Research And Implementation Of The Component-Based TCP/IP Protocol Stack In Embedded Linux

Currently, most embedded equipments have the characteristic of the small storage capacity, the slower processing speed and the sole network application. There are some problems when applying traditional monolithic network protocol stack to these embedded system. The first one is if some protocol's function need be updated, must update the entire protocol stack even recompile the kernel. The work is complex. The second one is that the protocol stack is not flexible, one cannot configure protocol according to the actual network demand of embedded system. The resolvation of these two problems is important to improve protocol stack development, updating and the implement configurable protocol stack.To resolve above two problems, this paper introduces the component-based software development to the protocol stack transformation. Firstly, it designs a protocol stack component framework, and proposes the characteristic of this framework and designing principle. This frame is mainly composed of protocol components, the components repertory, the components development platform and the componentized operating system. The protocol's developer can get the whole understanding of the system, and will greatly improve the efficiency of protocol stack development and updating through the research of protocol stack component framework.Secondly this paper discusses the dividing principle of granularity. To the characteristic of the protocol stack in Linux, the paper proposes two kinds of feasible dividing method, such as sub-protocol components and application objects components. Component granularity is most heavy according to sub-protocol between them, but it is advantageous to assemble and manage the components;The granularity is best according to the application objectcomponents, but the work of splitting and assembling components is relatively complex.Finally, this paper implements the sub-protocol components by Linuxmodule mechanism. The result indicates that although the performance of the network slightly drops after the protocol componentized, but can reduce the size of kernel, accelerate development and upgrading course of the protocol stack, and the achievement can be used for the embedded system that has not high expectations for performance of the network.