The Quad OC-12/STM-4 packet-over-SONET/SDH line card is a high-density interface card that offers industry leading switching performance and class-of-service (CoS) features for delivering advanced end-to-end networking features. The high performance switching engine integrates WRED and the Cisco innovative ASIC-based queue scheduling algorithm Modified Deficit Round Robin (MDRR) in the core of the network. These allow service providers to offer differentiated services with deterministic traffic behavior in the core of the network. This unique combination of features provides a versatile solution allowing a service provider to deploy a single interface in either a core application or a high-capacity aggregation application. This level of flexibility helps improve protection of investment, which is ideal given the dynamic nature of an Internet-driven economy.