Network Embedded System Communication Mechanism Analysis And Improvement

With the development of embedded application, the progress of computer and communication technology, and the extensive use of Internet, network connectivity is obligatory requirement of embedded systems. It is important practical significance to research networked embedded systems.Gateway-based and RTOS-based embedded systems that connect to Internet are presented in the paper, we compare the difference of the two schemes, analyze EMIT instance and VxWorks instance , and expound characteristic and requirement of networked embedded system application.Based on analyzing TCP/IP architecture and Socket programming interface, and of Linux TCP/IP suites implementation , we mend the implementation to fit the requirement of embedded application. 1) we modify the "allocate-use-release" use mode of protocol buffer, create communicat ion area of combined with static and dynamic allocation, and adopt efficient "apply-use-return" memory use mode. 2) in order to reduce memory access times,copy data and compute checksum synchronously to fit the requirement of TCP error control. Therefore, it can reduce one time data handling, 3) divide application data into blocks that content the demand of effective load of communication subnet MTU to avoid IP fragments.Embedded performance test code is applied among protocol code by this paper .It can lower test overhead .The client/server test structure is employed that the server test program answers for computing performance data and visually displaying the result. It is proved that the modification of the above can improve the performance of TCP/IP protocol, when sending 1024 bytes application data.it can improves 12.66% performance.