Analysis of Load-Balanced Switch with Finite Buffers

Recently the Birkhoff-von Neumann load-balanced (LB) switch has become a promising switch design due to its high scalability properties and simple control. The performance of the LB switch was studied under strong assumptions such as infinite buffers and admissible traffic conditions. However, both such assumptions may be violated in multi-hop networks since admissibility requirement cannot be maintained unless some inter-switch feedback mechanism is implemented, and infinite buffers are not feasible either. This paper considers the performance of the LB switch with finite central stage buffers under both (i) admissible and (ii) inadmissible input traffic conditions. Its contributions are two folds: firstly, by means of mathematical model we demonstrate that the load-balanced switch has a non-zero cell dropping probability due to buffer overflow even under the admissible input traffic assumptions. Secondly, cell loss probabilities are even higher and large buffers are required under inadmissible traffic conditions to cope with such behavior.