On the Effect of Scale-Free Structure of Network Topology on TCP Performance

In recent years, it has been reported that several existing networks represented by the Internet have scale-free structure. In this paper, through simulation experiments, we investigate the effect of the scale-free structure of communication networks on the end-to-end performance of TCP flows. As a network topology, a random network and a scale-free network with the equal number of nodes and the equal number of links are used. We compare the end-to-end performance of TCP flows (i.e., throughput, round-trip time, and packet loss rate) in a random network and a scale-free network. Consequently, we show that the scale-free structure of a network has positive effect on the round-trip time of TCP flows regardless of the number of nodes and the average degree of a network. We also show that the scale-free structure of a network has negative effect on the throughput and the packet loss rate of TCP flows when the average degree of a network is small.