Energy-efficient non-volatile TCAM search engine design using priority-decision in memory technology for DPI

Abstract

TCAM-based search engines are widely used in regular expression matching across multiple packets. However, the use of priority encoder results in increased energy consumption of pattern updates and search operations. This work, proposes a promising memory technology, called Priority-Decision in Memory (PDM), which eliminates the need for priority encoders and removes restrictions on ordering, meaning that patterns can be stored in an arbitrary order without sorting their lengths. Moreover, we present a Sequential Input-State Search (SIS) scheme to disable the mass of redundant search operations in state segments, based on the analysis distribution of hex signatures in a virus database. Experimental results demonstrate that PDM-based technology can improve update energy consumption of nvTCAM search engines by 36%~67% because most of the energy in the latter is used to reorder. By adopting the SIS-based method to avoid unnecessarily search operations in a TCAM array, the search energy reduction is around 64% of nvTCAM search engines.

NVSim-CAM

“…The priority encoder only generates the lowest address of all the matching entries. The encoder is implemented to facilitate particular applications [25] or to reduce global wiring for the results. The priority encoder is made of a multiple match resolver (MMR) block and a normal encoder block.…”