The Design And Implementation Of TOE Architecture

With the enlargement of the network size and sharp increase of the network traffic, the network bandwidth is higher and higher and only high bandwidth network can meet the need for ever increasing information flow. All the time, TCP/IP is all realized inside the host operating system, With the rapid growth of the bandwidth of the network,greater and greater the host computer CPU performance were consumed. The expenses of dealing with TCP protocol suite have already become the bottleneck in whole performance of the host computer. In order to solve this problem, researchers have investigated various optimization techniques for TCP/IP, including high speed TCP algorithm. Applicable to the TOE (TCP Offload Engine) Gigabit network products has been put on the market, such as the Intel PRO/1000, etc. The purpose of TCP/IP offload is to solve the communication processing bottleneck of servers. Its basic idea is to offload TCP/IP processing by moving the processing to hardware devices like FPGA or ASIC. This will free the CPU and improve the network performance and the efficiency of the host CPU. The hardware with TCP/IP functions is commonly called offload engine.Firstly, this paper introduces the basic principle of TOE, offloading the processing of TCP/IP from the host processor to the hardware on the adapter. Full offload and partial offload are two modes of protocol offload. A TOE implementation consists of hardware, ASICs or FPGA, And the TOE software can be implemented as two ways, High Performance Sockets and TCP/IP Stack Replacing.Secondly, after analyzing the basic idea and the principle of TOE, TCP/IP protocol offload technology is investigated for the open source operating system Linux. An architecture for TCP/IP Offloading is defined and a solution for the interface between the server and the offload engine is discussed. An implementation strategy is proposed to connect the two entities. The TCP/IP protocols in the offload engine will take over the network data processing after the original TCP/IP protocols in the Linux kernel are disabled.Thirdly, the paper also studies LKM (Loadable Kernel Module) to proposes some advices on how to implement TOE. The LKM mechanism enabled Linux operating system kernel running on the functions of the state will be able to expand. Experimental test results show that the definition of the offload engine architecture is reasonable, offload engines to connect with the server operating system interface between the solutions is feasible.Finally, take the design of a web server system which is based on TOE Fiscal Cash Register as an example to introduce TOE network interface card applications.