Integration of Rate and Credit Schemes for ATM Flow Control

† IEEE Network Mag., Mar. 1995, pp. 49–56. ATM is the first switching technology that can support both fixed bandwidth services similar to circuit switching, and highly variable bandwidth services similar to packet switching, in a single integrated environment [1]. Definitions for traffic management for services with a fixed traffic profile were completed by the ATM Forum in their version 3.0 specification [2]. For the last year and a half the Traffic Management Group of the ATM Forum has been working on flow control for the highly variable bandwidth services typically supported by packet switching networks. In such services there is no explicit contract between the network and the user specifying the traffic profile and quality of service expected. Rather, the network is expected to provide each user with a fair share of the amount of bandwidth dynamically available. It is expected that if the user adjusts the transmission rate according to the feedback from the network then cell loss will remain low. The ATM Forum has termed such services available bit rate (ABR) services.