When one or more storage data are coincident with single search data (12),
an associative memory (1) carries out logical sum for all of storage data
with a valid state for storage data as true. The result of logical sum is used
as matched data logical-OR information. In a primary searching operation, the associative
memory (1) is supplied with the search data (12) to provide the matched
data logical-OR information on matched data logical-OR lines. Then, the associative
memory (1) carries out a secondary searching operation supplied as search
data with the matched data logical-OR information obtained by all of storage data
coincident upon the primary searching operation. Only a match line (5) coincident
with the matched data logical-OR information is selected as the secondary search
result. The associative memory is used in a network router to calculate an optimum
memory address signal (403) by encoding the selected match line (5).
In response to the memory address signal (403), a memory data signal (405)
enabling shortest network connection is produced as a transfer network address
(413). The transfer network address (413) is combined with a data
area (412) and a destination network address (411) contained in input
transfer data (408) to produce output transfer data (409).
