The Internet is truly global a national network of millions of computers and various other electronic devices connected via networks. By using the Internet you can access virtually any data, communicate with other people around the world, and perform a variety of other tasks. You are able to do all of that by connecting a personal computer to the Internet which is also known as going online. There are two types of Internet: a private (ISP) network and a public (public) network.
The private network operates in a manner very similar to how a phone line is handled. Private networks operate in their own private network without the knowledge of anyone else on the internet. The way the Internet works is that data packets are sent from one computer to another over the network. Every computer on the internet will receive data packets for transmission through the network by the router. A router is a device that receives, compresses, encrypts, and forwards the data packets for use by computers, usually the computers on a private network.
Another type of the Internet is the public internet network. This is different from the private network in that the data packets for data transmission are allowed into the public network. However, there is no guarantee that the data will be received and if it is it will be unencrypted and therefore subject to capture by other people. This is why you cannot rely solely on the Internet to send sensitive or confidential information over the Internet and why you should protect sensitive information with encryption. This is basically why you need to use a VPN or Virtual Private Network to send sensitive data and information.
The way the Internet works is quite complicated, but we will get into more details below. When you connect to the Internet, you are actually passing through multiple layers of security before actually reaching the application you want to use. Every time you connect to the internet you are passing through many different types of networks around the world. Each of those networks encrypt the incoming data packets before passing them on. If an unscrupulous person wanted to intercept your packets, they would have to know what the network was, what IP address belongs to, and what protocol is used to encrypt those packets.
However, an even more secure way of passing data is the technology known as tunneling. Tunneling allows two computers to connect to the internet at the same time over a wide area network (WAN). Because the computers are so close to each other, no one can break the data encryption that is in place between the two computers. Because of the WAN nature of the Internet connection this is extremely secure and prevents someone from intercepting your data packets either. While you probably do not need to worry about this with email, you might want to use a VPN for secure file sharing if you use the internet frequently or simply share sensitive information with friends and family.
All Internet communication goes through the packets that are sent and received by every computer. A lot of wireless routers are designed to allow you to access the internet with a smart phone, laptop, or desktop. Because of the way the packets are transmitted and received, an iPhone will be able to send and receive data packets while an iPad would not. Therefore, even if you are not connected to a WAN, you can still use the internet to get everything done without having to use a laptop.