The Cisco I-Flex design combines shared port adapters (SPA) and SPA interface processors (SIP), leveraging an extensible design that enables service prioritization for voice, video and data services. Enterprise and service provider customers can take advantage of improved slot economics resulting from modular port adapters that are interchangeable across Cisco routing platforms. The I-Flex design maximizes connectivity options and offers superior service intelligence through programmable interface processors that deliver line-rate performance. I-Flex enhances speed-to-service revenue and provides a rich set of QoS features for premium service delivery while effectively reducing the overall cost of ownership.The Cisco 7304 10/100 Fast Ethernet SPA is designed to meet the growing demand for customers who need cost-effective and simple connectivity for Internet gateway, peering, or Metro Ethernet access applications. This SPA is a single-width pluggable module capable of supporting four 10/100 Fast Ethernet copper (RJ-45) connections. Two SPAs fit into one carrier card in a single line-card slot of the Cisco 7304 Router, greatly extending port density and modularity.