Jin Yuehui

SCTP simulation on NS

The stream control transmission protocol (SCTP) is a new protocol applied on the transport layer, which is proposed by the IETF in RFC2960. SCTP has some new features compared with the traditional TCP transport layer protocol. As a promising new protocol, it may be used on traditional IP networks, mobile IP networks, and carry on some traditional application, such as FTP, HTTP, and some undiscovered ones. In order to evaluate its performance, our group has been working on the simulation of SCTP on a simulating software, network simulator (NS).

Protocol conformance test suite generation

The strategy of generating test suite from protocols modelled EFSM is presented. The concept of transition/program dependency graph (TPDG) constructed from data flow of EFSM is presented. From the TPDG and the control flow graph (CFG) of EFSM, test sequences that can test both the control part and the data part can be generated. Test data (for parameterizing test sequences) selection method is discussed too. The generated test cases (parameterized test sequences) are described in TTCN according to ISO/IEC 9646. A software-test suite generation system (TSGS) based on the above strategy is introduced. The software is implemented in a Sun sparc station.

Border collision bifurcation and chaotic control of discrete feedback transmission control protocol-random early detection system

Various types of border collision bifurcations occurring in a discrete feedback transmission control protocol-random early detection （TCP-RED） system are analyzed based on normal form method. As the system parameters change, the system experiences the border collision and a sudden jump from a periodic attractor to a chaotic attractor leading to the intense vibration of the system and serious degradation of its performance. According to the linear stability condition of fixed point, a method of chaotic control is presented. With this method, the system can be stabilized to the fixed point by perturbing the state variable in the neighborhood of the fixed point. This method can significantly improve the performance and the resource utilization of TCP-RED system, and simulation results show that it is effective.