Design And Implementation Of Terabit Router Embedded Realtime Operating System

Operating system is the important part of Terabit router software, which performance is the dominating factor of the whole software system. This paper studies the design of embedded realtime OS in Terabit router. Based on the requirements of Terabit router, it puts forward that the embedded realtime OS in Terabit router should be developed based on Linux. It analyzes deeply the dominating factors that have an impact on the Linux realtime performace and the current solving schemes, and brings forward the design of embedded realtime Linux OS in Terabit router. This paper also puts the schemes into reality and gives the test results. The results show that the realtime performace of the subsequent kernel is superior to the original kernel and can meet the requirements of Terabit router. The main work can be outlined as following:This paper summarizes the basic concepts of embedded realtime OS, analysizes the security, continuity and realtime performace that the Terabit router requires. Because commercial embedded realtime OS cann't satisfy the requirements, it puts forward that the Terabit router1 embedded realtime OS should be developed on the basic of Linux OS.This paper analyzes the response characteristic of Linux, indicates that the realtime performance of Linux OS can't meet the requirements of Terabit router. It summarizes the main factors that have an impact on the realtime performance of Linux, which include interrupt mechanism, preemption mechanism and scheduling mechanism. After that, this paper studies the schemes used by the leading embedded realtime Linux, including dual-kernel scheme, adding preemption points to the kernel and the scheduling structure based on realtime scheduling policies.Based on the above schemes, this paper proposes the design of embedded realtime Linux OS used in Terabit router, which combines low-latency scheme with preemption scheme to solve the non-preemptive kernel and replace the single running queue with multiple running queues in order to reduce the delay of scheduling.Finally, it puts the schemes into reality and tests the performance. The results show that the subsequent kernel indeed improves the delay of task response time. And it can satisfy the requirements of Terabit router.