Setting up an infrastructure mode network requires at least one wireless access point (AP). The AP and all local wireless clients must be configured to use the same network name (SSID). The AP is cabled to the wired network to allow wireless clients access to, for example, Internet connections or printers. Additional APs can be joined to this network to increase reach of the infrastructure and support more wireless clients. Home networks with wireless routers support infrastructure mode automatically as these routers include a built in AP.
Compared to the alternative of ad-hoc wireless networks, infrastructure mode networks offer the advantage of scale, centralized security management and improved reach. The disadvantage of infrastructure wireless networks is simply the additional cost to purchase AP hardware.