Ethernet
This is the backbone of your network. It consists of the cabling (called "cat 5" cable) and is typically able to transfer data at a rate of 100mb/s (read more about bandwidth). What is not shown here are the hubs and switches that are used to connect computers and other devices together.
Router
This is your network's "air traffic controller." It routes all the data on your network to where it is supposed to go. It also assigns unique network addresses to all the computers (IP addresses). Routers can also hide the computer and devices that connect to it from the outside world (using Network Address Translation - NAT). To people on the Internet ,your entire network looks like one computer (one IP address). This adds another layer of protection to the computers on your network. A router may contain a VPN server and/or a firewall. Read more about hubs, switches and routers.
Wireless Router
This performs the same function as the router, but for computers and devices not wired to the network. There are several different wireless protocols (802.11a, 802.11b, 802.11g). These protocols differ in bandwidth (11mb/s - 54mb/s) and/or radio frequency (2.5gHz and 5gHz). Wireless networks (WLAN) are inherently less secure than wired networks (LAN). It is important to understand how to secure a WLAN. Read more about wireless LAN routers. Read more about wireless LAN routers.
Firewall
This device is called a firewall because it performs the same function as the firewall in your car. The firewall in your car keeps things in the engine compartment from coming into the passenger compartment. The firewall in your network stops bad things from the Internet coming into your network. A firewall is critical for a secure network.
Virtual Private Network (VPN)
Communications across the Internet are inherently insecure. A virtual private network is a secure connection between two computers (VPN server and VPN client) You can think of the connection as a tunnel across the Internet. Only the two computers on the ends of the tunnel can see what is being transported in the tunnel. In the illustration you see the VPN arrow go around the firewall. This is because a firewall can be set up to allow VPN connections to the VPN server (the router in our case) but block other types of connections. The VPN is how you can securely connect to your network from home or while traveling.
Printer
You are probably familiar with connecting a printer up to a computer, but you can also connect a printer to the network. To do this, the printer must be network compatible or you need a print server. The advantage of putting a printer on the network is that you can print from any computer on the network.
