What Is Infrastructure Mode in Wireless Networking?

Ad-hoc Mode Is the Opposite of Infrastructure Mode

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In computer networking, infrastructure mode is when a network joins devices together, either through wired or wireless means, via an access point like a router. This centralization is what sets infrastructure mode apart from ad-hoc mode.

Setting up an infrastructure mode network requires at least one wireless access point (AP) and that the AP and all the clients be configured to use the same network name (SSID).

The access point is cabled to the wired network to allow wireless clients access to resources like the internet 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 since these types of devices include a built-in AP.

Infrastructure vs Ad-hoc Mode

Compared to ad-hoc wireless networks, infrastructure offers the advantage of scale, centralized security management and improved reach. Wireless devices can connect to resources on a wired LAN, which is common business settings, and more access points can be added to improve congestion and broaden the reach of the network.

The disadvantage of infrastructure wireless networks is simply the additional cost to purchase AP hardware. Ad-hoc networks connect to devices in a peer-to-peer manner, so all that's needed is the device themselves; no access points or routers are necessary for two or more devices to reach each other.

In short, infrastructure mode is typical for long-lasting, more permanent implementations of a network. Homes, schools and businesses do not usually spring for P2P connections used in ad-hoc mode because they're just far too decentralized to make sense in those situations.

Ad-hoc networks are usually seen in short-lived moments where some devices need to share files but they're too far from a network to make it work.

Or, maybe a small operating room in a hospital can configure an ad-hoc network for some of those wireless devices to communicate with each other, but they're all disconnected from that network at the end of the day and the files are inaccessible that way.

However, if you just need a few devices to communicate with one another, an ad-hoc network is fine. Don't add too many though, because one limitation of ad-hoc networks is that at some point the hardware just isn't fit for all of that traffic demand, which is when infrastructure mode is necessary.

Many Wi-Fi devices can only work in infrastructure mode. This includes wireless printers, the Google Chromecast and some Android devices. In those circumstances, infrastructure mode has to be set up for those devices to function; they must connect through an access point.