Every network relies on a central device that creates the network and allows the devices on your network to communicate with each other.

You may want to share an internet connection on your network, or join together a wired Ethernet network and a wireless network. You can add a separate device to your network to perform each of these functions, or you can use a device that combines several functions.
 

Ethernet switch (or hub)	Creates a wired Ethernet network.
Ethernet broadband modem	Connects to the internet.
Ethernet router	Attaches directly to an Ethernet broadband modem and shares the connection on an existing network.
Ethernet broadband modem/router	Connects to the internet, and shares the connection on an exising network.
Broadband modem/router with built-in Ethernet switch	Creates an Ethernet network, connects to the internet, and shares the connection on the network.
Wireless bridge	Connects a wired Ethernet network to an existing wireless network.
Wireless access point	Creates a wireless network, and allows you to connect it to an Ethernet network.
Wireless router (or base station) eg. AirPort Extreme, AirPort Express	Creates a wireless network, and shares the connection from an Ethernet broadband modem.
Wireless broadband modem/router	Creates a wireless network, connects to the internet, and shares the connection on the network.
Wireless broadband modem/router with built-in Ethernet switch	Creates an Ethernet network and a wireless network, connects to the internet, and shares the connection on the network.

Bridging

If you want to add wireless cameras to an existing Ethernet network, you can simply connect a wireless access point to your Ethernet switch. This will give your wireless devices seamless access to the rest of your network.

Wireless routers that have a bridging feature can be used for the same purpose, although in most cases you can’t use them to share an internet connection at the same time. A notable exception is Apple’s Airport Extreme, which has two Ethernet ports so that you can bridge an Ethernet network and share an internet connection on both networks at the same time.

If you are using a wired router and a wireless router on the same network, make sure the DHCP and NAT features are only enabled on the router that connects directly to the internet, as these features will often be enabled on both routers by default.