What is an Independent Basic Service Set (IBSS)?

Quick Definition: An Independent Basic Service Set (IBSS), also known as ad-hoc mode or peer-to-peer networking, is a wireless configuration where devices communicate directly with each other without a central device like a router or access point.

In the world of wireless, there are as many different types of configurations as there are use cases—which is to say, quite a lot. Among these options is the Independent Basic Service Set (IBSS), a peer-to-peer wireless mode that serves a unique and niche need when traditional networking infrastructure is unavailable or unfeasible.

Today, we'll dig into this need, how IBSS can help meet it, the pros and cons, and how to deploy IBSS in the wild. While this is an uncommon type of networking, it is an exam topic for your Network+, so pay attention if you're prepping for that cert!

What is IBSS (Ad-hoc Mode)?

An Independent Basic Service Set is an unusual mode of wireless networking where the devices (laptops, tablets, industrial devices, etc.) communicate with each other without a central device, like a router. This kind of network is also commonly called ad-hoc mode, or sometimes might be called peer-to-peer mode. IBSS is a subset of the BSS, or Basic Service Set.

The network created by the devices often has a limited range and is generally for temporary use. Such a need might arise because more complicated networking infrastructure is difficult or impractical to deploy, so a quick peer-to-peer connection is more accessible. Usually, internet access isn't required, so why go through the extra steps just to share some files?

The Importance of IBSS

IBSS is important where the need exists. Remote locations, for example, might lack internet access, so a router isn't as necessary, but users still need to share files between devices easily. 

Field-based military or industrial applications are similar, where the need to quickly connect devices exists without the burden of traditional infrastructure. The ultimate IBSS might be the classic LAN party. Connect a bunch of PCs to a switch in a basement; no routers required. 

If you really want to get old school, think about the classic OG Xbox; IBSS was the perfect solution for an all-night Halo session with your buddies and as many CRT TVs as you could get your hands on. In practice, though, IBSS assumes wireless connections, but the idea is the same.

Key Components of IBSS

IBSS requires only a few components. First, obviously, are the devices participating in the network, which can include laptops, phones, gaming consoles, security system devices, industrial devices or sensors, AV equipment, farming equipment, and the list goes on and on. 

These devices all require some form of wireless adapter to enable communication between them in a peer-to-peer manner, where each device talks directly to the others without an intermediary like a router. Finally, they must share a common communication protocol, a "language" to actually talk. Technically, IBSS falls under the IEEE 802.11 communications standards, which limits us to protocols that we would generally consider as "Wi-Fi." Conceptually, though, Bluetooth file transfers or something proprietary like AirDrop share the same concept and advantages, just a different protocol.

Advantages and Disadvantages of IBSS

Since IBSS doesn't require any infastructure, it's ideal for rapid deployment for devices. It's also extremely cost-effective, assuming you already have your devices deployed. Finally, it's super flexible, as any device can dynamically join or leave the network, and most can start their own separate networks with other devices.

There are some disadvantages, however. The range is usually limited to the wireless capabilities of the device and protocols. Performance and speed can take a substantial hit as more devices join. Lastly, without infrastructure, there is no centralized management to administer the network or ensure it is configured for the best performance. If you explore IBSS with these limitations in mind and work within them, the user and admin experiences are usually very passable.

How to Implement Ad-hoc Networking

Now that we understand what IBSS is, let's dive into what it takes to get it up and running.

Hardware Requirements

The devices you use for the IBSS or ad-hoc network need wireless network adapters, so just about every laptop, smartphone, and tablet will work. For other types of devices (security sensors, industrial devices, etc.), you'll need to consult their documentation. Regardless of the device type, the Wi-Fi adapter must support ad-hoc mode (which they all should to gain IEEE 802.11 compliance).

Software Requirements

Generally, we are concerned with the operating system for running ad-hoc mode, and most modern operating systems support it out of the box. Some, like iOS, can connect to an existing ad-hoc network but cannot create a new one, so do your research and come prepared.

Setup Process

Setting up an IBSS network is always simple, but instructions for each device will vary. For quick reference, here are official help pages for the latest versions (as of the publish date of this article) of macOS, Ubuntu, and Android (although Android has a unique implementation, it's a similar concept). Windows is a little more tricky as Microsoft removed ad-hoc networks with Windows 10, but you use the mobile hotspot feature to achieve the same effect.

What are the Practical Applications of IBSS?

IBSS is not a widely used feature, but its use cases are often invaluable because of special circumstances—for example, emergency or disaster scenarios. Say a flood or earthquake has taken out power, internet, and cellular services in an area. Battery-powered satellite internet is possible but not always quickly deployable. IBSS ad-hoc networks could be used for location tracking, sharing of maps for search and rescue plans, or triage data for field hospitals.

The military has similar applications in situations where deployments are too isolated for traditional internet access. Real-time communications, of course, are vital, but ad hoc networks can also enable drone control and coordination, share SIGINT (signal intelligence) between units in the field, or provide general situational awareness around maps, building layouts, troop movements, etc.

There are plenty of uses of IBSS for general, boring, day-to-day applications as well. Sharing very large files is always annoying, but an ad-hoc network can avoid the use of Dropbox or flash drives (does anyone still carry these anyway?). Local multiplayer gaming, of course, still uses IBSS, and many smart home devices use a form of ad-hoc network for initial device setup.

Ad-hoc vs. Infrastructure Mode

Ad-hoc mode definitely has advantages over infrastructure mode (aka a normal network with a router, internet access, etc.). It's simple, quick, and enables shared data in situations where you need it. When you need quick device-to-device communication, and everyone's close enough together, it's a win

It does have its disadvantages, though, when pitted against infrastructure mode. No internet access is a significant one, as it lacks centralized management, which also brings lax security. If the network is temporary and internet access isn't needed, ad-hoc can still be a good (if not only) choice.

Final Thoughts 

Independent Basic Service Set (IBSS), or ad-hoc mode, offers a quick and dirty way to create a flexible, infrastructure-free network when you need it most. It allows devices to communicate directly with each other without requiring a central access point or router. 

It's ideal not for everyday use, and it has its trade-offs, but it's useful for niche use cases like the ones we've covered. While it's uncommon, it's an excellent trick to keep in your back pocket and good knowledge for your Network+ exam.

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