A LAN is the standard kind of network that you will see in a digital home or office. It consists of one small local sub network, and may have a local router/gateway connecting it to a broader network or the internet.
With WiFi technology, it is possible to use LAN systems for building robots - indeed a few <a a="" brain")="" class="wiki" for="" href="/wiki/microcontroller.html" robot"="" title="A programmable digital controller (or ">microcontroller</a> boards now ship with either a WiFi system or a wired ethernet port for LAN communications. This means you can build communication systems between robots and computers on well known internet protocols.
Time to build your own robot! Using a Raspberry Pi with parts and some time, you can use my book to learn how to make and program a robot with automatic behaviours.