Transparent interconnection of incompatible local area networks using bridges

No single LAN (local area network) technology is sufficient to interconnect all the computers in a given plant, campus, or site. Thus, it is desirable to combine different types of LANs, using a device called a bridge, to produce an extended LAN. Bridges learn their routing information from information contained in frames they forward. Besides the problems of distinguishing various kinds of encapsulated and unencapsulated frames, the encapsulating protocol used by bridges must also solve the learning problem. This leads to a new set of considerations and solutions. The authors begin with a rough solution and refine it using informal arguments and examples to lead to the final description. The stages in the description roughly mimic the design process. The protocol achieved offers generality and correctness, efficiency, compatibility, and extensibility and requires minimal storage