Method and apparatus for dynamically allocating bandwidth on a TDM bus

The present invention relates to methods and apparatus providing for a switching hub in which an asynchronous transfer mode (ATM) switch is utilized as a backplane bus. Bus arbitration, i.e., allocation of bandwidth, on the bus for autonomous ATM and LAN switching modules coupled thereto is dynamically controlled according to the needs of the various modules. In particular, the present invention allows time division multiplexing of the bus under programmatic control such that each module, e.g., an Ethernet or Token Ring module, is allowed a desired number of cell slots on the bus during which to transfer data, which the module has translated into ATM cells, across the bus.