Galileo is a system of sensor and display nodes interconnected via a CAN bus. The system is modular, and allows any combination of display and sensor nodes to be connected. This allows the deployment to be scaled from a single display and sensor pair performing a single function (such as an engine monitor) to a collection of many displays and sensor modules.
CAN is a highly reliable bus technology that can tolerate failures such as short-circuits. It allows multiple nodes to communicate with one another, and is message-based, so it's well suited to broadcast protocols. Sensors do not communicate with individual displays. Instead, they simply broadcast the data they gather and it is up to the listener to screen for data of interest. This allows multiple displays to perform the same function without conflict or additional workload on the part of the sensors.
Wiring is unfortunately complicated by CAN's sensitivity to signal reflections. The best way to avoid these is to run a single line between the devices, with the devices connected directly to the backbone. So-called "stub" cables (interconnect cables between the device and the backbone) are allowed but not recommended, and in any event this is not a hub-and-star system.
The best cabling method is thus a single cable from point to point throughout the aircraft. Repeaters may be used to allow star-like installations, but Galileo will not employ these because they are overkill; with careful planning this point is not a serious issue. Select your wiring path as early as possible to avoid surprises during installation. Fortunately, disconnecting a device from the bus does not disrupt its operation. Extra connection points may thus be installed at strategic locations, allowing new sensors (or backup sensors) to be installed in the future without cutting existing wiring.