e capacity on submarine cables has led some organizations to take partial ownership of submarine cable routes. Facebook and Google together own one third of the capacity of a cable route between Hong Kong and California. Microsoft and Amazon also own parts of other submarine cables. Modifications to the electronics connected to fiber-optic cabling on submarine cables are done to increase capacity on submarine cables. Telephone companies transport traffic on core networks between large cities. They additionally carry traffic on middle-mile networks that connect rural areas to on-ramps to the Internet, and on last-mile networks to individual subscribers and enterprises. Upgrading and installing last-mile, edge networks is challenging. Last- mile networks require the most complex cabling, and entail the highest costs. This is because of the large number of individual connections to homes, enterprises, and multi-dwelling buildings. Keeping networks available and operational during national emergencies is a goal of all countries worldwide. Monitoring and managing networks for sustainability and the ability to communicate during national emergencies is a major challenge. Alternate routes, software management of networks, and continuous monitoring are critical in ensuring that vital networks are available when businesses, governments, and individuals need them in emergencies and for conducting day-to-day business. In ever-increasing numbers, people depend on broadband networks to stay in touch, access applications, get news, and participate in electronic communications during day-to-day activities. www.TechnicalPDF.com THE PUBLIC NETWORK All networks including mobile, Wi-Fi and LAN networks have access (edge), metropolitan (backhaul), and backbone sections. Rural areas generally also have middle-mile networks. The structure of public networks can be broken into five categories. The list that follows provides a brief description of each. 1. Last-mile (also referred to as edge, first-mile, or access networks). 2. Metropol