Patent ID: 7397816

Claim:
A relay device using the Direct Memory Access method comprising: a main control unit; and an external interface unit being configured to receive receiving data from outside, said external interface being configured to transmit directly said receiving data to a corresponding destination memory independent of said main control unit, said external interface unit comprising, a memory unit being configured to store said receiving data as stored data in descending order said receiving data, a threshold setting unit being configured to set a threshold corresponding to a quantity of said stored data, and a control unit being configured to send a predetermined reaching threshold notice to said main control unit upon a data quantity of said stored data reaching a predetermined threshold, said main control unit being configured to delete said receiving data judged as deletion data being unnecessary upon judging whether said receiving data unnecessary to be transmitted to said corresponding destination memory upon said main control unit receiving said reaching threshold notice and reading corresponding information of a field of said stored data stored.