Network Components
Host Roles
If you want to be a part of a global online community, your computer, tablet, or smart phone must first be connected to a network. That network must be connected to the internet. This topic discusses the parts of a network. See if you recognize these components in your own home or school network!
All computers that are connected to a network and participate directly in network communication are classified as hosts. Hosts can be called end devices. Some hosts are also called clients. However, the term hosts specifically refers to devices on the network that are assigned a number for communication purposes. This number identifies the host within a particular network. This number is called the Internet Protocol (IP) address. An IP address identifies the host and the network to which the host is attached.
Servers are computers with software that allow them to provide information, like email or web pages, to other end devices on the network. Each service requires separate server software. For example, a server requires web server software in order to provide web services to the network. A computer with server software can provide services simultaneously to many different clients.
As mentioned before, clients are a type of host. Clients have software for requesting and displaying the information obtained from the server, as shown in the figure.
client PC and a server connected through a cloud symbolizing the Internet
An example of client software is a web browser, like Chrome or FireFox. A single computer can also run multiple types of client software. For example, a user can check email and view a web page while instant messaging and listening to an audio stream. The table lists three common types of server software.
| Type | Description |
|---|---|
| The email server runs email server software. Clients use mail client software, such as Microsoft Outlook, to access email on the server. | |
| Web | The web server runs web server software. Clients use browser software, such as Windows Internet Explorer, to access web pages on the server. |
| File | The file server stores corporate and user files in a central location. The client devices access these files with client software such as the Windows File Explorer. |
End Devices
The network devices that people are most familiar with are end devices. To distinguish one end device from another, each end device on a network has an address. When an end device initiates communication, it uses the address of the destination end device to specify where to deliver the message.
An end device is either the source or destination of a message transmitted over the network.
Click Play in the figure to see an animation of data flowing through a network.
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Intermediary Devices
Intermediary devices connect the individual end devices to the network. They can connect multiple individual networks to form an internetwork. These intermediary devices provide connectivity and ensure that data flows across the network.
Intermediary devices use the destination end device address, in conjunction with information about the network interconnections, to determine the path that messages should take through the network. Examples of the more common intermediary devices and a list of functions are shown in the figure.
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