VSrVD feature in the ABR service of ATM networks

Ž . The Available Bit Rate ABR service in ATM networks uses end-to-end rate-based flow control to allow fair and w efficient support of data applications over ATM networks. One of the architectural features in the ABR specification ATM x Forum, ATM Traffic Management Specification Version 4.0, April 1996 is the Virtual SourcerVirtual Destination Ž . VSrVD option. This option allows a switch to divide an end-to-end ABR connection into separately controlled ABR Ž . Ž . segments by acting like a virtual destination on one segment, and like a virtual source on the other. The translation and Ž . propagation of feedback in the VSrVD switch between the two ABR control segments called ‘‘coupling’’ is implementation specific. In this paper, we model a VSrVD ATM switch and study the issues in designing the coupling between ABR segments. We identify a number of implementation options for the coupling and show that the choice of the implementation Ž . Ž . option significantly affects the system performance in terms of a the system stability in the steady state, b the time to Ž . respond to transient changes and converge to the steady state, and c the buffer requirements at the switches. q 1998 Published by Elsevier Science B.V. All rights reserved. Ž . Ž .