Network building blocks

Network building blocks

Now let’s look at these building blocks

A switch connects endpoints to the network so they can communicate with each other. It also has the additional capability of momentarily connecting the sending and receiving devices so that they can use the entire bandwidth of the network without interference.

When they’re deployed properly, switches improve the performance of the network by reducing the collisions which occur when two devices try to communicate on the same channel at the same time.

They have two primary benefits:

  • They provide each pair of communicating devices with a fast connection.
  • They segregate the communication so that it doesn’t enter other areas of the network.

A network comprising devices connected by switches is often referred to as a local area network, or LAN.

Routers are devices that connect two or more networks and filter network traffic so that only the desired information travels between them. For example, routers can be used to regulate the flow of information between internal networks and the Internet.

The portion of a network connected by routers is often referred to as a wide area network, or WAN.

Most applications that use a network employ a client / server model.  Server software running on one device listens for requests from client software running on another device. The client initiates the connection, and the server supplies a service to the client.

Proxy servers act as a firewall and web filter, provide shared network connections, and cache data to speed up common requests. A good proxy server keeps users and the internal network protected from the bad stuff that lives out in the wild internet. Lastly, proxy servers can provide a high level of privacy.

A proxy server is a computer on the internet with its own IP address that your computer knows. When you send a web request, your request goes to the proxy server first. The proxy server then makes your web request on your behalf, collects the response from the web server, and forwards you the web page data so you can see the page in your browser.

When the proxy server forwards your web requests, it can make changes to the data you send and still get you the information that you expect to see. A proxy server can change your IP address, so the web server doesn’t know exactly where you are in the world. It can encrypt your data, so your data is unreadable in transit. Lastly, a proxy server can block access to certain web pages, based on IP address.

So, a Proxy can do many things:

  • Control internet usage of employees.
  • Improve bandwidth and speeds.
  • Provide privacy benefits.
  • Provide better security.

Diagram featuring, Switch, Router and Proxy server.

Figure 1: Network building blocks

What's next?

So, you've seen the three main building blocks of a network. Now you're going to explore how the network security of an organisation can be controlled and protected by a perimeter defence. This involves different elements, such as firewalls and boundary controls, to defend the network.


In this course you’ll take a deep dive into networks and communications controls, looking at Firewalls, DMZ and VPN among others.

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