Effects of excessive frame loss on scanning tree reconfiguration

Abstract

The effects of excessive frame loss (presumably due to media speed mismatches and/or heavy congestion) on the frequency of spanning tree reconfiguration are examined. Assuming that the losses of successive bridge protocol data units (BPDUs) are independent, general formulas for the mean time and transient probability of a single node initiating spanning tree reconfiguration (due to loss of successive BPDUs) are derived as a function of its probability of frame loss. The case of n equivalently independent nodes in the network is considered. The mean time to first loss (conditioned and unconditioned on the initial state of the system) given a step increase in utilization to above 1, if the node is modeled as an M/M/1/K system, is determined. Throughout, methods for making the network less susceptible to unnecessary spanning tree reconfiguration are discussed.<>