How Windows Vista RTM Build Addresses Wireless Connectivity Issues

How Windows Vista RTM Build Addresses Wireless Connectivity Issues

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Wireless access is a key feature in Windows Vista, and it needs to work as reliably as possible for users.  In the final version of Windows Vista, the default power setting for 802.11 wireless adapters was changed to “Maximum Performance” to offer seamless wireless access experience and solve connectivity issues with certain access points. Users and OEMs can change the setting value to deliver additional power savings, if they want to further extend the battery life.

Context

Test results from Microsoft and our customers show that some Windows Vista beta users experienced connectivity problems when connecting to public WiFi hotspots.  In many cases, the root cause of the problem is access point or router hardware which is not compatible with the 802.11 power save protocol.  The symptoms of the problem are either failing connections or extremely poor connection performance and throughput.  Typically, these problems are experienced only when the computer is on battery power—connecting to AC power solves the issue.

By default, Windows Vista enables many platform power management features, including wireless adapter power saving modes.  On all Windows Vista systems, the default power plan is Balanced, and pre-release versions of Windows Vista enabled Medium Power Savings for the 802.11 wireless adapter when the computer is on battery power.  When the computer is on AC power, Maximum Performance (no power savings) is enabled for the 802.11 wireless adapter.   This explains why connecting to AC power solves the connectivity issue for many users, as did changing the power plan to High Performance or changing the wireless adapter power setting to Maximum Performance in Power Options.

When power save mode is enabled for an 802.11 wireless network adapter, the adapter periodically enters a low-power state where the radio transmitter and receiver are in “sleep” mode.  The wireless adapter in the computer (client adapter) indicates the “sleep” mode by setting the power save option in its packets or 802.11 frames sent to the access point. The access point receiving frames with the power save option set determines that the client adapter wishes to enter power save mode, and begins buffering packets for the client adapter while it is asleep. The client adapter’s radio periodically wakes up and communicates with the access point to retrieve the buffered packets. This scheme enables the wireless adapter to consume less power by sleeping and waking periodically, just at the right time to receive network traffic from the access point.

However, this power savings scheme for 802.11 wireless adapters depends on cooperation of the access point.  The problem is that many access points do not implement or support the power save feature correctly.  Some broken access points keep sending the packets to the client—even when the client adapter’s radio is asleep.  The packets sent to the client radio while it is asleep are lost, which leads to the connectivity, performance and throughput issues that some Windows Vista beta users were encountering. 

Wireless access is a key feature in Windows Vista, and it needs to work as reliably as possible for users.  In the final version of Windows Vista, the default power setting for the 802.11 wireless adapter is “Maximum Performance”.  This means, that by default, on battery power or on AC power, wireless adapters will not use power-saving modes.   OEMs are able to change any power setting when they are building systems with Windows Vista, so the setting might be different on a machine released with Windows Vista.  The obvious downside to the power setting change is a potential decrease in computer battery life.  But, it may be difficult to diagnose the root cause of the wireless connectivity problem, so the wireless power setting was changed accordingly for the most common default case.

If you want to re-enable power savings for your 802.11 wireless adapter, you can easily do this in Windows Vista.  There are two primary ways:

  • Change the wireless power saving setting:
    • Open Power Options in Control Panel
    • Choose Change Settings for the current power plan
    • Choose Change Advanced Power Settings
    • Expand Wireless Adapter Settings
    • Expand Power Saving Mode
    • Choose Maximum Power Saving, Medium Power Saving, Low Power Saving to enable various levels of 802.11 power save modes.
  • Choose the Power Saver power plan:
    • Click on the battery meter on the desktop and choose Power Saver.
    • The Power Saver plan has 802.11 power saving mode enabled for both battery and AC power.

Microsoft is committed to both seamless wireless access and extended battery life.  We are actively working with industry partners to fix wireless access points so they work correctly with 802.11 power save mode. 

===================

UPDATE

I have seen a few articles written over the past few days regarding this post. Most seem to be focusing on the sentence that said the change made to default wireless settings could result in a “potential decrease in computer battery life.” I want to clarify that even with the wireless power management feature turned off for there should be no noticeable difference in battery life than what you get with Windows XP today; the native wireless power management feature is new in Windows Vista, and is therefore an added bonus to people’s overall battery life experience when in use. (Ars Technica got it right.)

 

The true intent of the post was to let our beta testers know that we made connecting to wireless access points more reliable in the final version of Windows Vista. As I wrote in the original post, We are actively working with industry partners to fix wireless access points so they work correctly with 802.11 power save mode, and in the meantime we’ve optimized Windows Vista to deliver the best wireless experience possible.

 

21 Comments
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  • Mobile
    28 Posts

    well Jieznek you have shared a very vital info with us! i appreciate it.

  • Duane Duane
    52463 Posts

    hi all, i have a very strange problem with my CR vaio laptop.. whenever i switch the power plan to balanced plan or if i boot the laptop with balanced plan, after awhile there will not be any audio. this problem doesnt come out if i am using the high performance plan.

    anyone know how to solve this?

  • Duane Duane
    52463 Posts

    I have vista and have been using wireless with no problem until 3 weeks ago. Now, even though I have excellent signal strength, I cannot get access unless I am 3 feet from the router. the XP machines in my house are not having this problem.  What could have possibly changed.  I have only had this computer since August 08.

  • Hello, I hope this is the correct place to ask for help for my laptop.  I bought a Sony Vaio laptop for Christmas which is running Vista Home Premium. It is model VGN-NR123E.  I have contacted Sony but they have not been able to help me.  The problem that I am having is that the wireless connection will drop without warning and to resume wireless connection I must shut down the computer and then restart it.  The computer might stay connected for as little as 5 minutes or a few hours.  I have the power setting set to Maximum Performance, and i'm useing a linksys wireless g router model WRT54G version 8.0.  Also when the computer loses the wireless connection and I try to reconnect before shutting down the computer it shows that that the computer does not have a wireless adapter installed. Any help would be greatly appreciated. Thanks for your time.  

  • nisorga
    1 Posts

    I am very new to Vista. Facing problem with WIFI. It seems , in my laptop i am getting wifi connection properly. But internet explorer or other browsers not working for some amazing reason.

    Any idea, what it can be ...

  • Nick White
    1204 Posts

    Hey jstewartak:  The hardware compatibility list is the place to go:  http://winqual.microsoft.com/HCL/ProductList.aspx?m=v&g=d&cid=700&sv=n.  Select 'networking' from the dropdown on the left of the home page and search on 'n'.  Certified for Windows Vista adapters are listed at the top (both x64 and x86).

  • jleznek
    1 Posts

    The hardware compatibility list has them. You can select "Networking"from the drop down on the left of the home page and searched on "N". Certified for Windows Vista adapters are listed at the top (x64 and x86).

    http://winqual.microsoft.com/HCL/ProductList.aspx?m=v&g=d&cid=700&sv=n

  • I just want to know a wireless adapter that is wireless N that will work with 64 bit VISTA.

    Thanks,

  • The connectivity in Vista is driving me crazy. Hence, that was how I gotten this blog. With XP, my connectivity is excellent. However, after recently upgrading to VIsta, it is only at 60%. I tried doing the above but it doesn't work. Is there anyway to overide this? As I was browsing the internet, I find many users having the same issue. I suppose it don't matter if you're saving the battery life. Most important is good connectivity. Whats the point of prolong battery life if downloading and uploading takes 3 times longer?! It's back to square 1!

  • What we need is a site showing which wireless adapters support Vista 32 bit and which support Vista 64 bit.  Right now, it is almost impossible to find a FAST (MIMO) wireless adapter that support Vista in any flavor.  We need Microsoft's help in this matter.

  • vash
    1 Posts

    how to i set the power saving mode for wireless adapter programatically??????

  • w0und3d
    1 Posts

    just an update:

    i could not dial, my 3g cards RAS. i created it via the Vista Dial up wizard...and it works. :)

  • w0und3d
    1 Posts

    thank you for the fix below!!! i was contemplating reinstalling XP. at least i can now install the software, and do not get the blue screen of death anymore! *just hope i can connect now!*

    Awesome, it works!

    thanks again for the post below!!!

    Basically, the device corresponding to "Texas Instruments PCI-xx21/x11 CardBus Controller with UltraMedia" (Hardware Id is VEN_104C&DEV8031) is not detected by Windows Update.  After installation of the correct driver, when inserting certain PCCards (Linksys Wireless-G Notebook Adapter with SRX, Linksys Wireless-N Business Notebook Adapter and Novatel Merlin V620 are examples) Vista BLUE SCREENS.

    The workaround I've found is to disable the "Texas Instruments PCI GemCore based SmartCard controller" (Hardware Id VEN104C&DEV_8035) installed by Vista, which then allows you to use the cards just fine (it is not a network driver issue).

  • cwood00
    3 Posts

    update - I'm still having the same issues afterall, the problems reocurred this morning. I'm running RC2, and changed the wireless power settings to maximum performance as suggested. Last night I manually clicked the 'sleep' button in Vista. This morning the wireless connection was trying to connect for 10 mins and never did so I unplugged the usb wireless adapter and replugged and it was connected within a few seconds. Lucky I have a removable adapter because the only other solution is to reboot. I'm hoping some other settings were changed before RTM... or maybe it is the d-link drivers I have? I'd be more than happy to email event logs to someone if that would help. cwood00(at)comcast.net

  • cwood00
    3 Posts

    So i'm pretty sure I've been having this exact issue - thanks for the post, very helpful. Resuming from sleep Vista is unable to connect to my wireless network by itself (using WPA PSK, d-link router). It doesn't happen every time confusingly - it tends to happen if the pc has been sleeping overnight. If I try to connect manually it tells me to check that i'm using the correct passphrase - which I am but there is a time-out while trying to authenticate. If I simply unplug my wireless usb adapter and plug it back in then it connects by itself automatically without any problems. I didn't have this problem with XP. The connection is otherwise perfectly stable while I'm sitting here using the pc. I changed the wireless setting as suggested in the post and it does seem to have made an improvement, no problems for the last few days - i'll let you know if it reoccurs.

  • Thanks For Information.

    ---------

    http://www.dl4all.com

  • Having some strange issues with PCMCIA on HP Compaq nc8230s (tried 3 different units) since Vista RC1 up to and including RTM.

    Basically, the device corresponding to "Texas Instruments PCI-xx21/x11 CardBus Controller with UltraMedia" (Hardware Id is VEN_104C&DEV8031) is not detected by Windows Update.  After installation of the correct driver, when inserting certain PCCards (Linksys Wireless-G Notebook Adapter with SRX, Linksys Wireless-N Business Notebook Adapter and Novatel Merlin V620 are examples) Vista BLUE SCREENS.

    The workaround I've found is to disable the "Texas Instruments PCI GemCore based SmartCard controller" (Hardware Id VEN104C&DEV_8035) installed by Vista, which then allows you to use the cards just fine (it is not a network driver issue).

    Oddly enough, My Avaya Wireless PC Card (Gold, 802.11b) card works fine either way.

  • Sephiroth
    35 Posts

    How about fixing (wired) printer network issues first?  I've found that systems running XP Pro or Home are having huge difficulties printing documents on a shared printer system running Vista.

    I don't know if this issue was resolved after the release of RC2 or not.  

  • My laptop (Dell XPS_Gen2 1.2gb ram)only gets 5 min. battery power with a new battery. Is this related to the wifi power issue?

  • I have trouble connectiong to the WLAN at home, which works fine in XP, I find the Connection keeps dropping for no apparent reason, then it takes Vista Ages to re-Authenticate and Connect. Whereas Xp does it with hardly a noticeable break in Connectivity.

  • Good to know, I hate a poor wireless connection.

    Unless I'm in an airport/hotel and not paying for it, in which case its tollerable!