Infineon Technologies Ag

Admtek Incorporated

Fang-Cheng Liu

Ding-jyan Syu

The present invention provides a method and apparatus for network address translation (NAT) based on pure hardware architecture. The method includes that when receiving a packet, the first MAC circuit will translate the address of the packet directly and store the address-translated packet into the storage, and that the first MAC circuit informs the second MAC circuit to access the address-translated packets from the storage so as to output. Because address translation requires lots of operating resource, the present invention using the first and the second MAC circuits instead of the CPU to obtain the aforesaid functions only needs a simple, low-speed and low-power CPU to setup the parameters of the first and the second MAC circuits or process few special packets, thus getting the biggest bandwidth under the restriction, the zero wastage of the smallest packet, followed the stipulation of IEEE802.3 in the environment of 100 MHz Ethernet.

Method and apparatus for network address translation based on pure hardware architecture

Current applications used in security system for encryption/decryption/authentication require intense CPU computation for an SAD search. Therefore, a part of the SAD is planted into an ASIC in order to lessen the load of the CPU. The invention provides a high-performance lookup method that is 'LIFM' adapted to the ASIC. Initially, the ASIC makes a perfect match by comparing the SAD_index field of all items allocated in the ASIC with an incoming packet to fetch the required SAD_key. If there is no match, the software and hardware are started by issuing an interrupt from the ASIC until the CPU finds a perfectly matched item. Then, the software level updates the perfectly matched item in the ASIC.

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Hsinchu, Taiwan

Fang-Cheng Liu