The Research And Implementation For The Matching System Of Regular Expression In Bgp Protocol

Regular expression is a hot technology of character matching and applied in BGP. The content of this paper is how to improve the efficiency of the matching of the regular expression. In BGP, the regular expression is implemented by software and used to filter routing information. But much routing transaction and its efficiency influence the efficiency of the BGP a lot. Therefore,how to improve its efficiency is the key point and this project is designed for this demand.After the research of implementing method of regular expression at home and abroad, this paper brings forward a new technology to implement the matching of the regular expression. With the application background of routing protocol, it runs on embedded platform and uses the algorithm of POSIX library of regular expression. Through combining software's flexibility and hardware's high speed, the embedded Linux system and FPGA work together to accelerate the matching of the regular expression.In specific implementation, the system is divided into a module of software system, a module of hardware system and communication interface. Firstly, a regular expression and a string are inputted into the module of software system. It runs on embedded Linux system and uses stack to compile the regular expression into implementation codes which can be read and implemented by computer, and generates the data of fastmap. Because the module of software system and the module of hardware system run on different platforms whose speed are also different, the communication interface is charged of communicating between them. The module of hardware system runs on FPGA. With the implementation codes, string and fastmap data, it uses stack to finish the calculation of the matching of the regular expression and gets result. In the whole design, there are some special features such as"hardware acceleration","the principle of shortest match"and"giving up the calculation of matching details". The system operates efficiently and finishes the design task well. In the end, the paper gives the testing result including logicality and efficiency. It proves that the system has correct logicality and good acceleration effect. In conclusion, the design is successful.There is some innovation and contributions in this design. Firstly,based on that many matching methods of regular expression are analyzed,a new method combining software and hardware platform is designed. Secondly, the new design is implemented on embedded platform to improve the matching of the regular expression. It supports the embedded device such as router well and has a lot of values.