A local bridge can segment a LAN to reduce bottlenecks and reduce collisions. The function of a remote bridge is sometimes performed by a Router. A parallel looping bridge - this provides redundancy. But the problem is that a node can generate packets on both networks and these can loop forever. A root bridge is identified, and all other bridges find a low cost path to span the network.
Bridges also block connection ports in one direction to prevent looping.
Router A router filters and forwards packets from one network to another. It will examine and change network headers, DLC layer headers and MAC protocol headers. They operate at Layer 3 of the OSI protocol and do not assume that the underlying networks are LANs. Routers connect networks that have dissimilar data link layers and network layers, e.g. a LAN and a packet switched network and a circuit switched network. Operation of a router Consider a packet being routed from a CSMA CD LAN to a packet switched network.