Feldmayer radios the tank at the rear of his patrol and orders it to the front of the convoy. It's the latest M1A2 Abrams, one of the most advanced tanks in the world, equipped with new night-vision sensors, thicker armor and BFT's older (and, counterintuitively) more feature-packed cousin: Force XXI Battle Command Brigade-and-Below, or FBCB2. First built in the early 1990s for Cold War-style conflicts, where armies are tightly bunched together, FBCB2 relies on a classified radio band to communicate. BFT, designed later for more-dispersed, unconventional warfare, uses more-open satellite transmissions; troops can share information at greater distances, but they can't get the kind of secrecy that FBCB2 provides. The Army is working on a bridge between the two systems so that they will be able to share some basic information, but for now they are mostly incompatible. Feldmayer won't be able to see where the tank is leading them, and he won't be able to use FBCB2's Instant Messenger-like tool to quickly relay commands. He won't have access to any of the communications links that increase what the Pentagon calls "situational awareness" and that ultimately power network-centric warfare. If the navigation systems were working, every vehicle could split up or speed ahead if an attack came, without getting lost. But today they will all have to follow the tank's taillights in a neat line, just as it was done in 1944.