Network hardware refers to the vast array of physical devices that make up the network infrastructure required to connect and maintain the different types of networks. See below for some examples:
Routers are network gateway devices that can connect two or more networks together. Routers with WiFi antennas that can support wireless connections are known as wireless routers. These routers can store a routing table in their memory that helps them filter data packets so that they can forward the packets to the right network destinations. Routers contain an embedded operating system referred to as firmware. A common use of a router is to connect a home network to the internet. Modern routers now incorporate switches and modems to provide combined functionality and reduce the amount of hardware needed.
Modems are translators that receive a signal from the router and translate it into a signal that can be sent down an internet connection to your ISP. Similarly, when they receive a signal down the internet line they translate it into information that can be understood by the router before passing it on.
Network switches have an important role, they connect the other devices on a network and can store the MAC addresses of those devices so that they can easily filter the passing data packets to understand which device has requested them and then forward the relevant packets to the correct destinations.
Hubs are similar to switches in the sense that they also connect multiple devices on a network. However, they are a much older and much less complex device. They simply broadcast what they receive to every device they are connected to, the theory being that one of the devices will be the correct one. This makes them much less secure than switches as anyone connected can easily receive all hub traffic. Hubs have been largely superseded by switches thanks to the falling prices of switches.
A bridge is a fairly simple device that connects one part of a LAN to another so that the two independent parts work as a single unified LAN instead. Bridges can be useful for scaling a network. Bridges are different from routers and switches as all they do is connect network segments with no manipulation of the data packets passing through them.
Wireless Access Points
A wireless access point, also known as a WAP, Access Point, or WiFi hotspot, is a device capable of utilizing radio frequencies and antennas to allow devices to connect to it wirelessly. This way a WAP can be connected to the router, or even be built into the router, and then people can wireless connect to the WAP so that they can communicate with the router without being restricted to a single location by cables.
Network firewalls are security-focused devices that work as a barrier, monitoring incoming and outgoing traffic and either allowing the traffic through or blocking the traffic based on predefined rules. A firewall can be both hardware based and software based and depending on where they are placed can be used to defend a whole network from connections outside of it, or can be inside the network itself protecting a specific area of it.
A proxy server is the network equivalent of a middleman. Requests can be sent to the proxy server for resources such as web pages. The proxy server will retrieve those resources and then pass them back to the requesting device.
Proxy servers can often be used in place of an external router. The reasons being that as well as typical router functionality they can also have advanced features configured on them such as web traffic filtering, anti-virus software, etc.
While wireless networking can be useful for various reasons network cables are still extremely common in modern networking due to the fact that they can typically transfer data faster and are less accessible for hacking.
Network Interface Card
This incredibly important piece of network hardware exists in all computers connected to a network as the need a network interface card to be connected to a network, these cards are also called NICs for short. Some computers, laptops for instance, have a NIC for wired connections and another NIC for wireless connections built into them already.