REGULAR EXPRESSION REPRESENTING METHOD FOR EFFICIENT PATTERN MATCHING IN TCAM AND PATTERN MATCHING METHOD

A method for representing a regular expression in a TCAM(Ternary Content Addressable Memory) for efficient pattern search and a pattern searching method using the same are provided to improve search performance by efficiently describing representation for character classes/repetition of the regular expression difficult to be represented in the TCAM and reducing a search frequency of the TCAM. A previous identifier for starting of a pattern is inserted into a front side of an entry and is searched from the TCAM. If the matched TCAM is present, TCAM-related data corresponding to the entry is read and the next identifier is checked. If the pattern is continued, a remained quantity is calculated by using a difference between a repeated quantity and a movement value, a search position is adjusted to a right side as much as the movement value, and the next identifier is replaced with the previous identifier of a next search target. In case of an end of the pattern, match is finally checked by checking whether the search position is within a repeated range or not by checking whether a minimum number among the remained quantity is equal or smaller than zero, or the maximum number is equal or bigger than zero.