Performance issues in public ABR service

The available bit rate (ABR) service attracted much attention during the negotiations leading to Traffic Management Specification Version 4.0, finalized by the ATM Forum. In thr ABR service, feedback flow control of the source rate is provided in response to the changing asynchronous transfer mode (ATM)-layer transfer characteristics. The reference behavior of the source end system, the destination end system, and the switch, as detailed in the specification, allows cooperative control among these systems. The performance of the public ABR service is discussed in connection with the evolution of ATM switches. Public networks with first-generation switches provide an ABR service with a limited peak cell rate (PCR), while those with second-generation switches can provide an ABR service with any PCR. In such networks, TCP-over-ABR works well. Point-to-multipoint ABR will be provided in advanced switches. A method is proposed for maintaining the throughput of point-to-multipoint ABR when the number of leaves is increased