Understanding hosts and nodes

Before offering the definition of a computer network, let us first look at the general definition of a network in order to then recognize the computer network definition. If you search for the word network in the Merriam-Webster dictionary, you will find the following definition: "network is a group of people or organizations that are closely linked and that work with each other." In the same Merriam-Webster dictionary, the phrase networking means "exchange of information or services among inpiduals, groups or institutions." Based on that, the computer network is a group of computers connected to each other in order to share resources. When talking about resources in a computer network, usually the resources can be data, network services, and peripheral devices.

Obviously, when talking about computer networks it is essential to mention components of a computer network because computer networks are ultimately composed of their constituent components. Usually, computers and peripheral devices are just some of the computer network components known to most people. However, there are also intermediary devices and network media.

When talking about hosts and nodes, although their first impression might drive us towards thinking that they are the same thing, in fact they are not! The difference between hosts and nodes is that, while all hosts can be nodes, not every node can act as a host. Because every host is assigned an Internet Protocol (IP) address (see the IP addressing and subnets section for more on IP addresses). There are some nodes such as hubs, bridges, switches, modems, and access points that have no IP address assigned, but are still used for communications. So, a host is any device that offers networking resources to any other node and user on the network. In contrast, a node is any device that can generate, receive, and transmit the networking resources on the computer network. Based on that, Figure 1.1 represents a computer network with hosts (servers, printer, PC, laptop) and nodes (switch).