A New Consolidation Algorithm for Point–to–Multipoint ABR Service in ATM Networks

Abstract

In ATM networks, ‘feedback implosion’ may occur at the source of a point-to-multipoint Available Bit Rate (ABR) service if the Backward Resource Management (BRM) cells are not consolidated at the branch-points. Existing consolidation algorithms do not consider information contents of a BRM cell to decide whether the cell should be passed to the upstream node or not, and they suffer from various undesirable effects, such as consolidation noise, slow transient response etc. In this paper, first we clearly identify the responsibilities of a branch-point of a point-to-multipoint ATM ABR connection, and then we propose a new consolidation algorithm where a BRM cell is passed to the upstream node immediately if it contains ‘critical information’, otherwise, it is discarded. We investigate the performance of our algorithm using simulation, and the results show that our proposed algorithm provides faster and more accurate feedback with excellent scalability, in comparison to the existing waitfor- all algorithm.