Design And Implementation Of Traffic Replay System

As a method of generating traffic in a network range,traffic replay has the characteristics of irreplaceable.It can ensure that the flow of playback has the same feature with the real network,which is not available in other methods.At present,the existing traffic replay methods are mostly to create a large number of traffic in the unit time,which neglects the time’s authenticity of playback flow.In order to generate the network traffic which is exactly the same as the real traffic in the target network,including packet’s numbers,payloads,interactive orders and time series,this paper proposes a traffic replay method based on packet’s interactive orders and timestamp with multiple machines.And the specific researches are as follows:Firstly,this paper optimizes the existing traffic collection method,and proposes an acquisition method based on multi-point.This method divides the real network into multiple collection points,and records traffic at each point.And this method does not miss traffic from the hosts in the LAN as the existing methods,thus the integrity of the collected traffic is improved.In addition,this paper applies the zerocopy technique to traffic acquisition,improves the capture efficiency of network card,which reduces the packet loss caused by the performance of the network card,ensuring that the playback traffic is more similar to the original network.Secondly,a data processing measure is designed for the multi-point acquisition,this measure includes de-duplication method which based on prefix tree and repairation method which based on contextual relationship.The data de-duplication method optimizes the prefix tree structure to make it more suitable for the deduplication operation of flow stream.The repairation is according by the relationship between sequence number and acknowledge number of the packets sent by both parties to repair traffic.In this paper,the two methods were experimentally tested and results show that the method can do the de-emphasis and repair operation.Then,we optimize the existing replay algorithm and propose a multi-machine interactive playback algorithm,which based on packet’s interactive sequence and timestamp.Compared with the existing algorithms,the experimental results show that when the playback packets is 18000,this algorithm is 1/20 of the existing algorithm in the message transmission time error,and the proposed algorithm does not increase the error due to the increase in the number of playback packets,the existing algorithm does not have this feature.In addition,this paper also carries on the realistic experiment to the algorithm in terms of bandwidth and network flow rate.Only four data points in 129 second playback time have the error,the precision rate is 3%,which is enough to show that the traffic produced by this algorithm is very similar with original flow.Finally,on the basis of the above research,a prototype system of network traffic playback is designed and implemented.And test results shows that this system can take up little machine resources to collect traffic and process data with the user configuration,and then according to the input traffic file,this system can generate traffic in the target network which is very similar to original flow,and experimental personnel can carry out experiments and research in this replayed network.