A broadcast domain is the portion of a computer network that is reachable by a broadcast. A broadcast is the transmission of a message to all hosts (i.e., computers) on the network or part thereof (i.e., network segment) simultaneously. In contrast to a collision domain, which is determined at the data link layer (the second layer of the OSI reference model) and is typically confined to a network segment in a LAN (local area network), a broadcast can be initiated at any of several layers, and it thus can be either confined to a single segment or routed across multiple segments. Created October 6, 2005. |