Enhancing ABR through an improved control infrastructure

The ATM's success in the high speed networking field depends to a great extent on the performance of its ABR (available bit rate) traffic class. ABR allows ATM networks to provide an adaptive service class that maximizes bandwidth usage, which is ideal for IP traffic. ABR is an attractive solution for use in an autonomous system in the differentiated services model, especially when edge routing is used in conjunction with an ATM core. By using an improved communications infrastructure it is possible to enhance the performance and robustness of the current ABR flow control mechanism. The enhanced mechanism proposed in this paper reduces the response time when a switch senses congestion, resulting in a lower cell loss and reduced buffer space requirements in the switches. The enhanced explicit rate mechanism makes use of out-of-band signaling which improves the robustness of the flow control mechanism in times of severe congestion.