Connection admission control of ATM network using integrated MLP and fuzzy controllers Nelson O.L. Ng * , C.K. Tham Department of Electrical Engineering, National University of Singapore, Singapore 119260, Singapore Abstract This paper presents a new approach to the problem of call admission control (CAC) of variable bit rate (VBR) trac in an asynchronous transfer mode (ATM) network. Our approach employs an integrated neural network and fuzzy controller to implement the CAC controller. This scheme capitalizes on the learning ability of a neural network and the robustness of a fuzzy controller. Experiments show that this scheme is able to achieve high throughput and low cell loss while achieving fairness among dierent classes of VBR trac. For comparison, we have also implemented four other CAC schemes: (1) peak bandwidth method, (2) equivalent bandwidth method, (3) average bandwidth method and (4) neural network quality of service (QoS) predictor. Results of these experiments are presented in this paper. Ó 2000 Elsevier Science B.V. All rights reserved. Keywords: ATM; Call admission control; Neural network; Fuzzy control 1. Introduction Asynchronous transfer mode (ATM) is a high-speed packet switching technology for the broadband integrated services digital network (B-ISDN), in which various kinds of communica- tion services, such as voice, video and data are transferred over high-speed links [1]. This tech- nology has gained acceptance as the backbone high-speed network of the future, as well as the lower bandwidth link to homes and desktops for interactive multimedia services. ATM supports dierent service classes, such as constant bit rate (CBR), variable bit rate (VBR), unspeci®ed bit rate (UBR) and available bit rate (ABR). Due to the diverse mix of trac types and ser- vice requirements, resource allocation in B-ISDN must be related both to the trac parameters and the quality of service (QoS) negotiated between the user and the network at the establishment of each call. Most of the published connection admission (CAC) criteria allocate resources based on the availability of bandwidth necessary to guarantee the negotiated QoS. These approaches use either the peak or average cell rate as CAC criteria. More elaborate methods introduced the concept of equivalent capacity, which gives a value between the peak and average, depending on the type of trac and desirable maximum cell loss rate. Equivalent bandwidth computation focuses on the bandwidth requirement of the bit rate generated by sources, and not on the dierent interactions that take place within the network. In addition, Computer Networks 31 (2000) 61±79 www.elsevier.com/locate/comnet * Corresponding author. Tel.: +65-373-2826; fax: +65-273- 5452. E-mail addresses: nonnlum@starnet.gov.sg (N.O.L. Ng), eletck@nus.edu.sg (C.K. Tham). 1389-1286/00/$ - see front matter Ó 2000 Elsevier Science B.V. All rights reserved. PII: S 1 3 8 9 - 1 2 8 6 ( 9 9 ) 0 0 1 2 4 - 3