In certain scenarios users of Windows 7 and Windows Vista can experience problems when connecting their mobile computers to some Wi-Fi hot spots. According to Microsoft, symptoms will vary, and can include poor performance as well as having the wireless network connection dropped altogether. The Redmond company revealed that these issues are also associated with mobile machines which are running on battery power. The software giant noted that customers running Windows 7or Vista mobile PCs and connecting them to wireless access points (AP) also reported these issues.
“This issue occurs if the Wi-Fi hot spot uses wireless APs or routers that do not support the 802.11 power save protocol,” Microsoft informed. Still, the power saving features built into both Vista and Windows 7 by default, contribute to this problem. Essentially, when a Windows 7 mobile PC is plugged into a power source, the wireless network adapter will go into Maximum Performance mode and switch off 802.11 power save mode. At the same time, for Windows 7 machines running on battery power, the wireless network adapter will go into Medium Power Save mode, which is associated with the 802.11 power save mode.
“When an 802.11 wireless network adapter that is set to use power save mode wants to enter a sleep state, the adapter indicates this intention to the wireless AP. The adapter does this by setting the power save option in its packets or in the 802.11 frames that it sends to the wireless AP,” Microsoft informed.
“If the wireless AP does not support this feature correctly, the wireless AP continues to send packets to the client network adapter even if the client network adapter radio is turned off. Therefore, these packets are lost. In this scenario, the symptoms that you experience may vary depending on the phase of the wireless connection in which these packets are lost,” the company added.
Microsoft offers three methods for end users to manually correct problems:
“1. Connect the mobile PC to a power source – When you plug the mobile PC into a power source, Windows Vista or Windows 7 switches the wireless network adapter power setting in the default power plan from the Medium Power Save setting to the Maximum Performance setting. This turns off the 802.11 power save mode.
2. Modify the default power saving power plan – Modify the default on-battery power setting for the wireless network adapter. Configure the wireless network adapter to use the Maximum Performance setting when Windows Vista or Windows 7 is configured to use the Balanced power plan or the Power saver power plan. To do this, follow these steps:
- Click Start, type Power Options in the Start Search box, and then click Power Options in the Programs list.
- If you are prompted for an administrator password or confirmation, type your password or click Continue.
- Click Change plan settings under the power plan that is selected. For example, if the Balanced option is selected, click Change plan settings under Balanced.
- Click Change advanced power settings.
-In the Power Options dialog box, expand Wireless Adapter Settings, and then expand Power Saving Mode.
- In the list that appears next to On battery, click Maximum Performance, and then click OK.
3. Use the “High performance” power plan – If the computer is running on a power plan other than the High performance power plan when you connect to a wireless network, manually change the power plan to High performance. To do this, follow these steps:
Click Start, type Power Options in the Start Search box, and then click Power Options in the Programs list.
If you are prompted for an administrator password or confirmation, type your password or click Continue. Note: You can also right-click the battery icon in the notification area to access the Power Options command.
Click High performance.”