A VLAN represents a broadcast domain that is isolated and logically partitioned in a computer network at a data link layer. A VLAN applies tags to the network frames and handles these tags in a networking system to create the appearance and functionality of network traffic that is physically on a single network but which acts as if it is split between separate networks. It can keep network applications separate despite being connected to the same physical network without requiring multiple sets of cabling and networking devices to be deployed.
VLAN greatly simplifies the network design and deployment. It groups the hosts together even if the hosts are not directly connected to the same network switch. It allow networks and devices to share the same physical cabling without interacting, improving simplicity, security, traffic management and economy. Early network designers often segmented physical LANs with the aim of reducing the size of the Ethernet collision domain with the aim of improving performance. However, since each switch port is a collision domain attention turned to reducing the size of the data link layer broadcast domain. Thus, VLANs were first employed to separate the several broadcast domains across one physical medium.
VLANs are used to achieve multiple purposes. Some benefits of VLANs includes the followings:
- VLAN helps in reducing the administration cost for the organization by helping them to efficiently use their network devices. The stacking and prioratization of the switches to act collectively as a VLAN for a specific purpose leads organization to reduce the overall cost of networking by using different VLANs for different purposes.
- VLAN helps in increaseing the broadcast domain thus reducing their sizes. By using the same switch to connect multiple end user computers VLAN helps to manage the broadcast domain sizes by assigning single broadcast for a collection of routers and switches connected for a specific VLAN purpose. VLAN encourages better control of multicast traffic as well as broadcast domains since certain devices send out massive amounts of traffic during broadcasting
- VLAN offers security because routers provide communication and firewalls between VLAN groups. The firewall helps to prevent unauthorized packets to get transmitted into the VLAN thus enhancing the performance of the network. VLAN ensures that non-members cannot receive their broadcasts .
- VLAN for its very important feature allows logical grouping of users. VLAN makes it easy to evaluate traffic patterns on the network and associate resources and users logically. VLANs facilitate grouping of multiple geographical stations as such if the user move to another physical location, the network does not have to be configured.
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