Bay Networks, Inc.

Nortel Networks Corporation

Jeff Prince

Mike K Noll

Randy Ryals

H Earl Ferguson

Earl Ferguson

Michael Yip

Bobby J Johnson

Gururaj Singh

Bobby R Johnson, Jr

A device for switching data packets providing for local packet switching and non-local ATM switching. The device provides a packet switch coupled with LAN ports and provides for local switching between the LAN ports over the packet switch. Packets not known to be destined for data terminal equipment coupled with one of the ports are segmented and switched over an ATM backplane, switch or network.

LAN/ATM switch having local packet switching and an ATM core fabric

The switch fabric of the ATM switch, i.e., the ATM switch backplane bus, switches a cell based on routing information provided by the source LAN or ATM module to an output port on a destination LAN or ATM module of the switching hub. In the described system, the ATM switch is preconfigured to provide a fully connected topology between ports of all modules. In one embodiment, ATM cells transmitted across the ATM switch fabric between a source LAN or ATM module and a destination LAN module, e.g., Token Ring, FDDI or Ethernet, is accomplished by way of a routing tag prepended on the ATM cells. The routing tag provides both unicast and multicast group destination information such that the ATM cells are routed to the appropriate port on a given destination module without the need to establish a virtual circuit between the source module and the destination module using VPI/VCIs.

Method and apparatus for transmitting cells across an ATM switch bus

In a segmentation and reassembly module in a local area network switch module, a method and apparatus for storing fixed length data cells received from an ATM network in a plurality of memory buffers during the reassembly of the data cells in to a variable length data packet to be transmitted on an attached local area network.

Memory architecture for a local area network module in an ATM switch

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.

Pipeline architecture for an ATM switch backplane 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.

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Sunnyvale, CA, United States of America

Jeff Prince