Abstract: A method and system for transmitting a loopback cell within an ATM connection. The method comprises the steps of detecting in an input adapter whether or not an incoming ATM cell includes a loopback condition indicator. If so, specific routing labels are appended to the incoming ATM cell indicating that the incoming cell is a loopback cell to be looped back on the connection such that the switch engine of the switching node transfers the loopback cell to the same port of the input adapter utilizing the appended routing labels.

Abstract: A method and system for enforcing a transmission control parameter for a virtual connection comprising multiple cells within an input port. The virtual connection has a nominal inter-cell arrival rate increment. Each of the cells are associated with a theoretical arrival time and an early arrival limit, wherein a difference of the early arrival limit from said theoretical arrival time delineates a lower boundary of a good zone, while the theoretical arrival time minus the sum of the early arrival limit and the nominal inter-cell arrival rate increment delineates an upper boundary of the good zone. The method includes determining an actual arrival time for an incoming cell from the cells that make up the virtual connection. Next, the actual arrival time is compared to the upper boundary and the lower boundary to determine whether or not the actual arrival time falls within the good zone.

Abstract: A system and method for selecting one port among multiple output ports having various transmission rates attached to an output adapter of a switching node in a data transmission network and enabling it to transmit its data over the network. The system of the present invention includes a storage device that contains a list of identification codes for the ports. The identification code list is arranged in a prioritized order from the port having the highest transmission rate to the port having the lowest transmission rate. The system further includes port service request means that generate a service request signal for each port, wherein the service request signal has a frequency corresponding to the transmission rate of the object port.

Abstract: A method and system for transmitting a loopback cell within an ATM connection. The method comprises the steps of detecting in an input adapter whether or not an incoming ATM cell includes a loopback condition indicator. If so, specific routing labels are appended to the incoming ATM cell indicating that the incoming cell is a loopback cell to be looped back on the connection such that the switch engine of the switching node transfers the loopback cell to the same port of the input adapter utilizing the appended routing labels.