Network Technology

The Department of Defense (DoD) maintains one of the largest computer networks in the world. The network follows DoD personnel across the globe collecting, transferring and processing information in forms as diverse as data warehouses, in-the-field mobile devices and mission computers on board F-18’s. This network is also constantly changing in size and shape as new missions are undertaken and new technology is deployed. In military terms, that means the cyber terrain of the DoD network is constantly shifting.

In areas lacking trustworthy communications infrastructure, deployed servicemembers rely on wireless devices to perform double duty: they not only provide access to the network; they are the network. Protocols for these networks require nodes to coordinate among themselves to manage resources, such as spectrum and power, and determine the best configurations to enable sharing of information. A problem with these protocols is that they implicitly trust all information shared about the security and operational state of each node, and the network as a whole. Consequently, inaccurate control or security information can quickly render the network unusable. This shortcoming could put productivity and mission success at risk as use of military wireless systems increases.

Troops operating in forward locations without telecommunication infrastructure often rely on a mobile ad hoc network (MANET) to communicate and share data. The communication devices troops use on foot or in vehicles double as nodes on the mobile network. A constraint with current MANETs is they can only scale to around 50 nodes before network services become ineffective. For the past 20 years, researchers have unsuccessfully used Internet-based concepts in attempts to significantly scale MANETs.

Air-ground fire coordination—also known as Close Air Support or CAS—is a dangerous and difficult business. Pilots and dismounted ground agents must ensure they hit only the intended target using just voice directions and, if they’re lucky, a common paper map. It can often take up to an hour to confer, get in position and strike—time in which targets can attack first or move out of reach. To help address these challenges, DARPA recently awarded a contract for Phase II of its Persistent Close Air Support (PCAS) program to the Raytheon Company of Waltham, Mass.

The intensity of light that propagates through glass optical fiber is fundamentally limited by the glass itself. A novel fiber design using a hollow, air-filled core removes this limitation and dramatically improves performance by forcing light to travel through channels of air, instead of the glass around it. DARPA’s unique spider-web-like, hollow-core fiber, design is the first to demonstrate single-spatial-mode, low-loss and polarization control—key properties needed for advanced military applications such as high-precision fiber optic gyroscopes for inertial navigation.