Interoperability of EFCI and ER switches for ABR services in ATM networks

With the advances in switching technologies, explicit rate (ER) switches are becoming popular since they perform better than explicit forward congestion indication (EFCI) switches. In the transitional period, EFCI and ER switches may coexist in the same ATM network. Hence, the efficiency of various ER schemes should be reevaluated in the mixed EFCI-ER environment, not only in the homogeneous ER environment. Also, some important implications are observed in the heterogeneous environments. Because the location of an ER switch in the topology is critical to its performance, some placement rules, which describe how to place the ER switches for network operators, are developed in order to achieve a better performance of the network. The results presented should serve as an operational reference for service providers.