Wednesday, February 22, 2012

Wi-Fi Direct: what it is and why you should care ?

Wi-Fi Direct: everything you need to know

The world is falling out of love with cables, but the Wi-Fi we know and love isn't always the best way to connect devices.
Wouldn't it be great if you could effortlessly connect Wi-Fi devices without messing around with access points and lengthy passphrases? That's what Wi-Fi Direct promises.

Wi-Fi Direct is a proper standard

It comes via the Wi-Fi Alliance, the global industry association in charge of certifying Wi-Fi kit.

Wi-Fi Direct is Wi-Fi without the internet bit

The idea behind Wi-Fi direct is that simple tasks need simple connections. For example, you might want to print from your laptop or smartphone to a wireless printer, or to share images with someone else in the same room, or to transmit video from your phone to your TV. None of these things requires an internet connection, but they do need to connect - to the printer, or to the other person's hardware, or to the TV. With Wi-Fi Direct, that bit's easy.

Wi-Fi Direct can have the internet bit too

If you have a Wi-Fi router connected to the internet, you can connect to that too.

Wi-Fi Direct doesn't need a wireless access point

Wi-Fi Direct devices can connect to each other without having to go through an access point: they can establish ad-hoc networks as and when required, letting you see which devices are available and choose which one you want to connect to. If that sounds very like Bluetooth, that's because it is.

Wi-Fi Direct uses Wi-Fi Protected Setup

You don't want any Tom, Dick or Harriet to be able to connect to your stuff - for example, you might not want to see what the neighbours are beaming to their TV on your TV - so Wi-Fi Direct uses Wi-Fi Protected Setup [PDF] and WPA2 to prevent unauthorised connections and keep your communications private. There are two ways to establish a connection: with physical buttons - "press the button on gadget X and then the same one on gadget Y", or with PIN codes.

Wi-Fi Direct knows what's nearby

Wi-Fi Direct includes two potentially useful things: Wi-Fi Direct Device Discovery and Service Discovery. Your device doesn't just know there are devices available; if developers have enabled it, your device will know what kind of devices are nearby and what's on offer - so for example if you're trying to display an image, you'll only see devices that you can beam images to; if you want to print, you'll only see devices that are or that are connected to printers. Crucially this can happen before you connect, so you don't waste any time trying to connect so something that doesn't do what you want it to do.

Wi-Fi Direct uses the same silicon

Manufacturers don't need to add extra radios to their kit: the idea is to have Wi-Fi Direct as part of the standard Wi-Fi radio. It's backwards compatible too, so you don't need to throw out your old Wi-Fi-enabled kit.

Wi-Fi Direct is part of DLNA, and Android too

In November, the Digital Living Network Alliance (DLNA) announced that it was including Wi-Fi Direct in its interoperability guidelines, and Google has added Wi-Fi Direct support to Android 4.0 Ice Cream Sandwich (for example it's in the Samsung Galaxy Nexus's networking options). DLNA says it "expects DLNA Certified and Wi-Fi Certified Wi-Fi Direct smartphones to grow strongly through 2016." That could be an awful lot of smartphones.