Research And Implementation Of The BFD On Simulation System Based On Distributed Data Communication Equipment

The simulation system which simulates distributed data communication devices is mainly used to simulate the communication net in the real environment.It can not only simulate the transmission process of messages in single equipment,but also simulate the forwarding process of messages between the equipments.The system is based on the Linux operation system,C programming language and Socket programming language,it takes the core control module as the center,and sets up connections with the command shell and simulated devices?TestCenters by the network protocol.Compared with the traditional simulation system,the striking features of this system are that:On one hand,it combines the forwarding plane to simulate the forwarding process,on the basic of supporting the control plane.so,the system can locate the problem of the data flow timely,and solve it as soon as possible.On the other hand,the system also support to simulate the TestCenters.As a result,it reduces the cost of the engineering test,and improves the research efficiency.BFD(Bidirectional Forwarding Detection)provides a detection mechanism,w hich is light load and short hours,to test the connection state of the forwarding path between two routers or switches.It has many unique advantages compare d with the previous “hello” detection mechanism.This paper combines the distributed simulation system and BFD,then simulates the equipments receiving and sending BFD packets,and the whole changing state of the BFD finite state machine,in order to perfect the simulation system and adapt to the complex and changeable market.The main contents are as follows:(1)Introduce the overall struct of the distributed simulation system.Firstly,it introduces the internal architecture of the single equipment,then it has a introduction about the packets' interaction process in single equipment.(2)Introduce the layered structure of the distributed simulation system:core control layer?forwarding layer and so on.(3)Based on this simulation system,it introduces the BFD,and mainly focus on receiving and sending the bfd packets?building the packets and realization of the transimission of the state machine.The innovation points are as follows:(1)It simulates several equipments,and realizes the communication between the equipments and instrucments.(2)Based on the original simulation system,it adds the ability that simulate the FPGA sending BFD packets between two equipments.(3)It can timely send and receive BFD packets,and add the time counter.It realizes that the state machine can change its own state based on different scens.