independently developed systems Significantly the Department of Defense has edicted that commercial standards for electronics and telecommunications are to be utilized in preference to military standards in order to promote more rapid and lower cost acquisition of state-of-the-art technology. Two additional motivations for new standards are increased traffic requirements and increased system complexity. C3 applications and users have found significant benefit in increasing communication with programmati- ally unrelated data sources such as databases and sensors. There is an increase in internal communica- tions as well. Also systems have become more complex, forcing programs to develop modularized architectures. Software is replacing hardware as the most complicated component of communications and C2 systems to design, build, and maintain. Modularized architectures are required to simplif development and enable insertion of new technologies The primary computer-to-computer communications architecture has been the Open Systems Inter connection(OSI) Reference Model. The OSI Reference Model has been successful as a layered architecture with well-defined interfaces and specified division of functions. The Department of Defense has com- mitted to adopting an enhanced version of the osi protocols, called the government OSI Profile ( GOSIP). OSI/GOSIP integration into C3 systems is lagging because of delays in accredited vendor implementations and the cost of upgrading the existing communications infrastructure. NATO is also adopting standards for their joint procurement policies; to a significant degree they overlap commercial standards OSI brings to C3 a set of application services that had not been previously available. For example, the OSI electronic mail standards(usually called X 400) provide message forwarding, distribution list cre- ation and distribution, and obsolete message extraction among other services to users. In addition to the security protocols contained in the lower layers of the OSI stack, X 400 has its own security services uch as message origin authentication, message flow confidentiality, message content integrity, and nonrepudiation of delivery, services that are highly desirable in C3 environments. OSI also has enhanced file transfer and management capabilities, systems management, directory, and transaction processing, mong other application functions, all providing enhanced capability to C3 users g. Precision timing and position location(GPS). Navigation/position location historically is important and becomes more so in high dynamic maneuver warfare. With the introduction of the Global Positioning System(GPS), 3-dimensional positioning is available to the smallest of high-mobility nodes. Even with a less than complete satellite constellation, position accuracies can become less than 100 m h. Displays and workstations. High-resolution displays combined with programmable workstations and software lead to flexible node functions and consequently to flexible architectures. A C3 workstation could, in principle, support any of a number of C3I functions; a relocation of operators may be the only requirement to physically relocate a command node. Numerous decision aids are now being included within workstations and with their more comprehensive capability are now often described as decision support systems(DSS). Man-machine interface(MMI), as a result, grows in importance. i. Software techniques. With the growing computational power and memory capability of microprocessor systems,C3 system performance will increasingly be determined by software performance. The cost and complexity of software appears to expand in proportion to host computer capability and is more frequently becoming a system limiting factor. ADA is dictated to be the common programming language of the Defense Department; however, exceptions can be approved. Verification and validation(v&v) generated software and software maintainence have grown to necessitate organizational changes within the military Software standards have also increased in importance in new C3 systems. POSIX standards (published as IEEE 1003)govern the software interfaces to operating system services in various com puting platforms [NIST, 1990]. As such, they allow application programs written according to the standards to be reused. POSIX standardizes interfaces to security, networking, and diverse system services, including file management, memory and process management, and system administration services. POSIX.5 provides bindings for the ADA programming language Simulation and modeling. Both techniques are employed with the objective of designing or analyzing the performance of a C3I system. With the advent of faster computation, complex scenarios can be gamed" in near real time, and modeling will then be within the decision aid realm e 2000 by CRC Press LLC© 2000 by CRC Press LLC independently developed systems. Significantly the Department of Defense has edicted that commercial standards for electronics and telecommunications are to be utilized in preference to military standards in order to promote more rapid and lower cost acquisition of state-of-the-art technology. Two additional motivations for new standards are increased traffic requirements and increased system complexity. C3 applications and users have found significant benefit in increasing communication with programmati￾cally unrelated data sources such as databases and sensors. There is an increase in internal communica￾tions as well. Also systems have become more complex, forcing programs to develop modularized architectures. Software is replacing hardware as the most complicated component of communications and C2 systems to design, build, and maintain. Modularized architectures are required to simplify development and enable insertion of new technologies. The primary computer-to-computer communications architecture has been the Open Systems Inter￾connection (OSI) Reference Model. The OSI Reference Model has been successful as a layered architecture with well-defined interfaces and specified division of functions. The Department of Defense has com￾mitted to adopting an enhanced version of the OSI protocols, called the Government OSI Profile (GOSIP). OSI/GOSIP integration into C3 systems is lagging because of delays in accredited vendor implementations and the cost of upgrading the existing communications infrastructure. NATO is also adopting standards for their joint procurement policies; to a significant degree they overlap commercial standards. OSI brings to C3 a set of application services that had not been previously available. For example, the OSI electronic mail standards (usually called X.400) provide message forwarding, distribution list cre￾ation and distribution, and obsolete message extraction among other services to users. In addition to the security protocols contained in the lower layers of the OSI stack, X.400 has its own security services such as message origin authentication, message flow confidentiality, message content integrity, and nonrepudiation of delivery, services that are highly desirable in C3 environments. OSI also has enhanced file transfer and management capabilities, systems management, directory, and transaction processing, among other application functions, all providing enhanced capability to C3 users. g. Precision timing and position location (GPS). Navigation/position location historically is important and becomes more so in high dynamic maneuver warfare. With the introduction of the Global Positioning System (GPS), 3-dimensional positioning is available to the smallest of high-mobility nodes. Even with a less than complete satellite constellation, position accuracies can become less than 100 m. h. Displays and workstations. High-resolution displays combined with programmable workstations and software lead to flexible node functions and consequently to flexible architectures. A C3 workstation could, in principle, support any of a number of C3I functions; a relocation of operators may be the only requirement to physically relocate a command node. Numerous decision aids are now being included within workstations and with their more comprehensive capability are now often described as decision support systems (DSS). Man-machine interface (MMI), as a result, grows in importance. i. Software techniques. With the growing computational power and memory capability of microprocessor systems, C3 system performance will increasingly be determined by software performance. The cost and complexity of software appears to expand in proportion to host computer capability and is more frequently becoming a system limiting factor. ADA is dictated to be the common programming language of the Defense Department; however, exceptions can be approved. Verification and validation (V&V) of generated software and software maintainence have grown to necessitate organizational changes within the military. Software standards have also increased in importance in new C3 systems. POSIX standards (published as IEEE 1003) govern the software interfaces to operating system services in various com￾puting platforms [NIST, 1990]. As such, they allow application programs written according to the standards to be reused. POSIX standardizes interfaces to security, networking, and diverse system services, including file management, memory and process management, and system administration services. POSIX.5 provides bindings for the ADA programming language. j. Simulation and modeling. Both techniques are employed with the objective of designing or analyzing the performance of a C3I system. With the advent of faster computation, complex scenarios can be “gamed” in near real time, and modeling will then be within the decision aid realm