By Eric Geier
Wi-Fi Direct is a standard being developed by the Wi-Fi Alliance, which should be completed and out in the market any week now. It allows two or more Wi-Fi devices to communicate directly without a wireless access point (AP) or wireless router. They could then, for example, share files, print, or sync.
You should note that Wi-Fi Direct isn't intended to replace the traditional wireless AP or router. It's targeted more for mobile sharing. It will let you more easily connect and share when away from the home or office.
Since the Wi-Fi Alliance's announcement of Wi-Fi Direct, many chipset manufacturers have quickly created their own similar peer-to-peer sharing feature. Examples include Atheros's Direct Connect, Intel's My WiFi Technology, and Marvel's Mobile Hotspot. Each should be easily upgradeable to the final specification when it becomes available.
Wi-Fi Direct Devices and Uses
All different types of devices will support the standard. There might be laptops, desktop PCs, mobile phones, digital cameras, gaming systems, projectors, sensors, TVs, displays, headphones, and more.
Wi-Fi Direct has a wide range of uses and applications. You might be able to quickly share photos between Wi-Fi[nd]equipped digital cameras or camera phones, right at the party or event. Businesses could set up temporary networks in the field or at trade shows.
Wi-Fi Direct could also aid in simple file sharing, even if a traditional Wi-Fi network is around. For instance, say a friend comes over and wants to display some photos from his smartphone to your TV. Instead of having to fork over your private encryption password for the traditional network, you could connect the phone and TV directly.
Though newer Wi-Fi devices can become officially Wi-Fi Direct[nd]certified, the technology will be backward compatible with older Wi-Fi equipment. It will use the same frequency bands and radios. Some vendors may choose to release an upgrade of their software or firmware, but it won't be necessary for at least the basic functionality of Wi-Fi Direct.
Comparing Wi-Fi Direct Against Existing Wi-Fi and Bluetooth
Basically, Wi-Fi Direct is a cross between two already existing technologies. It's a more feature-rich, secure, and smarter version of existing Wi-Fi ad-hoc networking, as defined by the IEEE 802.11 standard. One could also say it's a longer range and higher speed form of Bluetooth.
The most important difference between the existing ad-hoc networking and the new Wi-Fi Direct involves security. Ad-hoc networks in most Windows versions can only run WEP encryption, which is crackable and insecure. Wi-Fi Direct will support the latest encryption: WPA2 (AES-CCMP).
Like existing ad-hoc networking, one Wi-Fi Direct device will control and manage the network. However, there will be enhancements to the negotiation of which device will manage the connection. Factors might include power management, number of connections supported, the user interface, and services offered by the device.
Wi-Fi Direct also features an improved discovery method. More information about the Wi-Fi Direct devices and their services will be broadcast to nearby Wi-Fi devices. You then, for example, might be able to see whether printing is available on a certain Wi-Fi Direct device before connecting.
Unlike existing ad-hoc networking, some Wi-Fi Direct devices will be able to connect to a traditional Wi-Fi network at the same time of belonging to a Wi-Fi Direct network. For instance, this could give the whole Wi-Fi Direct network a connection to the Internet.
Wi-Fi Direct also provides better management features over existing ad-hoc networking. For instance, network administrators might be able to configure their APs to possibly turn off Wi-Fi Direct devices and/or configure their parameters, such as the channel. This could, for example, reduce interference between the traditional and Wi-Fi Direct networks.
Wi-Fi Direct devices will operate at the same speeds or data rates and range as current Wi-Fi gear. This maximum of about 200 Mbps at 200 feet is much more than the 3 Mbps at 30 feet with Bluetooth. This means you can share and communicate much faster and farther with Wi-Fi Direct.
Security of Wi-Fi Direct
As mentioned earlier, Wi-Fi Direct will support the latest encryption: WPA2 (AES-CCMP). It isn't totally clear yet, but it's likely that the Enterprise (RADIUS/EAP) mode won't be included, only the Pre-Shared Key (PSK) mode.
The PSK mode is susceptible to brute-force dictionary attacks on the PSK or encryption passphrase. To be fully secure, users must use a long and complex passphrase. However, Wi-Fi Direct might automatically create these passphrases, so it may not even be a concern.
Considerations and Pitfalls of Wi-Fi Direct
Some people say that Wi-Fi Direct provides the same range as regular Wi-Fi; however, this isn't completely true. The client devices themselves will likely have the same transmit power and reach. But there's no wireless router or AP. The overall range of a Wi-Fi Direct network can be much less than traditional Wi-Fi networks, depending upon the placement of the Wi-Fi Direct devices. A wireless router or AP can be placed in a central spot, relaying each client's communications. Wi-Fi Direct networks don't have this.
Though the Wi-Fi Alliance says it is including enterprise management features and that Wi-Fi Direct will be in another security domain, it will likely still create a new security hole in your network.
It isn't clear yet how Wi-Fi Direct will work exactly, but it is very likely that network administrators won't be able to completely control the Wi-Fi Direct feature of their wireless clients. This means a user might be able to knowingly or unknowingly create a Wi-Fi Direct network on their computers and devices, which might open up unauthorized access to that particular device or the entire network.
The Wi-Fi Alliance also says that Wi-Fi Direct will be compatible with existing Wi-Fi gear, even without any software upgrades. However, they should include some fine print here, too.
Given the proposed features of Wi-Fi Direct, devices that aren't upgraded will likely only have basic functionality. This might mean, for example, that only upgraded devices can create or manage Wi-Fi Direct networks. Additionally, it may mean that only upgraded devices will have the enhanced discovery and management features.
Stay Tuned for More Details
Again, the Wi-Fi Direct standard is in the works and should be released any time. Earlier projections estimated that products will start being certified in mid-2010. When it's final, we'll know more specific details.