The Nodes are a technology developed and created by Cybra Tech. It is a network of router beacons that can be used to share information between all military units (The Shield). This network can only be used for military tasks, according to The Government (for civilian purposes, there is CellCom).
The Earth is covered by the nodes in most areas.
Routers can be terrestrial (most are, because they need to be powered by less energy) or orbital (using satellites).