With iOS 7, Apple snuck in a very interesting feature that has mostly gone unnoticed: Mesh networking for both Wi-Fi and Bluetooth. It also seems that Google is working to add mesh networking to Android, too. When it comes to ubiquitous connectivity, mobile computing, and the growing interest in the Internet of things, it is not hyperbolic to say that mesh networking could change the fabric of society. But, I hear you ask, what is mesh networking? I'm glad you asked.
What is mesh networking?
One of the most important factors when discussing networking is topology. In basic terms, the topology describes how the various members (nodes) of a network are connected together.
Most small networks (your office, your home) use a star topology (see the image below), with a central node (a switch/router) connected to a bunch of clients (your laptop, smartphone, Xbox, etc.)
The star topology dictates that if one client wants to talk to another (say, you want to send a photo from your laptop to your Xbox), the data must go through the central point (the router).
The Internet, in case you're wondering, because it's such a mess of different networks, is hard to label as a single topology. One proposal says the Internet has a jellyfish topology, with a very densely connected core (backbone links between data centres), and long tendrils that represent the sparsely connected ISPs and last-mile connections. The image at the top of this article shows a map of the Internet that supports the jellyfish concept.
A mesh topology is where each node in the network is connected to every other node around it. So, if you take the home network star topology, but then allow the smartphone, laptop, and Xbox to talk directly to each other, you have a mesh topology.
The image below shows a fully connected mesh topology (left) and a partially connected mesh topology (right). Even in the partially connected mesh, each device can communicate with each other.
Why should you be excited about mesh networking?
The key reason for mesh networking being exciting is because it doesn't require centralised infrastructure. If you turn off your Wi-Fi router, chances are your entire home network would cease to work. If you had a mesh network instead, everything would continue to work just fine (assuming they're still within range of each other, anyway). If you've used Miracast/WiDi to stream video directly from your smartphone/laptop to your TV, then you've already dabbled in mesh networking.
And so we finally get to iOS 7′s mesh networking capabilities, which Apple refers to as Multipeer Connectivity. Google hasn't said a whole lot about its mesh networking efforts, though Sundar Pichai did mention it a couple of times at SXSW last week, in relation to its Android Wear and home automation efforts.
With Multipeer Connectivity, iOS 7 can communicate with other iOS 7 devices without a centralised hub (Wi-Fi router, cellular base station). If you've used AirDrop, you've probably used Multipeer Connectivity. Other than AirDrop, though, this functionality has gone mostly unused – until an app called FireChat hit the App Store this week.
FireChat is basically an app that lets you chat with other FireChat/iOS 7 users. The key difference, though, is that FireChat is fully decentralised and peer-to-peer – so, if you have two iPhones that are in Bluetooth or Wi-Fi range of each other, they can communicate directly, without sending any data through a Wi-Fi router or the Internet. This is obviously rather useful, if you want to communicate privately, or want to transfer sensitive data.
Mesh networking is a game-changer
What's interesting, though, is that iOS 7′s Multipeer Connectivity apparently allows for the chaining of peer-to-peer connections. So, for example, if Alice is connected to Bob, and Bob is connected to Carol, Alice and Carol can send messages to each other. Apparently, according to Cult of Mac, this chain can be indefinitely long – so, you might construct a chain of 10 or 25 or 50 devices. As long as no one device goes out of Wi-Fi range, they can all communicate with each other. Furthermore, if one of those devices has an Internet connection, every other member of the mesh can share that connection. You might imagine using this to extend Internet access to rural or out-of-the-way (underground) locations – but I think installing a few Wi-Fi repeaters is probably a more graceful solution than leaving an iPhone sitting on a chair somewhere.
Still, Apple's inclusion of mesh networking in iOS 7 is an exciting indicator of things to come. For now, it's just AirDrop and apps like FireChat – but tomorrow, it's easy to see how your iPhone, Apple TV, MacBook, and the other Internet-of-Things around your home, will use mesh networking to communicate with each other. Truly decentralised networking, especially if you throw in some cryptography, is one of the most disruptive technologies that you can imagine. If mesh networking takes off and the world's billion smartphones suddenly start chattering to each other, I guarantee that you will see some mind-blowingly killer applications in the next few years.