System and method for a quality of service in a multi-layer network element

摘要

A multi-layer network element for forwarding received packets from an input port to one or more output ports with quality of service. When output queues exceed or meet a threshold value below the queue's capacity packets are ramdomly discarded. When the queue becomes full, the network element determines which flow caused the queue to overflow. The priority of that flow is lowered. In a multicast packet, the packet may have different priorities at each output port. Scheduling of multiple output queues at each output port uses a weight round robin approach that allocates a weight portion of packets to transmit at each time interval. A packet is not interrupted during its transmission, even if the weight portion is met during a packet's transmission. The excess number of bytes transmited as a result of not interrupting the packet are accounted for in the next round.