A method and apparatus for a communications network that executes a medium access control (MAC) protocol that permits multiple access to a shared medium or shared switching fabric. The MAC protocol uses a bandwidth allocator to regulate access to the network by sending a permission message to a node, allowing it to transmit to a specific set of nodes for a specific length of time. The medium and switching fabric can carry one or more protocols, each of varying framing format and native bitrate. The switching fabric provides a connection-oriented bufferless data transport service that preserves frame ordering. An illustrative embodiment uses a slotted master/slave time-division multiplexed access (TDMA) scheme to allow flexible provisioning of network bandwidth.