A QoS provisioned CIOQ ATM switch with m internal links is proposed in this paper. In the proposed switch the incoming cells at each input port are discriminated into service classes. For each service class, at each input port, a single buffer is provided whereas each output port needs m buffers, where in is the number of internal links (or channels) that connect each input port to each output port. The proposed switch uses physical internal links instead of time division, thus no speedup is required. The results of simulation of proposed switch using simple priority schedulers show that for m ≥ 3 the number of cell waiting at input queue is small, less than 0,1 cells in average, independent of service classes. The proposed switch has also the feature that facilitates the choice of scheduler in order to satisfy the QoS of each class of service. © Springer-Verlag 2004.3124 698703Motoyama, S., Petr, D.W., Frost, V.S., Input - Queued switch based on a scheduling algorithm (1995) Electronics Letters, 31 (14), pp. 1127-1128. , JulyMcKcown, N., Varaiya, P., Walrand, J., Scheduling cells in an Input-Queued Switch (1993) Electronics Letter, 3 (11), pp. 323-325. , DecemberMotoyama, S., Ono, L.M., Mavigno, M.C., An iterative cell scheduling algorithm for ATM input-queued switch with service class priority (1999) IEEE Communications Letters, 3 (11), pp. 323-325Anderson, T.E., Owicki, S.S., Saxe, J.B., Tacker, C.P., High Speed Switch Scheduling for Local Area Networks (1992) Proc. Fifth International Conference on Architectural Support for Programming Languages and Operating Systems, pp. 98-110. , OctGenda, K., Yamanaka, N., Doi, Y., A High-Speed ATM Switch that uses a Simple Retray Algorithm and Small Input Buffers (1993) IEICE Trans. Commun., E76-B (7). , JulyMinkenberg, C., Engbersen, T., A combined Input and Output Queued Packet-Switched System Based on PRIZMA Switch-on-a-Chip Technology (2000) IEEE Commun. Magazine, 38 (12), pp. 70-77. , DecemberMotoyama, S., Santos, C.R., A Combined Input-Output Queuing ATM Switch with m Internal Links for Cell Transfer (2002) International Telecommunications Symposium, pp. 142-146. , SeptemberMotoyama, S., Santos, C.R., Performance Analysis of a CIOQ ATM Switch with m Internal Links for Cell Transfer (2002) 10th International Conference on Software, Telecommunications &ampComputer Networks - SoftCom 2002, pp. 636-640. , November