vlans are a collection of users or ports grouped together in a secure, autonomous broadcast and multicast domain. membership to a vlan is not restricted by a physical location and can be defined across multiple lan switches.

    port-based vlans allow a network to be segmented in order to reduce the size of broadcast domains. all packets entering a vlan will only be forwarded to the ports that are members of that vlan. this even includes multicast frames and unknown unicast frames.

    another benefit of vlans is that you can change the network topology without physically moving stations or changing cable connections. stations can be 'moved' simply by changing vlan settings from one vlan (the sales vlan, for example) to another vlan (the marketing vlan). this allows vlans to accommodate network moves, changes and additions with the utmost flexibility.

    vlans can also provide a level of security to your network. port-based vlans allow you to configure ports to not accept packets from outside of the vlan.