Looking Beyond the First Moment: Analysis of Packet-related Distributions in P4 Systems with Controller Feedback

The ubiquitous spread of programmable data planes has been conditioned by the development and use of domain specific languages. One such very convenient programming language is P4, which enables devices, like switches, to be configurable and protocol-independent, making it a perfect match for Software Defined Networks. Therefore, analyzing the metrics of interest in such a network is of paramount importance to understand what actually happens in the system. However, while previously there were studies dealing with performance analysis on P4-enabled systems, these were mostly bounded to obtaining the first moment of the metrics of interest. This does not provide a full picture of how P4-programmable switches operate. Hence, in this paper, we provide an analysis of the distributions of the metrics of interest in the system, modeling its behavior as a queueing network. We provide arguments as to why a normal distribution can mimic the service time distribution of the data plane. We consider the behavior under different distributions of the service times in the control plane. Results show that the variance of the sojourn time tends to decrease when a higher number of packets is sent back to the controller, which is more emphasized with the medium-rate and slow controllers, where the coefficient of variation can be reduced by at least 35%.      «

The ubiquitous spread of programmable data planes has been conditioned by the development and use of domain specific languages. One such very convenient programming language is P4, which enables devices, like switches, to be configurable and protocol-independent, making it a perfect match for Software Defined Networks. Therefore, analyzing the metrics of interest in such a network is of paramount importance to understand what actually happens in the system. However, while previously there were s...     »