MTU configuration for real-time switched Ethernet networks

Abstract

We motivate and formulate the effect of MTU size configuration on the response time of messages crossing through a HaRTES architecture.We propose a search-based approach, with two techniques to reduce the search space, to find the optimum MTU size.We propose a heuristic algorithm with pseudo polynomial time complexity to find the best MTU targeting a shorter response time for messages.We experimentally show that the heuristic algorithm finds MTU sizes such that the response time of messages is improved around 30 %.We experimentally show that the heuristic algorithm performs as good as the search-based algorithm as a reference. In this paper, we show that in real-time switched Ethernet networks reducing the Maximum Transmission Unit (MTU) size may cause an increase or decrease in the response time of messages. This contradicting behavior arises an optimization problem for configuring the MTU size. We formulate the optimization problem in the context of the multi-hop HaRTES architecture, which is a hard real-time Ethernet protocol. As part of the solution, we propose a search-based algorithm to achieve optimum solutions. We modify the algorithm by presenting two techniques to reduce the search space. Then, we propose a heuristic algorithm with a pseudo-polynomial time complexity based on the search-based algorithm. We perform several experiments, and we show that the proposed heuristic results in an improvement regarding messages response times, compared with configuring the MTU to the maximum or minimum values. Moreover, we show in small network configurations that the heuristic performs as good as the search-based algorithm in many cases.