Abstract: An apparatus for and a method of collapsing multiple ports to a single queue. The invention has applications in switching devices whereby several external ports share the same resource, such as a switching fabric. In order to allocate the resources fairly to all the ports, a scanning method is used to allocate the division of the resources to each of the external ports. A port combiner circuit continuously scans or polls the external ports in a round robin fashion checking for a port ready to input data. An external port in a ready state transfers its frame data to an input queue. The frame data is written to the next available segment in the input queue which is comprised of RAM configured as a circular buffer. After a frame is written, the write pointer is incremented to point to point to the next available segment. The next frame segment read out of the input queue is always the first one written. The queue thus formed received multiple inputs but has a single output.

Abstract: A network having at least one emulated local area network (LAN) therein includes groups of legacy LAN workstations, network switches and an ATM switch. The network switches are each connectable to one of the groups of the legacy LAN workstations. The ATM switch is connectable to the network switches and each network switch includes a cell memory, a cell memory manager, local switching apparatus and remote switching apparatus. The cell memory stores cells of data. The cell memory manager converts data back and forth between a format and a cell format, stores the cell format data in the cell memory and retrieves calls therefrom. The local switching apparatus locally switches cells of data among the group of legacy LAN workstations connectable to the network switch. The remote switching apparatus switches the cells of data from the network switch to a remote network switch via the ATM switch.

Abstract: A traffic management unit for implementing Traffic Management (TM) of Available Bit Rate (ABR) traffic on an Asynchronous Transfer Mode (ATM) network is described. The traffic management unit comprises a traffic management processor coupled to a traffic management memory. The traffic management processor is coupled between a data processor and an ATM interface. An Ethernet workstation is coupled to the data processor through an Ethernet interface. An ATM switch is coupled to the traffic management processor through the ATM interface. The traffic management unit is implemented as a unit separate from the cell scheduling data processor. In addition, in order to utilize network congestion information more efficiently, VCs are grouped according to their output destinations or their path through the network. Congestion feedback for one VC is applied to other VCs within the group.