The Study And Implementation Of Light-weight TCP/IP Stack For Embedded Internet

Embedded Internet has become a new milestone in the process of Internet development. For the limitation of computation and memory resources in embedded system, embedded Internet can be classified into two architectures: Gateway-based architecture and Direct-connection architecture.Compared to Gateway-based architecture, Direct-connection architecture is a new architecture and has more applied prospect for the reason of its advantage in low system cost,open and portable characters.The key answer to the problem of implementing Direct-connection embedded Internet architecture is to simplify full TCP/IP stack based on specific Internet application and software-hardware system circumstance of embedded system with limited system resources. We call this type of tailored TCP/IP stack light-weight TCP/IP stack. Current researchs on light-weight TCP/IP stack have many shortages that either brings out duplicate work because of mixing the design and implement of light-weight TCP/IP stack with embedded Internet application or has no characters of configurable, portable and simple interface specification and so on.First, we study the methods of simplifying full TCP/IP stack to implement light-weight TCP/IP stack. Then, a new light-weight TCP/IP stack is designed and implemented, which called emIP(embedded IP)stack.emIP stack uses an event based programming model where the application (protocol) is implemented as a callback function that is called by emIP in response to certain events such as new data is received,which resolves the problem of separating TCP/IP stack from implementation of embedded Internet application.As for configurable character,emIP stack not only implements the modules of various protocol but also makes the implementation of protocol configurable,which will greatly low the comsumption of system resources in embedded system.As for portable character,emIP stack abstracts the related characters of embedded design platform frequent used for easy modification using a C header file.As for easy usage,emIP stack affords simple basic network interface with function library.At the end, a simple embedded web server as a testing case using network interface afforded by emIP stack is implemented. Also, this simple embedded webserver is tested on an 8-bit embedded system platform-EWEB designed and implemented by us. From the testing result, we draw conclusion that emIP stack have configurable, portable charaters and also have characters of limited system resources Consumption, simple and easy interface specification and so on.