The Cisco 6400 series universal access concentrator (UAC) is a carrier-class service gateway allowing service providers to deploy value-added services as part of a next generation Internet access architecture. Thus, providers may converge on a single narrowband and broadband access architecture for digital subscriber line (DSL).The Cisco 6400 enables this capability by combining both Asynchronous Transfer Mode (ATM) switching and routing in a single scalable platform, drawing on the rich feature set of Cisco IOS software and the widely deployed Catalyst 8500 (former LightStream (LS)1010) and Cisco 7200 hardware. The Cisco 6400 is also one of the first Cisco products to combine full Network Equipment Building Systems (NEBS) certification with redundancy.