Context-Free-Grammar based Token Tagger in Reconfigurable Devices

In this paper, we present reconfigurable hardware architecture for detecting semantics of streaming data on 1+ Gbps networks. The design leverages on the characteristics of context-free-grammar (CFG) that allows the computers to understand the semantics of data. Although our parser is not a true CFG parser, we use the linguistic structure defined in the grammars to explore a new way of parsing data using Field Programmable Gate Array (FPGA) hardware. Our system consists of pattern matchers and a syntax detector. The pattern matchers are automatically generated using the grammar token list while the syntax detector is generated based on the aspects of the grammar that define the order of all possible token sequences. Since all the rules are mapped onto the hardware as parallel processing engines, the meaning of each token can be determined by monitoring where it is being processed. Our highly parallel and fine grain pipelined engines can operate at a frequency above 500 MHz. Our initial implementation is XML content-based router for XML remote procedure calls (RPC). The implementation can process the data at 1.57 Gbps on Xilinx VirtexE FPGA and 4.26 Gbps on the Virtex 4 FPGA.