Phenomenon of Higher Order Head-of-Line Blocking in Multistage Interconnection Networks under Nonuniform Traffic Patterns

Nonuniform traffic can degrade the overall performance of multistage interconnection networks substantially. In this paper, this performance degradation is traced back to blocking effects that are not present under uniform traffic patterns within a network. This blocking phenomenon is not mentioned in the literature and is termed higher order Head-of-Line-blocking (HOLk-blocking) in this paper. Methods to determine the HOL-blocking order of multistage networks in order to classify the networks are presented. The performance of networks under hot-spot traffic as a function of their HOL-blocking characteristics is studied by simulation. It is shown that network bandwidth and packet delay improve under nonuniform traffics with increasing HOL-blocking order of a network.