Mitsubishi Electric Research Laboratories Cambridge Research Center Technical Report 94-17 September 30, 1994 A General Purpose Queue Architecture for an ATM Switch Hugh C. Lauer Abhijit Ghosh Chia Shen Abstract This paper describes a general purpose queue architecture for an ATM switch capable of support- ing both real-time and non-real-time communication. The central part of the architecture is a kind of searchable, self-timed FIFO circuit into which are merged the queues of all virtual channels in the switch. Arriving cells are tagged with numerical values indicating the priorities, deadlines, or other characterizations of the order of transmission, then they are inserted into the queue. Entries are selected from the queue both by destination and by tag, with the earliest entry being selected from among a set of equals. By this means, the switch can schedule virtual channels indepen- dently, but without maintaining separate queues for each one. This architecture supports a broad class of scheduling algorithms at ATM speeds, so that guaranteed qualities of service can be provided to real-time applications. It is programmable because the tag calculations are done in microprocessors at the interface to each physical link connected to the switch. Presented at Massachusetts Telecommunications Conference, University of Massachusetts at Lowell, Lowell, MA, October 25,1994. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories of Cambridge, Massachusetts; an acknowledgment of the authors and individual contributions to the work; and all applicable por- tions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories. All rights reserved. Copyright © Mitsubishi Electric Research Laboratories, Inc., 1994 201 Broadway, Cambridge, Massachusetts 02139