Research On Traffic Conditioning Of Train Control And Service Network

China’s train control network technology and standard have been monopolized by international giants in a long time.The available train control network is physically separated from the passenger service network.The train control and service business are becoming more complex and diverse.For these requirements,the National Support Plan Project(2015BAG14B00)proposes to build a new type of train communication network that is named the Train Control and Service Network(TCSN)to realize the integrated transmission of train control business and service business.The thesis takes the project as a background to study the key technical issues of TCSN traffic conditioning and queue management.Unlike the traditional train communication network that only transmit control business,the TCSN requires train control business and passenger service businesses to be transmitted integratedly in same train communication network.The key control business is to support the safe operation of train,which is tramitted preferentially It has a negative influence on the key control business to transmit service business in same network.TCSN needs to guarantee the priority transmission of control business,and provide a certain degree of quality of service assurance.In addition,control business includes the key control business and non-key control business,and the passenger service business includes a variety of business traffic generated by passengers’ network behavior in the train operating environment.When such a large amount of traffic is transmitted integratedly in the TCSN,it is easy to cause network congestion and is difficult to guarantee the quality of service for each business.Therefore,the TSCN traffic conditioning is one of key problem that must be solved for building the TCSN technology system.The traffic characteristics and transmission requirements characterisitic of control and service business are analyzed based on understanding TCSN and its business classification.The TCSN network uses DiffServ architecture to guarantee QoS,and the Service Level Agreement(SLA)and the Traffic Conditioning Aggrement(TCA)are formulated for the TCSN based on the above characteristics.The method of TCSN traffic conditioning and queue management is given.Then the TCSN traffic conditioning algorithm is designed in detail.The research focus on traffic control mechanism based on token bucket,first-level token allocation algorithm,and excess token quota allocation algorithm of the second-level token allocation and queue mananement algorithm.Finally,the TCSN traffic conditioning and queue management algorithm is simulated.The TCSN traffic conditioning algorithm is firstly simulated independently.The change of allocation quota of redundant tokens verifies the dynamic of traffic conditioning and the feasibility of DiffServ for the algorithm after first-level token allocation and secondary token alloction.Then the traffic conditioning and queue management algorithm is added on TCSN to simulate the whole network.The business traffic model is first abstracted from the traffic characteristic,and the simulation data in accordance with actual situation is generated according to the traffic model.The TCSN is simulated based on business and discete event simulation method to verify the TCSN system performance of different traffic conditioning and queue management algorithm,the real-time and reliability of the TCSN traffic conditioning algorithm.