Abstract: A system and method are provided for controlling packet header information in a packet communications switch fabric. The method comprises: programming the cell header overhead (OH) field definitions; accepting a packet including a plurality of cells and corresponding cell headers, each cell header including a plurality of overhead fields; defining the cell header OH fields; and, transmitting the packet. Defining the cell header OH fields includes defining cell header OH field location, position, meaning, structure, and length. In other aspects, the method comprises redefining the cell header overhead fields, once they are accepted. For example, the OH field information can be modified, relocated, or an OH field can be added to the cell header. In yet other aspects, the OH field information can be extracted and/or reformatted.

Abstract: A system and method are provided for communicating control information in a switch fabric. The method comprises: on a switch card, establishing a plurality of crossbars controlled by an arbiter; initiating a control message; and, distributing the control message on a switch card token bus connecting the crossbars and arbiter elements. Distributing the control message on a switch card token bus connecting the crossbar and arbiter elements includes daisy-chain connecting the elements with a cyclical bus. In some aspects of the method, establishing a plurality of crossbars controlled by an arbiter includes identifying each element with a unique address. Then, initiating a control message includes initiating a control message with an attached address. Distributing the control message on a switch card token bus includes the substeps of: daisy-chain passing the control message between elements; and, terminating the message at an element having an address matching the address attached to the control message.

Abstract: A system and method are provided for communicating TDM communications through a packet switch fabric. The method comprises: accepting native TDM frames; converting the native TDM frames to fabric-cellified TDM frames; differentiating the cells of each frame into time slots; interleaving the frame time slots; TDM scheduling the interleaved frame time slots; and, routing the interleaved frame time slots between input port cards and output port cards on backplane data links through an intervening crossbar. TDM scheduling the interleaved frame time slots includes: an input port card ingress memory subsystem (iMS) receiving a first TDM configuration schedule including interleaved frame time slots cross-referenced to backplane transmission times; and, an output port card egress MS (eMS) receiving a second TDM configuration schedule including interleaved frame time slots cross-referenced to egress channel transmission times. Then, the routing is performed in response to the TDM schedules.

Abstract: A system and method are provided for tolerating control link faults in a packet communications switch fabric. The method comprises: accepting information packets including a plurality of cells, at a plurality of port card ports, the plurality of information packets addressing a plurality of port card ports; selectively connecting port card ports to port card backplane data links; in response to backplane control link communications, selectively connecting port card backplane data links and crossbars; sensing a connection fault in a control link; and, in response to sensing the control link fault, reselecting connections between the port card ports and the port card backplane data links. In some aspects, selectively connecting port card backplane data links and crossbars includes: for a particular backplane data link, fixedly connecting each port card to a corresponding interface of an assigned crossbar; and, selectively enabling the connection to each crossbar.