Defense Information Infrastructure. The shared or interconnected system of computers, communications, data applications, security, people, training and other support structures serving DoD local, national, and worldwide information needs. DII connects DoD mission support, command and control, and intelligence computers through voice, telecommunications, imagery, video, and multimedia services. It provides information processing and services to the subscribers over the Defense Information Systems Network and includes command and control, tactical, intelligence, and commercial communications systems used to transmit DoD information. (Pending approval in JP 1-02).