Estimation of the explicit cell rate for the ABR service based on the measurements

The ATM Forum has defined two modes of operation for the ABR (available bit rat) congestion control algorithm, i.e. the explicit rate indication (ERI) and the binary congestion indication (BCI). As the standardization process is mainly focused on the UNI interface, the switch mechanisms are left to the vendors. The objective of the ERI algorithm is to determine the actual explicit rate while the BCI algorithm uses queue thresholds to detect congestion and noncongestion state. This information is sent to the source in order to update the allowed cell rate. In this paper we present a method to implement the ERI algorithm based on the measurements of spare link capacity. To illustrate the effectiveness of the proposition, several numerical results are included. Finally, the method is compared with the standard BCI algorithm