Understanding Ad-Hoc Mode in Networking

Ad-hoc networks are local area networks that are also known as P2P networks because the devices communicate directly, without relying on servers. Like other P2P configurations, ad-hoc networks tend to feature a small group of devices all in very close proximity to each other.

Wireless ad-hoc networking describes a mode of connecting wireless devices to one another without the use of a central device like a router that conducts the flow of communications. Each device connected to an ad-hoc network forwards data to the other devices.

Because ad-hoc networks require minimal configuration and can be deployed quickly, they make sense when you need to put together a small — usually temporary — cheap, all-wireless LAN. They also work well as a temporary fallback mechanism if equipment for an infrastructure mode network fails.

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Ad-Hoc Benefits and Downfalls

Ad-hoc networks are obviously useful but only under certain conditions. While they’re easy to configure and work effectively for what they’re intended for, they might not be what’s needed in some situations.

What We Like

• Without the need for access points, ad-hoc networks provide a cheap means of direct client-to-client communication.

• They are easy to configure and provide one of the best ways to communicate with nearby devices in time-sensitive scenarios when running cable is not an option, such as in emergency medical environments.

• 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.

• When the number of devices on the ad-hoc network is relatively small, performance might be better than when more users are connected to a regular network.

What We Don’t Like

• 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.

• Performance suffers as the number of devices grows in an ad-hoc setup, and it becomes increasingly more difficult to manage as the network grows larger.

• Devices can’t use the internet unless one of them is connected to the internet and sharing it with the others. If internet sharing is enabled, the client performing this function will experience massive performance problems, especially if there are lots of interconnected devices.

• Managing an ad-hoc network is difficult because there isn’t a central device through which all traffic flows. This means there isn’t a single place to visit for traffic stats, security implementations, etc.

There are a few other limitations of ad-hoc networks that you should be aware of before you set up this type of network.

Requirements for Creating an Ad-hoc Network

To set up a wireless ad-hoc 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 the traffic.

In addition, all wireless adapters must use the same Service Set Identifier (SSID) and channel number.

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