The Cisco 6400 carrier-class broadband aggregator is a high-performance, scalable service gateway that enables the selection and delivery of broadband network services, virtual private networks (VPNs), and voice- and entertainment-driven traffic over the full suite of access media. The Cisco 6400 combines the richness of Cisco IOS software, Asynchronous Transfer Mode (ATM) switching and routing capabilities, and value-added service selection in a modular, scalable, redundant, Network Equipment Building Standard (NEBS) certified and ETSI form factor.The Cisco 6400 consists of a fault-tolerant mid-range ATM switching core and multiple fault tolerant routing engines. The ATM switch, based on Catalyst 8500 + Per-Flow Queuing (PFQ) technology, provides the necessary ATM switching and traffic management capabilities, while the router modules enable the service provider to offer scalable Layer 3 services. ATM interfaces connect the Cisco 6400 to dial access servers, DSLAMs, and Cisco IP DSL Switches, and ATM and packet interfaces connect to the network core. The Cisco 6400 is designed for use in high-availability environments such as operating companies` central offices (directly or via co-location), ISP offices, and corporate premises. As such, it includes switch, router, and line card redundancy, as well as 12-inch packaging (key for central office deployment).The Cisco 6400 may reside within the operating company's infrastructure (directly or via co-location) to aggregate access media (DSL, cable, wireless, and dial), serving as the intelligent equal access point that allows a multitude of operating companies and service providers access to the end users. In addition, the Cisco 6400 may reside at the network edge between the operating companies and ISP or corporation, providing the aggregation of sessions and tunnels as well as service and network selection capabilities required in the delivery of advanced broadband services.