The nature of telecommunications networks is rapidly changing. Commodity smart mobile phone frameworks such as Android and Openmoko invite developers and end users to build applications, modify the behavior of the phone, and use network services in novel ways. However, while simultaneously spurring incredible innovation, the move to open systems alters the underlying performance and security assumptions upon which the network was designed. Such changes invite vulnerabilities ranging from merely vexing phone glitches to catastrophic network failures. The current infrastructure lacks the basic protections needed to protect an increasingly open network, and it is unclear what new stresses and threats open systems and services will introduce. This research analytically and experimentally investigates defensive infrastructure addressing vulnerabilities in open cellular operating systems and telecommunications networks. In this, we are exploring the requirements and design of such defenses in three coordinated efforts; a) extending and applying formal policy models for telecommunication systems, and provide tools for phone manufacturer, provider, developer, and end-user policy compliance verification, b) building a security-conscious distribution of the open-source Android operating system, and c) explore the needs and designs of overload controls in telecommunications networks needed to absorb changes in mobile phone behavior, traffic models, and the diversity of communication end- points. This research symbiotically supports educational goals at the constituent institutions by supporting graduate and undergraduate student research, and is integral to the security and network curricula.