The Research Of Delay Problem In Embedded High-Loading Network Communication

Embedded system has been introduced into more and more application areas for its inherent characteristics such as high reliability, small cubage and low costs nowadays. New generation of embedded system mostly features at functionality integration and embedded network computing, which promotes more attention and interesting into real-time network communication between embedded systems.But now the MAC layer use the Ethernet based on IEEE802.3 criterion, which adopt CSMA/CD to listen the occupied time of channels ,when listening the free time of channels, the system will transmit data. or if listening the collision ,it will give up sending the data, at the same it will delay a stochastic time and begin to listen again.As a result, it will cause an uncertain time delay which become an important problem in real-time communication areas. Especially for high-loading network communication, the delay will become more and more longer. The task of this thesis is required to reduce the delay which CSMA/CD causes so as to improve the real-time of high-loading network communication in embedded computing environment.In order to solve this problem, a new software resolvent based on a kind of protocol at transport layer called Embedded Real-Time Communication (ERTC) is brought forward in this paper.The protocol take full use of the free of Linux codes and the compatibility for TCP/IP. We divide into two kinds of network nodes which one is one Communication Controller (CC) and others are Remote Terminal (RT) in a special LAN composed of embedded devices.CC adopt a table of centralized poll to control the network communication of RT in the LAN.At last, in order to validate ERTC's validity,we test and compare for the End To End (ETE) delay of TCP/UDP and ERTC.The test results show ERTC reduced the delay which CSMA/CD causes, to some extent, ERTC increased the real-time of high-loading...