A local area network is a computer network that covers a small geographic area, such as a residence, an office, or a group of buildings.
Smaller LANs generally consist of a one or more switches linked to each other, where one switch is usually connected to a router, cable modem, or DSL modem for Internet access.
There are many ways to wire up a LAN network, but the most widely used is the Ethernet interface.
Ethernet over unshielded twisted pair cabling and wirelessly via Wi-Fi are the technologies most commonly used with LAN networks. Ethernet is generally preferred for direct control of AV components.
When you connect Ethernet units to a network, be aware that just because two units have Ethernet does not mean they are automatically able to communicate. Ethernet is strictly a hardware connection standard. This means that it only specifies the hardware connection between units and not what protocols that are transmitted over the connection. However, it is likely that most modern units you encounter will use an IP (Internet Protocol) connection. Ethernet therefore specifies the hardware connection, along with the speed that the units use to communicate between each other. The IP specifies the protocol used to route data through an Ethernet connection.