Research And Implementation Of Data Capture In High-speed Network Environment

In recent years, the Internet and communication technology has been a rapid development and the data traffic in the network has also been rapid growth, which makes various network infrastructure and applications based on data-capture are suffering a serious challenge, and some can not be used directly. Therefore, it is not difficult to understand the importance of the research for higher performance and more efficiency capture mechanism.Firstly, this paper makes an intensive study of various traditional packet-capture technics, carries on a detailed analysis to packet-capture principle and the existing problems. Through the study, we found that, in the traditional packet-capture system, there are two data's copy processes in the memory, which cost a huge overhead and always severely affect the performance of the system.Secondly, On the basis of the study mentioned above and the idea of zero-copy, this paper brings out a high performance data capture model based on RTL8169,which makes the data can be directly stored by DMA to the address space where application programmes are able to access. As a result, it avoids the data copy in memory and saves the cost of CPU. Under the study of the key technologies required to implement this mechanism, we gives it a specific implementation.At last, we carried out a detailed performance test to this capture mechanism. The test results show that the highest capture rate of this platform has reached929M when the capture data packet is big, and the performance of the net card has been almost maximized. At the same time the capture rate for small data has also been dramatically increased.