What are the basic examples of a global network?
A global network is a wide area network (WAN) that covers the globe—which, when it comes to network size, is about as wide as you can get.
Computers on a global network can be linked wirelessly or maintain a wired connection, although, for a truly global network to be wired, some of its cables have to stretch underwater. Predictably, these underwater cables are more expensive and harder to fix than underground cables.
The internet is the biggest and most basic example of a global network; it connects smaller local area networks, or LANs, all over the planet. Businesses with international offices and clients have their own global networks, as well, that connect their various locations and services together.
Multinational companies with global networks, like Cisco, for example, face a unique set of challenges in keeping everybody connected. Because they cover so much ground, and cross so many borders, they have to deal with different service providers and government regulations in each of the countries in which they operate.
A common working definition for "global network" is the following definition: A global network is "any communication network that spans the entire Earth." If you use this definition, then a global network is going to be something like the GSM mobile communication system. GSM stands for "Global System for Mobile communications." Currently, GSM networks are available in 219 countries and allow individuals to be contacted via the same mobile number in each of those countries. GSM networks cover more than 90% of the world's population. The GSM network for cellular communication is a solid, specific example of a global network. It allows communication between individuals and groups from just about any location on the planet. Another example is the Internet, but I feel that is a much more vague example.