In network communications, there are two devices that keep thenetwork operating: a bridge and a router. A bridge is a device thatuses a technique called bridging. In a packet-switched network,which is the only kind of network bridges operate in, data is sentfrom computer to computer in discrete blocks, called packets. Abridge locates the computer a packet is meant to be sent to bybridging all the network connections at once. The bridge thenstores the computer’s MAC address, which is the address of thecomputer’s network card, in a database that it can access if itneeds to send that computer a packet again.A router forwards data between computers that are not directlyconnected in a network. In other words, routers send data betweencomputers that are in separate networks. Using a tool called