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