast domain is a network segment in which any network device can transmit data directly to another device without going through a router
LAN Vs VLAN
VLANs allow a network manager to logically segment a LAN into different broadcast domains . Since this is a logical segmentation and not a physical one, workstations do not have to be physically located together.
Users on different floors of the same building, or even in different buildings can now belong to the same LAN.
Virtual LAN
By utilizing VLANs, the same users can be spread out over various geographical locations and still remain in their same IP subnet (broadcast domain).
A VLAN is a broadcast domain created by one or more switches.
The network design above creates three separate broadcast domains.
Benefits of VLANs
Geographically separated users on the same IP subnet (broadcast domain)
Limit the size of broadcast domains and limit broadcast activity
Security benefits by keep hosts separated by VLAN and limiting what devices can talk to those hosts
Cost savings as you don’t need additional hardware and cabling
Operational benefits because changing a user’s IP subnet (Broadcast Domain) is in software
Conclusion
VLANs are cost and time-efficient.
VLAN can reduce network traffic, and provide an extra measure of security.
A VLAN is configured by software, not by hardware(physically wiring).