HPE Aruba - Campus Access Associate - Networking Fundamentals - What is a network?

What is a network?

To begin exploring the world of network engineering, we first need to define a computer network. At its core, a computer network is a group of hosts connected using communication media to accomplish a task. A host is defined as any device connected to the network, such as a computer, server, laptop, printer, IoT sensor, etc. A task could be file sharing, printer sharing, internet browsing, etc. The communication media could be physical cabling such as copper wire or wireless medium such as WiFi or Microwave (not the one in your kitchen). A network is comprised of both hardware and software components that work in tandem to allow the transport of data between hosts. We will dig into those components in more detail later. Key Point: The fundamental purpose of a computer network is to share resources or information.

The most common or well-known example of a computer network is the Internet, which connects users worldwide. But let’s keep things simple to start.

In your house, you more than likely have a cable modem or router provided by your internet service provider that allows you to connect your devices to the Internet. The devices in your home make up the simplest version of a Local Area Network (LAN). A LAN is a group of devices physically located in the same location. A LAN is not limited to a small deployment like your home. A LAN could also be a large campus network at a university or a campus network at a local business. The key concept with a LAN is that the devices are grouped at a single location.

In today’s world, most devices need to be able to connect to devices in other physical locations. A Wide Area Network (WAN) provides connectivity over large geographical distances. The Internet is an example of a WAN. There are several ways to connect LANs to form a WAN. WAN technologies include Private Dark Fiber Optic cabling, Metro-Ethernet, Satellite, Broadband Cable, Cellular (4G/5G), and Internet Service Provider Fiber Optic Cabling. Enterprise networks will use one or more of these WAN technologies to connect their corporate locations to different physical locations. It is common for large enterprise networks to have multiple WAN technologies available at each site for redundancy. A site may have Metro-Ethernet as its primary connection, Cellular 5G as a backup connection, and Starlink Satellite as a tertiary connection.

There is a third network type that isn’t used as often. Metropolitan Area Networks (MAN) refer to networks that cover an entire city. In my 20+ years of working in computer networking, I have never heard anyone use the acronym MAN. Most engineers refer to the network on a physical site as the LAN and any network that provides connectivity to other sites as the WAN.

The last network type you may encounter is the Personal Area Network (PAN). A PAN is typically restricted to a user and its immediate workspace and can use wired or wireless technologies for connectivity. USB, Bluetooth, Zigbee, and IrDA (infrared) are common communication media used in PANs.

Now that we know what a network is, we can dig into how they work. See you on the next post.