The first philosophical question of the day is: what is a network? Well, a network is nothing more than a collection of connected devices and end points and end systems with the purposes of exchanging and sharing information.
Now, today the network is a collection of devices and end systems, but those end systems include almost anything, not only computers, servers, but also telephones and cell phones and industry-automation machines that will now be involved in the exchange of information. That means we are exchanging not only data or traditional data in the form of files and other components, but also voice and video and multimedia collaboration. Another important piece is the scope of the network. If you think of the Internet, then there are networks everywhere. You also can think of the mobile user working from home, being connected and networked. The hierarchy is completed with teleworkers, home offices, branch offices, headquarters, and again, the Internet as a global network that interconnects us all.
Today’s network follow a hierarchy that kind of resembles human interaction and human organizations, so as you have people living in houses which comprise streets, which then are grouped into cities, and then from there to county, states, countries, etc., you also have PCs that are interconnected by switches, which in turn are interconnected by routers. As you look at the physical connection between these devices that form the hierarchy, you find the major components. So PCs are end systems; but again, IP phones are also end systems, and automation machines are end systems. Soon enough, your coffee maker will be an end system. Those end systems will be interconnected by switches, which provide the network attachment plus intelligent switching of information. In that interaction, you will see cable or wired and wireless media to connect the machines into the switch. You will also see components like the network interface card to provide networking to the end system, and also connecters to connect the media into the interface card. Routers will be there to connect network of switches and to provide the best path from network to network.
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