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A Critical Note On Ring Flushing
Syed Muhammad Atif
Pages - 87 - 102     |    Revised - 01-05-2011     |    Published - 31-05-2011
Volume - 3   Issue - 2    |    Publication Date - May / June 2011  Table of Contents
Ring Flushing, Frame Flooding, Network Scalability, RSTP Compatibility
Rapid Spanning Tree Protocol enable switches to flood incoming frame with broadcast or unknown unicast destination address even in switched Ethernet networks having redundant links. It also allows switches to secretly learn location of connected devices in such networks. However some of those learnt location may become stale if a topology change is detected by RSTP and need to be flushed by switches in the network. It is find that standard address flushing technique of RSTP flushes too many addresses from large number of switches after a topology change. As a result there is a sudden massive increase in flooding traffic which may cause network-wide congestion, frame delay and frame loss. Recently a new address flushing technique named as Ring Flushing was proposed for RSTP that flushes addresses from small number of selective ports of very selective switches and so dramatically reduces the amount of flooding traffic after a topology change. However, number of flaws are identified in the current implementation of this newly proposed technique. This paper will not critically discuss the flaws in the current implementation of Ring Flushing but will also propose there simple yet effective solutions.
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Mr. Syed Muhammad Atif
Mega In - Pakistan