The Switch Fabric Module is the core of the 3Com Switch 7700 system. The Switch Fabric performs route calculation and provides all Layer 3 switching functionality. It also performs Layer 2 switching between interface modules and where on-board Layer 2 switching is not possible. Based on the address-forwarding table, the hardware performs line-speed switching of Layer 2 / Layer 3 data packets. VLANs, link aggregation, QoS traffic classification and prioritization, and ACLs (Access Control Lists) are also supported by the hardware.