While learning about network devices can be fun, I know first hand that it can also be a pain in the a%$. With the sizable list of devices that include routers, switches, firewalls, access points etc, coupled with different configurations and sub-types, it is definitely a little intimidating when you are first starting out. I am going to focus on some of the most commonly used network devices that you will see in the wild. Although all of these devices are different and serve separate functionalities, it is common to see a few of them merged into one device.
Routers
Routers are used to route traffic between IP subnets. The way that Routers actually determine where to send the data, is by looking at the IP address attached to the data packets. The IP address will tell the router what the next “hop” will be in its journey to the final destination. When trying to understand how routers work, I have found it most helpful to think of them as air traffic controllers and the data packets as the planes. All airplanes have a set route and destination. They also need to be guided there as quickly and efficiently as possible. Just as air traffic controllers ensure that planes make it to their destination safely and efficiently, routers play that same exact role for the data packets.
In order for a router to connect to a local area network, it needs to connect to a device called a modem (I will explain in more detail what a modem is later in the post). Whether you have a wired or wireless router, you will be connecting to the modem via an Ethernet cable. In addition to wireless and wired routers, there are other types such as core routers, edge routers, and virtual routers that all serve unique purposes. These are more commonly found in larger scale networks.
Modem
It is very common to think of a router and a modem as the same thing. They are not. A modem is a device that connects your home to your ISP (internet service provider). In other words, it brings the internet to your home. This device receives signals from your ISP and translates them into signals that your local devices can use. Some key characteristics of a modem are that it has a public IP address, it uses a wide area network, and it brings internet to your home.
I think it is important to highlight the differences between routers and modems because traditionally they have been two separate devices that worked together to form a home network. A router forms networks and manages the flow of data within those networks, while the modem connects those networks to the internet. With advances in technology, it is common to see these devices merged into one. We call this device a gateway.
Switches
A Network switch connects devices within a network, thus enabling them to talk to each other. Switches are typically a physical hardware device that can manage both software based networks and physical networks. Taking a look at the OSI model, switches operate on the data link layer (layer 2). Within a LAN (local area network), and while using ethernet, a switch forwards all traffic based on a device’s MAC address. Switches are a very valuable tool used In the IT space.
Now there are MANY different types of switches. The main two types it is good to focus on are managed and unmanaged switches. Managed Switches are typically found in offices or large organizations. Managed switches allow the user to adjust each port on the switch. This allows the user to then make configuration changes if needed. Unmanaged switches in my eyes are kind of useless. However they do serve a function. Unlike its cooler older sibling the managed switch, unmanaged switches have very few configuration options.
- It is important to note that a network switch forwards data packets between groups of devices in the same network, whereas a router forwards data between different networks.
Access Points
If you’re like me, then you’ve asked yourself why your able to have such a strong wifi connection all throughout your school or office building even though the router may be hundreds of feet away in a centralized location. The answer to that simple question is that a network device by the name of an access point was being used. Access points are network devices that allow wireless-capable devices to connect to a wired network. You may sometimes see access points referred to as WAP or Wireless Access Point but it is important to know that they are essentially the same thing.
Within an office setting, it is much easier to install access points to connect all computers or devices in your network than to use wires. Another common use of access points would be to act as an “extender” to the wifi connection. Shifting back to the school setting example, you may see access points in each classroom to ensure that devices in those rooms will still have a strong wifi connection, even if they are further away from the main router.
Firewalls
Firewalls are probably the most widely known networking device out there. They are a network security device that monitors traffic within your network. The first line of defense between your network and potential malicious outside traffic! They typically make decisions on what traffic to allow based own IP addresses and port numbers. Most of us have a wifi router/modem in our home which is used to provide internet from our ISP. That device right there is more than likely acting as a physical firewall as well as a router. As an added layer, most computers running MacOS or WindowsOS have a software based firewall running as well. So in some cases a user is protected by both a physical and software based firewall. Keep in mind this is a very brief overview of this device and that there are many different sub-types of firewalls. I may make a separate blog post in the future that focuses primarily on firewalls.
I understand that there are many more network devices, such as network interface cards, repeaters, and hubs that I did not cover in this post. THEY MATTER! And I acknowledge that.
Mak Hurst 