WifiDirect for peer-to-peer communication
October 22, 2009
The Wifi Alliance, the international Wireless LAN standards body has announced work on a specification titles “Wifi Direct” or “Wifi peer-to-peer“, that will allow devices to connect to each other as a Wifi network without the need of an Access Point (AP).
Traditionally, an AP is used to broadcast the SSID of a Wifi network, which is used by Wireless Clients like Mobile phones, Laptops, etc. to connect to that network (provided they have the required credentials). The AP thus forms an important component in the Wifi network environment.
However, with the new announcement from the Wifi Alliance, the Wifi devices will be able to connect to each other directly using the same Wifi technology. Thus two laptops or mobile phones can be connected to each other wirelessly without the need of an AP in between them.
This is a tremendously advantageous situation as it eliminates the “middle-man” (AP) and lets the devices talk to each other directly. This will be similar to connecting two laptops via a single Ethernet cable, except, there will be NO CABLE !!!
Now, there already existed a couple of ways to do this earlier.
One way was to configure the Wifi driver in “Ad-hoc” mode as opposed to the “Infrastructure” mode. This meant that two laptops could connect to each other wirelessly. However, this mode was not present in all devices. As a result, a laptop and mobile phone , or a network printer could not directly talk to each other. Besides, most people are unaware of such a mode and not all wifi configuration interfaces in all the devices exposed this mode. Finally, this mode allows one two laptops to connect to each other. With Wifi Direct, the number of Wifi devices can connect simultaneously to form a single network.
The second method does not serve the same purpose, i.e., it is not used to connect two devices for data transfer amongst them. It is called Wireless Mesh networks. With Wifi Mesh networks, a client is converted into a partial AP, which is able to connect to a AP on the upstream and able to let other clients connect to it in the downstream. Again, this required a speical Wifi mode to be configured in the driver called Wireless Distributed Systems or WDS. One major drawback of this is reduced bandwidth due to the “sharing” nature of the network. With Wifi Direct, the bandwidth remains intact.
Wifi Direct or peer-to-peer technology would come as a direct competition to other industry standard, viz, Bluetooth 3.0, which utilizes the Bluetooth technology for connecting the devices and the 802.11 protocol for data transfer thereby increasing the bandwidth of bluetooth transfers considerably.
With devices recieving certification for this technology sometime in mid-2010, the Wifi Alliance promises to announce the specification as soon as possible “upon completion”.
Personally I think this was long expected. I would have thought peer-to-peer would have been a part of the original 802.11 standards. Oh well ! Better late than never !!