Rally Vertical Pairing best practices

Updated: July 29, 2013

This topic discusses some best practices that you should consider when you develop your Wi-Fi devices.

This information applies for the following operating systems:

  • Windows Server 2008 R2
  • Windows 7

Simple Wi-Fi configuration and boot-to-pairing

In many scenarios, the first thing that a user wants to do with a new Wi-Fi device is connect the user's computer to it. That means the user must configure the device's Wi-Fi settings to connect the device to the user's Wi-Fi network. Also, if the user moves the device to another location or wireless network or if the user's wireless settings change, the device's Wi-Fi settings must be modified so that the device can communicate on the new Wi-Fi network.

The WPS protocol eliminates many consumer complaints about how difficult it is to configure a device's Wi-Fi settings. However, now that WPS makes the actual configuration process simple and easy, consumers are frustrated with how difficult it is to put a device into WPS mode. Many devices place the option to enable WPS mode deep in a menu tree. For some devices it can take 15 or more steps to enable WPS mode. For the typical consumer, this is far too difficult. If the consumer cannot easily place the device into WPS mode, the advantages of the WPS feature are decreased.

Therefore, the device should make entering WPS mode very easy and simple. This can be done by using many methods. You should follow these guidelines when you provide this functionality on your device:

  • The first-use experience must be very simple. For many consumers this is the first Wi-Fi device that they use, so they might not understand Wi-Fi concepts such as WPS mode. Therefore, the device must intelligently and automatically enter WPS mode. This feature is known as boot-to-pairing:
    1. When the device is powered on, it checks for any kind of connectivity, such as USB, Ethernet, or Wi-Fi.
    2. If the device does not detect any connectivity it enters WPS mode. It should at least enter PIN WPS mode, but preferably it should go into both PIN and push-button WPS modes.
    3. The device remains in WPS mode until either connectivity is established, the user cancels WPS mode, or a time-out occurs.
  • The user should be able to cancel WPS mode at any time.
  • The device should include a menu option to disable the boot-to-pairing feature so that, when it is powered on, it does not automatically enter WPS mode.
  • Manually entering WPS mode must be obvious. Either or both of the following methods for entering WPS mode should be implemented:
    • The device should include a simple and obvious button that places the device into a WPS configuration mode when the user presses it. The button should be easily discoverable by a user, and its functionality should be clearly identified.
    • The device should include a menu option that appears on the device's display (if it has one) to enable WPS mode. The menus for the device should be easy to navigate, easy to understand, and no more than two levels deep. For example, an item in the top level of the device’s configuration menu that is called “Easy Wi-Fi Configuration” is good.

Combine PIN and push-button WPS modes

Consumers are not typically knowledgeable about technical protocols. Therefore, we recommend that you do not offer the user a choice between PIN and push-button WPS modes. Instead, perform both WPS modes at the same time. Displaying a message of “Enter PIN xxxx or press the button on your router” is a much better user experience than asking users whether they want to use PIN WPS mode or pushbutton WPS mode.

WPS advertising performance

To minimize unnecessary latencies, Wi-Fi devices should advertise themselves only to access points that have set the Registrar flag. Access points that have set the Registrar flag are actively looking for WPS devices to configure. Skipping access points that do not have this flag set increases the device’s responsiveness in environments that have many access points.

DHCP and automatic configuration of IPv4 link-local addresses

All Wi-Fi devices should support Dynamic Host Configuration Protocol (DHCP) as a way to obtain an IP address. The most common scenarios involve Wi-Fi networks that provide DHCP services. However, there are some scenarios in which DHCP is not available and the device still must be assigned an IP address. Therefore, Wi-Fi devices that support IPv4 should also support automatic configuration of an IPv4 link-local address.

For more information about DHCP and automatic configuration of IPv4 link-local addresses, see RFC 2131 - Dynamic Host Configuration Protocol and RFC 3927 - Dynamic Configuration of IPv4 Link-Local Addresses.

Quick network connectivity

The time between when a device's Wi-Fi settings are configured by using WPS and when the device is connected to a Wi-Fi network and able to announce its presence on the network by using UPnP and/or DPWS should be as short as possible. When pairing Windows with a device, a customer must wait until Windows discovers the device’s presence on the network. Customers become more anxious and more prone to cancel the process, thinking that the device is faulty if they have to wait a long time for Windows to discover the device. Therefore, you should make every effort to minimize this latency.

Use finish-install actions

If the installation of your device installs a driver package that includes additional software, the software should be installed after the device is installed by using a finish-install action. This installs the software that is included in the driver package in an administrative process. The software installation runs with elevated credentials that let it register and install the software and display a user interface.

However, if the installation of the software requires access to network resources, such as the device manufacturer's web site, you should develop an AutoPlay handler and register it by using a co-installer. After the device has completed installation, Windows runs the AutoPlay handler when it detects the arrival of the device's interface.

Related topics

Using Windows Rally Vertical Pairing to automatically install Wi Fi devices



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