Pipelined packet switching and queuing architecture

A pipelined linecard architecture for receiving, modifying, switching, buffering, queuing and dequeuing packets for transmission in a communications network is disclosed. The linecard has two paths: a receive path and a transmit path. In the receive path, received packets are processed and switched in an asynchronous, multi-stage pipeline. The pipelined switch operates on several packets in parallel while determining each packet's routing destination. Once that determination is made, each packet is modified to contain new routing information. Each packet is buffered and enqueued for transmission over the switching fabric to a destination linecard. The transmit path includes a buffer/queuing circuit similar to that used in the receive path. Both enqueuing and dequeuing of packets is accomplished using a CoS-based decision making apparatus.