The Route Switch Processor (RSP2) is the main system processor module for the Cisco 7505 router. It combines all of the switched routing and high-speed switching functions of the separate Route Processor (RP) and Switch Processor (SP), which are used in the Cisco 7000 series routers. The RSP2 supports high system availability (HSA), which is a feature in Cisco IOS Release 11.1(4) or a later release of 11.1, that allows two RSPs to be used in a Cisco 7507 or Cisco 7513 router. By default, the system master is the RSP that occupies the first RSP slot in the router: slot 2 in the Cisco 7507, and slot 6 in the Cisco 7513. The Cisco 7505 and Cisco 7576 routers do not support the HSA feature.