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VLAN is a subnetwork or segment of a local area network configured by

software, not by physical wiring.

Why segment LAN into several VLAN?

one reason for segmentation is to make broadcasting possible at the data

link layer. In other word, the stations in each segment form a group that

can be the receive of a broadcast message. The message can come from

some station in the group or from another station outside of the group.

If a person move from one group to another, there is no need to change

the physical configuration while in LAN this require change the physical

configuration

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VLAN1

VLAN2

VLAN3

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To achieve privacy, organization can use three strategies:-

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Today, most organizations need to have privacy in intra- organization data exchange, but, at the

same time, they need to be connected to the global internet for data exchange with other

.organizations. One solution is the use of a hybrid network

Hybrid network allows anorganizations to have its own private internet and, at the

same time, access to the global Internet.

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Both private and hybrid networks have a major drawback:Cost

. VPN allows organizations to use the global Internet for both purposes

VPN creates a network that isprivate but virtual. It is private because it guarantee privacy

inside the organization. It is visual because it does not use real private WAN the network is

.physically public but virtually private