Ethernet Oversubscription Aggregator that allows system vendors to offer high-density Gigabit Ethernet line cards without compromising quality of service. It provides a best-in-class L4 through L2 classification engine that can identify critical applications and segregate them into one of four priority queues per port. With a 128MB external oversubscription buffer, Barcelona is equipped to minimize packet loss, guarantee key traffic delivery, and ensure a graceful WRED drop policy. Industry-standard policing and marking functions support SLA enforcement in both enterprise and transport applications, and a flexible shaper can allocate bandwidth per priority and per port for transmission to the upstream processor. With this breakthrough set of features, Barcelona enables a new standard in oversubscription service quality.