The network switch or switch (from engl. switch — the switch) — the device intended for connection of several nodes of a computer network within one segment. Unlike the hub which extends traffic from one attached device to all rest the switch transfers data only directly to the receiver, the exception makes the broadcast traffic (to the MAC address FF: FF: FF: FF: FF: FF) to all nodes of network. It increases performance and security of network, saving other network segments from need (and opportunities) to process data which to them did not intend. The switch works at the data link layer of the OSI model and therefore generally can only integrate nodes of one network to their MAC addresses. Switches were developed using bridge technologies and often are considered as multiport bridges. For connection of several networks on the basis of the network layer routers serve.