towards supporting network-centric warfare. These include the Cooperative Engagement Capability (CEC) of the United States Navy and the BCT Network of the United States Army. Net-Centric Enterprise Solutions for Interoperability (NESI) provides, for all phases of the acquisition of net-centric solutions, actionable guidance that meets network-centric warfare goals of the United States Department of Defense. The guidance in NESI is derived from the higher level, more abstract concepts provided in various directives, policies and mandates such as the Net-Centric Operations and Warfare Reference Model (NCOW RM) and the ASD(NII) Net-Centric Checklist. Doctrinal tenets in United States The doctrine of network-centric warfare for the United States armed forces draws its highest level of guidance from the concept of "team warfare", meaning the integration and synchronization of all appropriate capabilities across the various services, ranging from Army to Air Force to Coast Guard. This is part of the principle of joint warfare. The tenets of network-centric warfare are: Tenet 1: A robustly networked force improves information sharing. Tenet 2: Information sharing and collaboration enhance the quality of information and shared situational awareness. Tenet 3: Shared situational awareness enables self-synchronization. Tenet 4: These, in turn, dramatically increase mission effectiveness. Net-Centric operations are compatible with Mission Command doctrine, which theoretically allows considerable freedom of action for combat troops,United States Marine Corps (1996). Command and Control. Washington, D.C.: Department of the Navy, Headquarters, United States Marine Corps, Doctrine Publication MCDP 6. and with more decentralized approaches to Command and Control (C2). Some architectural and design challenges The complexity of the Joint Tactical Radio System (JTRS) offers insight into the challenges of integrating numerous different communications systems into a unified whole. It is intended to be a software-defined radio for battlefield communications that will be backwards compatible with a very large number of other military and civilian radio systems. An April 10, 2008 GAO report (GAO FCS report) highlighted the scalability of the network as a major risk factor to the Network Centric FCS program. The proposed system will be unable to network all the units into one self-forming, self-healing network. The problem of coordinating bandwidth usage in a battlespace is a significant challenge, when every piece of mobile equipment and human participant becomes a potential source or relay of RF emissions. It is difficult to efficiently transfer information between networks having different levels of security classification. Although multi-level security systems provide part of the solution,