Supervisor Engine 2 acts as the control module for the new architecture built around the crossbar fabric that interconnects all the line cards with point-to-point, full-duplex serial connections. Supervisor Engine 2 is a key component of the CEF-based distributed forwarding architecture.PFC2 is a critical component of the distributed forwarding architecture. With Supervisor Engine 2, both Layer 2 and Layer 3 performance is doubled to 30 Mpps. A Supervisor Engine 2 equipped with a PFC2 and an optional MSFC2 enables a distributed forwarding mechanism for both Layer 2 and Layer 3 that is an effective solution for service providers as well as large enterprises. In a CEF-based architecture, a FIB and an adjacency table is created for Layer 3 forwarding. This FIB has the most current routing information and eliminates the need for the first packet of every flow to be switched in software. When an MSFC2 is not present, Layer 2 forwarding is also performed centrally in hardware, via ASICs, at 30 Mpps. MSFC2 is, however, required for both Layer 3 central forwarding at 30 Mpps as well as distributed forwarding. This is because distributed forwarding is only supported in supervisor Cisco IOS software, which requires an MSFC2. IP multicast replication and forwarding is also performed directly in hardware. Thus, a Supervisor Engine 2 can be deployed in scenarios with or without an MSFC2 for higher centralized forwarding performance. The FIB and adjacency tables are capable of storing 128K entries each.