Research Of Low-overhead Delay Measurement For Overlay Network

The overlay network is a virtual logical network based on the Internet,it is a kind of widely used network technology.Through overlay network can effectively improve the existing network performance and flexible deployment of new applications.Network delay is an important parameter to realize many function of overlay network,such as overlay routing,content distribution and so on,therefore,the overlay network delay measurement to get the attention of the researchers.Overlay network delay measurement,namely through the network measurement technology to obtain delay information of overlay network paths,the pros and cons of its measurement method is not only related to the efficiency of measurement,but also affects the performance of the network being measured.Along with the overlay network's complexity and degree of openness increasing,there is a common problem in existing overlay network delay measurements methods which is the large overhead.In response to this problem,this paper presents an improved overlay network delay measurement method,the main work is as follows:First,this paper investigates the relative concepts of overlay network measurement intensively,analyzes the characteristics of several typical measurement methods and their main problems.Made clear the importance of overlay network delay measurement,as well as the study of problem and solution.Second,about the large overall overhead problem in current overlay network delay measurement method based on full node measurement model,an improved low overhead measurement method is proposed in this paper.The whole process of this method is based on the non-full-node measurement model,which includes the underlying network structure detection and delay measurement.In the aspect of underlying network structure detection,through detection results exchange between nodes to reduce the number of detection required for obtaining all the target link structure information.In the aspect of delay measurement,this paper considers measurement efficiency and measurement conflict,select part of nodes as the measuring node to measure the delay of paths,and use the delay of underlying network links obtained by layer by layer tomography to calculate the delay of paths which are unable to measure directly by measuring node,effectively decrease the number of delay detection.From the above two aspects reduces the overall overhead of the measurement.Thirdly,this paper uses the NS2 tool to simulate the overlay network of different overlay density,and carry out delay measurement simulation experiment.Through the comparative analysis with the main measurement methods,we verify the improvement of this overlay network delay measurement method in the measurement overhead.