Let's go back in time, when networks didn't exist as they do today. If I wanted to give somebody a file to review my work, I would have to take that file, save it to a floppy disk, and give this disk to the other person. It might sound cumbersome, but this was the only way to collaborate and move data around. What exactly is a network? Let's find out what it is and how we can build one.

A network, by definition, can be any size and any variety of devices that interconnect. When we talk about a network, we are referring to all the different devices and operating systems that exchange data and communicate with each other. Modern networks have the ability to transmit data between dissimilar networks. That means that the platform you use is not as important as it used to be. Nowadays, people who use Microsoft Windows, people who use UNIX-based platforms, people who use Apple Macintosh, along with everybody else out there, can all intercommunicate because they have common protocols or common core set of communication languages.

Every network has physical (hardware) and logical (software) components. The physical components or intermediate systems are switches, routers, firewalls, and the actual media itself. Switches contain many ports and are used as a connection point for all other devices in a network. When a piece of information (packet) is introduced to a port, switches try to find the best outgoing port for that packet. Routers relay these packets from one network to another. Firewalls protect the network from any kind of cyber-attacks, by filtering and controlling the traffic that comes inside a home or office network. All these devices mentioned use several types of cables and/or radio frequencies when they transfer any kind of data, like emails or an audio file. Also, every computer uses a media access component (network interface cards) to be able to connect with a switch or a router.

One of the benefits of having a network is recourse sharing - the interconnectivity we talked about earlier. A centralized service, like a print server or a file server, handles the traffic we generate and ensures simultaneous availability of resources. Restrictions on sharing resources, based on the user, computer or application, can be applied, increasing the network's security and regulating users' behavior. Over the past few years, we have seen a huge increase in network storage, the systems that store up to terabytes of information. Network storage has become a resource that everybody can access, along as the administrator allows it.

As network features continue to grow, applications become more and more sophisticated and make the most of these new network technologies. Excellent examples are VoIP (Voice over IP) programs that someone can use to make regular phone calls, without having to use a physical (and much more expensive!) land telephone line. That is why, one of the first questions engineers ask, when they are designing a network, is what applications need support. This really determines how engineers will design these networks.

Unfortunately, there is a drawback in modern networks: safety. No one is implying that all networks are not secure, but when we share something on a network we are definitely exposing that information to dangers. There are lots of things that one can do to protect their valuable information, of course. One is using strong passwords (take, for instance, the classic "P@ssW0rd$") or encrypt data using special software.

Without networks, the Internet would not exist. However, we should be very careful when we are sharing something. Even with the security dangers, though, networks are beyond any doubt today's demanding computer users' biggest tool.