A STREAMS based high performance IP/X.25 router

IP/X.25 router is a principle approach to realize the interconnection between two TCP/IP networks over X.25 network. In this paper, the design and implementation of a STREAMS based high performance IP/X25 router is discussed. We first discuss the method for developing communication software in a UNIX kernel, and define a basic abstract model for it. This method will improve the performance of communication software and device driver. After a brief introduction of the function of IP/X.25 router we present the structure of a high performance IP/X.25 router which is designed and realized with that model in UNIX kernel based on STREAMS mechanism. A kind of general finite state machine (FSM) for the connectless internetworking over connection oriented subnetwork service and a dynamic addressing mapping algorithm is described. Finally, we introduce its application in TCP/IP network as a example and discuss the importance of interoperability testing, which could solve the interoperable problem of communication software.