Abstract: A queuing system (230) stores a package (246) derived from an ATM cell, the package including an internal interface header (IIH) and either an ATM cell payload or an AAL2 packet. The queuing system comprises a queue (312, 320) for storing the package, as well as a processor which executes plural functions. A time stamping function applies a time stamp upon storage of the package in the queue. The time stamping function can apply the time stamp to a package as replacement of the internal interface header. A time stamp checking function uses the time stamp to make a determination whether the tenure of the package in the queue is longer than permissible. The time stamp checking function can make the tenure determination in conjunction with a potential readout of the package from the queue. Alternatively, time stamp checking function can make the tenure determination when invoked by a queue monitoring function which monitors a fill level of the queue (e.g., when a queue fill level exceeds a threshold).

Abstract: An ATM switching node has a queuing resource (230) connected to an ATM switch core (30). The queuing resource provides centralized queuing for ATM cells destined for routing through the ATM switch core to plural output links. The ATM switch core routes an ATM cell destined for any output link requiring queuing to the centralized queuing resource. ATM cells for output links not requiring queuing are not directed to the queuing resource. The queuing resource has a link multiplexer (280) for each output link which is handled by the queuing resource. Each link multiplexer has both a first stage (304) and a second stage (302). The second stage comprises plural queues (312) for storing ATM packets and a second stage multiplexer (314) for selecting the ATM packets stored in the plural queues of the second stage for transmission to the first stage.