Abstract: A technique for forwarding multi-cast data packets in a communication network. Multi-cast packets are broadcast to every output port of the switch. The packet is thus buffered in each port. Then, all of the output ports, save those that are appropriate output ports for the packet, drop the packet. Accordingly, the output ports that did not drop the packet forward the packet to the network. A control packet that follows the packet may then instruct the ports regarding which ports are to drop the packet and which ports are to forward the packet. This technique has an advantage of efficiently handling multi-cast packets.

Abstract: A technique for forwarding multi-cast data packets in a communication network. Multi-cast packets are broadcast to every output port of the switch. The packet is thus buffered in each port. Then, all of the output ports, save those that are appropriate output ports for the packet, drop the packet. Accordingly, the output ports that did not drop the packet forward the packet to the network. A control packet that follows the packet may then instruct the ports regarding which ports are to drop the packet and which ports are to forward the packet. This technique has an advantage of efficiently handling multi-cast packets.

Abstract: A non-blocking virtual switch architecture for a data communication network. The switch includes a plurality of input ports and output ports. Each input port may be connected to each output port by a directly connected network or by a mesh network. Thus, data packets may traverse the switch simultaneously with other packets. At each output port, buffer space is dedicated for queuing packets received from each of the input ports. An arbitration scheme is utilized to forward data from the buffers to the network. Accordingly, the use of a crossbar array, and associated traffic bottlenecks, are avoided. Rather, the system advantageously provides separate buffer space at each output port for every input port.

Abstract: A metro switch and method for transporting data configured according to multiple different formats. In one aspect, a network system and method that provides for point-to-point communication of data of various different formats such as ATM, frame relay, PPP, Ethernet, etc. Accordingly, the invention may interface disparate network devices, such as private networks and other entities that operate according to various different protocols and that use various different media. At ingress points to the system, the data is received from data sources and configured according to a universal format. This allows data from origins that use different data formats and/or transmission media to be mixed and transported onto the same media. The data is then transported to one or more destinations using this format. At egress points of the system, the data is reconverted to its original format for use at its destination.

Abstract: A quality of service technique for a data communication network. Using a combination of Time Division Multiplexing (TDM) and packet switching, the system is configured to guarantee a predefined bandwidth for a client, which, in turn, helps manage delay and jitter in the data transmission. An ingress processor operates as a bandwidth filter, transmitting packet bursts to distribution channels for queuing in a queuing engine. The queuing engine holds the data packets for subsequent scheduled transmission over the network, which is governed by predetermined priorities. These priorities may be established by several factors including pre-allocated bandwidth, system conditions and other factors. A scheduler then transmits the data received by the queuing engine by a self-clocked fair queuing method.

Abstract: A technique for time division multiplex (TDM) forwarding of data streams. The system uses a common switch fabric resource for TDM and packet switching. In operation, large packets or data streams are divided into smaller portions upon entering a switch. Each portion is assigned a high priority for transmission and a tracking header for tracking it through the switch. Prior to exiting the switch, the portions are reassembled into the data stream. Thus, the smaller portions are passed using a “store-and-forward” technique. Because the portions are each assigned a high priority, the data stream is effectively “cut-through” the switch. That is, the switch may still be receiving later portions of the stream while the switch is forwarding earlier portions of the stream. This technique of providing “cut-through” using a store-and-forward switch mechanism reduces transmission delay and buffer over-runs that otherwise would occur in transmitting large packets or data streams.

Abstract: A network routing switch includes a crosspoint switch, a set of Ethernet I/O ports, a set of ATM I/O ports, a reassembly unit for converting ATM transmissions into Ethernet transmissions, and a segmentation unit for converting Ethernet transmissions into ATM transmissions. As an ATM I/O port receives cells of an ATM transmission from an external source it stores them until the transmission is complete and then sends the ATM transmission through the crosspoint switch either to a forwarding ATM port or to the reassembly unit depending on whether the ATM transmission is to be forwarded as an ATM or Ethernet transmission. When the reassembly unit receives an ATM transmission it converts it to an Ethernet transmission and forwards it through the crosspoint switch to a forwarding Ethernet I/O port.