Pipeline architecture for an atm switch backplane bus

Abstract

Methods and apparatus providing for a switching hub in which an asynchronous transfer mode (ATM) switch is utilized as a backplane bus to which a plurality of LAN and ATM modules are coupled. Each LAN or ATM module is an autonomous switching module. Thus, for example, an Ethernet LAN module may receive Ethernet packets on one of its ports and transmit the packets out another one of its ports according to well known standards and techniques for bridging such packets, without the need for such packets to be translated into ATM cells and transmitted across the ATM switch backplane bus. In the event a source LAN or ATM module in the switching hub has data to transmit to a destination LAN or ATM module, the destination module is notified prior to transmission of ATM cells across the backplane to the destination module, thus allowing the destination module to schedule reception of the ATM cells off the backplane between its autonomous switching activities, thereby enhancing the utilization of the switching capacity of the autonomous module. Likewise, a source LAN or ATM module is notified two cell slots prior to obtaining ownership of the backplane that, indeed, it will obtain ownership of the backplane bus, so that it may also more fully utilize its switching capacities by performing switching activities during the next two cell slots until such time as it is provided ownership of the backplane data bus and begins transmitting ATM cells to a destination module.