text: Chapter 1
  Figure 1-2. Relationship between the cyberspace network layers
  PHYSICAL NETWORK LAYER
  1-24. The physical network layer consists of the information technology devices and infrastructure in the
  physical domains that provide storage, transport, and processing of information within cyberspace, to include
  data repositories and the connections that transfer data between network components (JP 3-12). Physical
  network components include the hardware and infrastructure such as computing devices, storage devices,
  network devices, and wired and wireless links. Components of the physical network layer require physical