What Is Ad-hoc Mode in Networking?

Ad hoc networking describes a mode of connecting electronic devices to one another without the use of a central device like a router that conducts the flow of communications. Devices connected to an ad-hoc network, called nodes, each forward data to other nodes.

An ad-hoc network is a local area network (LAN) that requires minimal configuration and can be deployed quickly, usually for specific or temporary needs.

Ad-hoc networking takes its name from the Latin ad hoc, meaning "for this."

An ad-hoc network tends to feature a small group of devices all in very close proximity to each other. Performance suffers as the number of devices grows, and a large ad-hoc network quickly becomes difficult to manage.

Creating Ad-hoc Wireless Networks

To set up an ad-hoc wireless network, each wireless adapter must be configured for ad-hoc mode instead of infrastructure mode, which is the mode used in networks where there is a central device like a router or server that manages network traffic. In addition, all wireless adapters on the ad-hoc network must use the same Service Set Identifier, or SSID, and the same wireless channel number.

Wireless ad-hoc networks cannot bridge to wired LANs or to the internet without installing a special-purpose network gateway.

Ad hoc networks make sense when needing to build a small, all-wireless LAN quickly for a minimum amount of money spent on equipment.

Ad-hoc networks also work well as a temporary fallback mechanism if equipment for an infrastructure mode network, such as a router or access point, fails.

Ad-hoc Network Security

Ad-hoc networks are often secured given their usually temporary or impromptu nature. Without network access control, for example, ad-hoc networks can be open to attacks.

Devices in an ad-hoc network cannot disable SSID broadcasting in the way that devices in infrastructure mode can. Attackers generally will have little difficulty finding and connecting to an ad-hoc device if they get within signal range.

Authentication can help with this, but ad-hoc networks are inherently more vulnerable to security threats.

Learn more about the layout of ad-hoc networks and infrastructure networks.