An adaptive rate-based congestion control scheme for ATM networks

Abstract

The ATM Forum has chosen a rate-based scheme as an approach to congestion control for Available Bit Rate (ABR) services. So far many rate-based schemes, such as Forward Explicit Congestion Notification (FECN), Backward Explicit Congestion Notification (BECN), and Proportional Rate Control Algorithm (PRCA), has been proposed. In FECN and BECN, which use negative feedback rate control, the overall network congestion collapse may occur, if all notification cells in backward direction experience extreme congestion. The PRCA use positive feedback to solve the drawbacks of the FECN and BECN, but unfair distribution of available bandwidth among Virtual Connections (VCs) may occur. To resolve the problems of the existing rate-based schemes, in this paper, we propose a new adaptive congestion control scheme called the self detective congestion control (SDCC) scheme. We show that the SDCC scheme can achieve good fairness performance among connection classes existing in the network. In transient behavior, the SDCC scheme offers fast access to available bandwidth, which is a sensible requirement, particularly in LAN and MAN environments. Furthermore, by allocating control cells based on networks scales, the scheme is able to control a number of greedy sources with moderate size buffers.