In contrast to routing, bridging makes no assumptions about the location of any particular address in the network. Rather, it utilizes broadcasting to locate devices. Broadcasting is the transmission of a single message to all hosts (i.e., computers on the network) simultaneously. After a device has been located, its location is recorded in order to eliminate the need for further broadcasting.
The use of bridging is limited mainly to LANs (local area networks) because of its reliance on broadcasting. The problem with broadcasting is its overhead (i.e., consumption of bandwidth), which can become very large for large networks and sometimes lead to broadcast storms. A broadcast storm is the situation in which messages broadcast on a network cause multiple hosts to respond simultaneously by broadcasting their own messages, which, in turn, prompts further messages to be broadcast, and so on.
Created November 17, 2005.