In computer networking, infrastructure mode allows a network to join devices together, either through a wired or wireless connection, using an access point such as a router. This centralization sets infrastructure mode apart from ad hoc mode.
Infrastructure Mode Network Requirements
Setting up an infrastructure mode network requires at least one wireless access point (AP). The AP and clients must be configured to use the same network name.
The access point is cabled to the wired network to allow wireless clients access to resources such as the internet, printers, and some peripheral devices. APs can be added to this network to increase the reach of the infrastructure and support more wireless clients.
Home networks with wireless routers support infrastructure mode automatically; these types of devices include built-in APs.
Infrastructure vs. Ad Hoc Mode
Compared to ad hoc wireless networks, infrastructure mode offers the advantages of scale, centralized security management, and improved reach. Wireless devices can connect to resources on a wired local area network (LAN), which is common in business settings. More access points can be added to improve congestion and broaden the network's reach.
The disadvantage of infrastructure mode wireless networks is the additional cost of AP hardware. Ad hoc networks connect to devices in a peer-to-peer (P2P) manner, so only the devices themselves are needed. No access points or routers are necessary for two or more devices to connect to each other.
In short, infrastructure mode is typical for long-lasting or permanent implementations of a network. Homes, schools, and businesses do not usually use the P2P connections used in ad hoc mode because they're too decentralized to make sense in those situations.
Ad hoc networks usually exist in short-lived moments in which some devices need to share files but are too far from a network to work. A small operating room in a hospital might configure an ad hoc network for some wireless devices to communicate with each other, but they're all still disconnected from that network, and the files are inaccessible.
If just a few devices need to communicate with each other, however, an ad hoc network will work fine. One limitation of ad hoc networks is that, at some point, the hardware won't be able to accommodate the traffic. That makes infrastructure mode necessary.
Many Wi-Fi devices work only in infrastructure mode. These include wireless printers, Google Chromecast, and some Android devices. In those circumstances, set up infrastructure mode to enable those devices; the devices themselves must connect through an access point.