What is Virtual Local Area Network

Virtual Local Area Network: VLAN stands for Virtual Local Area Network.

• A VLAN allows a network administrator to create groups of logically networked devices that act as if they are on their own independent network, even if they share a common infrastructure with other VLANs.
• Using VLANs, you can logically segment switched networks based on functions, departments, or project teams.
• VLANs allow the network administrator to implement access and security policies to particular groups of users.

• VLAN is an independent LAN Network.
• A VLAN allows student and faculty PCs to be separated although they share the same infrastructure.
• A VLAN is a logically separate IP sub network.
• VLANs allow multiple IP networks and subnets to exist on the same switched network.
• For computers to communicate on the same VLAN, each must have an IP address and a subnet mask that is consistent for that VLAN.
• The switch has to be configured with the VLAN and each port in the VLAN must be assigned to the VLAN.
• In the below figure you can see that although there are six computers on this network, there are only three broadcast domains: Faculty, Student, and Guest.

There are main three types of VLAN Configuration possible:-

1. Port-based VLANs:- Uses the physical layer port number on the front of the VLAN switch to assign computers to VLAN segments
2. MAC-based VLANs:- Uses the data link layer address to form the VLANs
3. IP-based VLANs:- Uses the network layer address to form the VLANs

Advantages of VLAN

1. Security – Groups that have sensitive data are separated from the rest of the Network, decreasing the chances of confidential information breaches. Faculty Computers are on VLAN 10 and completely separated from student and guest data
2. Cost reduction – Cost savings result from less need for expensive network upgrades and more efficient use of existing bandwidth and uplinks.
3. Higher performance – Dividing flat Layer 2 networks into multiple logical workgroups (broadcast domains) reduces unnecessary traffic on the network and boosts performance.
4. Broadcast storm mitigation – Dividing a network into VLANs reduces the number of devices that may participate in a broadcast storm.

• Point-to-Point Tunneling Protocol (PPTP): This protocol is developed by Microsoft. PPTP keeps proprietary data secure even when it is being communicated over public networks. Authorized users can access a private network called a virtual private network, which is provided by an Internet service provider. This is a private network in the “virtual” sense because it is actually being created in a tunneled environment.
• Layer Two Tunneling Protocol (L2TP): This type of tunneling protocol involves a combination of using PPTP and Layer 2 Forwarding.