Network switch

A Network Switch is a telecommunication device which facilitates communication within networks. It is classified as a layer-two device on the OSI model. It isolates collision domains (each port is a separate collision domain), and uses MAC addresses to communicate. However, broadcasts are not isolated by standard switches, meaning they offer less network security than routers. Some switches can be configured aftermarket with VLANs to serve this function, but it is not a default function. (This requires a layer 3 switch to enable the VLANs to communicate.)