Modeling And Analysis Of Few Files Parallel Transmission Problems Based On Petri Nets

Formal software developing is the primary means for large scale software development.It promotes the software robustness with the formal software technology, reduces a lot oferror and saves the cost. Through verification and analysis, vague and incomplete propertiescan be found, which improving more efficient on software quality and model progress.Formulation is divided in two parts: formal specification and formal verification. Petri net is aperfect description tool satisfied the two demands.Concurrency is the main feature of network environment. It means asynchronous, orderand disorder. Petri net is a tool of description and analysis concurrency. It holds the analyticalability for the model structure and dynamic behavior. The resulting can be used to promotesystem. At the same time, a bridge built by Petri Nets provided a communication environmentfor the programmers and developers.In the environment of network, the system is receiving users’ various operationrequirements all the time. But the system could process all the operations by sequence. It’spreferably to use a concurrent form to process the request. Then it can maximize cyber sourceutilization rate, and meet people’s demands and wishes.There are many factors affecting the transmission efficiency of network, such as thesystem may be unable to handle all operation requests in time. A very important reasoncausing resource waiting is competitive resource, which means: in a certain period, all theresources have been occupied; or the operation application hasn’t arrived to the destination; orthe response request is still in the road and so on. So it is necessary to process the operationrequests asynchronous.The main work of this paper is as follows:(1) Construct a conflict-free parallel files transmission model based on Extended Petrinets. Simulate the whole file transfer process combining with the time control subsystem.Meanwhile, use S-Invariants analyzing some dynamic behaviors of the model, and validatesthe reasonable and accuracy of the model.(2) Using the approach of data exchange network send and receiver files. And there is nodirect relationship between receivers and senders. It avoids waiting caused by each of themhas no transmission resources At the same time, introducing the concepts of time and color,use the hierarchical method to construct parallel transmission of files model based onextended colored Petri nets. It reduces data transmission time, improve the networkcommunication performance. Meanwhile use S-Invariants to analyze and validate the model.And simulate the model using CPN tools.