CISCO 2800 IP VOICE FEAT PACK Cisco IOS (Internetworking Operating System) software is the platform that delivers network services and enables networked applications. Cisco routers and access servers run the industry-leading Cisco IOS software. Cisco IOS software seamlessly links heterogeneous media and devices across the broadest set of protocols. The management services inherent in Cisco IOS software provide necessary tools that allow you to grow your network to keep up with rapidly changing business requirements.