The Cisco ® I-Flex design combines shared port adapters (SPAs) and SPA interface processors (SIPs), using an extensible design that enables service prioritization for voice, video, and data services. Enterprise and service provider customers can use improved slot economics resulting from modular port adapters are interchangeable across Cisco routing platforms. The I-Flex design maximizes connectivity options and offers superior service intelligence through programmable interface processors, which deliver line-rate performance. I-Flex enhances speed-to-service revenue and provides a rich set of quality-of-service (QoS) features for premium service delivery while effectively reducing the overall cost of ownership. This data sheet contains the specifications for the Cisco 4/8-Port OC-3c/STM-1 Packet over SONET SPAs The Cisco 4- and 8-Port OC-3 POS SPAs are available on high-end Cisco Systems® routing platforms offering the benefits of network scalability with lower initial costs and ease of upgrades. The Cisco SPA/SIP portfolio continues the Cisco focus on investment protection along with consistent feature support, broad interface availability, and the latest technology. The Cisco SPA/SIP portfolio allows deployment of different interfaces (Packet over SONET/SDH [POS], ATM, Ethernet, and so on) on the same interface processor. The Cisco 4- and 8-Port OC-3 POS SPAs are available with four or eight Small Form-Factor Pluggable (SFP) interfaces. SFP modules are available in multiple optical reaches from 2 to 80 km.