Address filter unit for carrying out address filter processing among

Abstract

The present invention relates to an address filter method and unit to be used in a bridge unit or the like for connecting networks. The address filter unit carries out an address filter processing between a plurality of networks by using address information extracted from an incoming information frame registered in an entry table. In order to improve the processing efficiency of the address filter processing, the address filter unit includes timers corresponding to each address information registration, timer updating means for sequentially and intermittently advancing each timer value, and means for deleting registration of the address information corresponding to the timers from the entry table when a timer value becomes equal to or above a predetermined value. Further, the address filtering method includes a first step for sequentially generating, as an address of the entry table, a function (fi(a), i=1 to n) of a source address extracted from an incoming information frame at the time of a registration in the entry table or a destination address (a) extracted from an incoming information frame at the time of a retrieval from the entry table, a second step for deciding whether or not address information can be registered in an address generated in the first step in the entry table, at the time of registration, and a third step for deciding whether or not address information registered in an address generated in the first step in the entry table is desired address information, at the time of retrieval.