VLANs are like rooms in a home. If you are having a party and everyone is trying to have a conversation in the same room, things will get very loud and information may be lost (performance decreases) in some of those conversations. However if you separate everyone into rooms (VLANs) the volume will lower and conversations become easier (performance increases) to have because you're not hearing everyone else's conversation at once. This also helps keep the conversations a little more private (security) as not every person in the home (LAN) will hear every rooms (VLANs) conversations. This can also help if you wanted to keep the children separated from the adults, you could simply lock the door (separate the VLAN) to the neighboring room and they wouldn't be able to hear the adult's conversation (security). ... View more