A flexible broadband packet switch for a multimedia integrated network

The authors propose a `flexible´ switch architecture that can be the basis of high-performance packet switches for B-ISDN (broadband integrated service digital network) nodes. LANs (local area networks), and PBXs (private branch exchanges). This switch is being implemented for the Multimedia Integrated Network for Telecommunications (MINT) project, which will support voice, video, and data traffic. The switch fabric supports multiple priorities, has a programmable service policy, and has several field-selectable options to match system requirements. In addition, the number of cell buffers and the number of input/output ports all can be easily increased when needed. However, the architecture is most appropriate for small (e.g. up to 32×32) broadband packet asynchronous transfer mode switches, because the internal switch fabric is fully connected. The switch uses output queuing to achieve the best possible delay-throughput performance. Cells are stored in RAMs rather than FIFOs (first in, first-outs), thereby exploiting the memory density of RAM chips and permitting cells of different priorities to use the same chip. The switch allows RAM-based buffer sharing, and judiciously wastes some of the memory to simplify the switch´s control circuitry