Switching AC to Battery loses wireless IP address

Discussion in 'Wireless Networking' started by =?Utf-8?B?c2tpYnVtNDQy?=, Sep 18, 2004.

  1. IBM Thinkpad T41 with embedded Cisco card. All the latest drivers, bios,
    etc. IP address on wireless is lost when switching from battery to AC or AC
    to battery. Scenario: wireless working great, excellent signal. Pull out
    power cord. Within about a minute, connections fail, and IP address
    169.254.200.115 is assigned to wireless connection. Signal is still strong,
    but error message comes up saying "limited or no connectivity...". When I do
    a repair, the connection comes right back with a valid address and wireless
    works great again. Chatted with Microsoft XP2 support and IBM technical
    support. Nobody has ever heard of this before. Well, now you have!

    Other details:
    Using windows to configure my wireless networking
    WEP Open authentication
    Connect when this network is in range "enabled".
    Symptoms the same if firewall is on or off.

    My thoughts - something in the power event within the OS (or IBM's power
    management code) is killing the IP address - perhaps its going through a
    "should I suspend" logic and that is where the problem is. When the new
    power scheme is settled down (screen brightness lowered, etc), it does not do
    a DHCP request to regain its lost IP address.

    Looking forward to your comments and suggestions.
    =?Utf-8?B?c2tpYnVtNDQy?=, Sep 18, 2004
    #1
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  2. =?Utf-8?B?c2tpYnVtNDQy?=

    Robban Guest

    Hi,
    I have seen a similar case in this NG not that long ago. My recommendation
    was to check the power saving settings.
    There was nothing wrong with the standard Windows power settings, but the
    problem was solved by changing the power saving settings for the WLAN card
    to Maximum.

    br/rob

    "skibum442" <> wrote in message
    news:...
    > IBM Thinkpad T41 with embedded Cisco card. All the latest drivers, bios,
    > etc. IP address on wireless is lost when switching from battery to AC or

    AC
    > to battery. Scenario: wireless working great, excellent signal. Pull out
    > power cord. Within about a minute, connections fail, and IP address
    > 169.254.200.115 is assigned to wireless connection. Signal is still

    strong,
    > but error message comes up saying "limited or no connectivity...". When I

    do
    > a repair, the connection comes right back with a valid address and

    wireless
    > works great again. Chatted with Microsoft XP2 support and IBM technical
    > support. Nobody has ever heard of this before. Well, now you have!
    >
    > Other details:
    > Using windows to configure my wireless networking
    > WEP Open authentication
    > Connect when this network is in range "enabled".
    > Symptoms the same if firewall is on or off.
    >
    > My thoughts - something in the power event within the OS (or IBM's power
    > management code) is killing the IP address - perhaps its going through a
    > "should I suspend" logic and that is where the problem is. When the new
    > power scheme is settled down (screen brightness lowered, etc), it does not

    do
    > a DHCP request to regain its lost IP address.
    >
    > Looking forward to your comments and suggestions.
    >
    >
    Robban, Sep 18, 2004
    #2
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  3. Thanks for the reply. On your advice, I tried setting the wireless card to
    max power save (and the other two options as well), and saw no change to the
    symptoms. Also tried disabling power management in the control panel's power
    setting. When I switch AC to Battery, the screen flashes black for a
    millisecond and ends up dimmer than under full power. I have not found any
    control for that - to disable its routine - just in case that might fix it.

    "Robban" wrote:

    > Hi,
    > I have seen a similar case in this NG not that long ago. My recommendation
    > was to check the power saving settings.
    > There was nothing wrong with the standard Windows power settings, but the
    > problem was solved by changing the power saving settings for the WLAN card
    > to Maximum.
    >
    > br/rob
    >
    > "skibum442" <> wrote in message
    > news:...
    > > IBM Thinkpad T41 with embedded Cisco card. All the latest drivers, bios,
    > > etc. IP address on wireless is lost when switching from battery to AC or

    > AC
    > > to battery. Scenario: wireless working great, excellent signal. Pull out
    > > power cord. Within about a minute, connections fail, and IP address
    > > 169.254.200.115 is assigned to wireless connection. Signal is still

    > strong,
    > > but error message comes up saying "limited or no connectivity...". When I

    > do
    > > a repair, the connection comes right back with a valid address and

    > wireless
    > > works great again. Chatted with Microsoft XP2 support and IBM technical
    > > support. Nobody has ever heard of this before. Well, now you have!
    > >
    > > Other details:
    > > Using windows to configure my wireless networking
    > > WEP Open authentication
    > > Connect when this network is in range "enabled".
    > > Symptoms the same if firewall is on or off.
    > >
    > > My thoughts - something in the power event within the OS (or IBM's power
    > > management code) is killing the IP address - perhaps its going through a
    > > "should I suspend" logic and that is where the problem is. When the new
    > > power scheme is settled down (screen brightness lowered, etc), it does not

    > do
    > > a DHCP request to regain its lost IP address.
    > >
    > > Looking forward to your comments and suggestions.
    > >
    > >

    >
    >
    >
    =?Utf-8?B?c2tpYnVtNDQy?=, Sep 18, 2004
    #3
  4. Temp Fix: Switching AC to Battery loses wireless IP address

    Temporary fix: Turn off "Use windows to configure my wireless settings" in
    the wireless card property sheet. Use Cisco configuration utility, ACU to
    manually set up local networks. Downside is the loss of automatic functions.

    The above configuration changes worked for me. I can come and go from
    battery to AC power and my wireless network stays up. Microsoft support
    suggested turning off the warning that the network had become unavailable.
    That quieted down the message pop-ups, but did not solve the problem of a
    lost network.
    =?Utf-8?B?c2tpYnVtNDQy?=, Sep 19, 2004
    #4
  5. Since IBM has not heard of this, and neither have I, it might be safe to
    assume that there is some hardware problem and the card is behaving
    different in a low-power situation. The Repair functionality, as a last
    resort, stops and re-starts the network card driver, so it basically resets
    the hardware completely. I'm glad to hear that this at least fixes the
    problem. However, this is not the behaviour we want from our wireless,
    mobile laptops! I will ask a colleague if this problem has been reported
    before with Wifi hardware, though I suspect not.

    I would like to propose a test, but it would require using a different
    network card. If you could borrow a PCMCIA card from a colleague and do the
    same test it would be of great interest. Could this be done?

    Brian

    --
    Brian Wehrle

    Software Test Engineer/Wireless Networking
    Microsoft Corp.




    "skibum442" <> wrote in message
    news:...
    > Thanks for the reply. On your advice, I tried setting the wireless card
    > to
    > max power save (and the other two options as well), and saw no change to
    > the
    > symptoms. Also tried disabling power management in the control panel's
    > power
    > setting. When I switch AC to Battery, the screen flashes black for a
    > millisecond and ends up dimmer than under full power. I have not found
    > any
    > control for that - to disable its routine - just in case that might fix
    > it.
    >
    > "Robban" wrote:
    >
    >> Hi,
    >> I have seen a similar case in this NG not that long ago. My
    >> recommendation
    >> was to check the power saving settings.
    >> There was nothing wrong with the standard Windows power settings, but the
    >> problem was solved by changing the power saving settings for the WLAN
    >> card
    >> to Maximum.
    >>
    >> br/rob
    >>
    >> "skibum442" <> wrote in message
    >> news:...
    >> > IBM Thinkpad T41 with embedded Cisco card. All the latest drivers,
    >> > bios,
    >> > etc. IP address on wireless is lost when switching from battery to AC
    >> > or

    >> AC
    >> > to battery. Scenario: wireless working great, excellent signal. Pull
    >> > out
    >> > power cord. Within about a minute, connections fail, and IP address
    >> > 169.254.200.115 is assigned to wireless connection. Signal is still

    >> strong,
    >> > but error message comes up saying "limited or no connectivity...".
    >> > When I

    >> do
    >> > a repair, the connection comes right back with a valid address and

    >> wireless
    >> > works great again. Chatted with Microsoft XP2 support and IBM
    >> > technical
    >> > support. Nobody has ever heard of this before. Well, now you have!
    >> >
    >> > Other details:
    >> > Using windows to configure my wireless networking
    >> > WEP Open authentication
    >> > Connect when this network is in range "enabled".
    >> > Symptoms the same if firewall is on or off.
    >> >
    >> > My thoughts - something in the power event within the OS (or IBM's
    >> > power
    >> > management code) is killing the IP address - perhaps its going through
    >> > a
    >> > "should I suspend" logic and that is where the problem is. When the
    >> > new
    >> > power scheme is settled down (screen brightness lowered, etc), it does
    >> > not

    >> do
    >> > a DHCP request to regain its lost IP address.
    >> >
    >> > Looking forward to your comments and suggestions.
    >> >
    >> >

    >>
    >>
    >>
    Brian Wehrle [MSFT], Sep 21, 2004
    #5
  6. I put a Cisco 340 wireless card into the PC Card slot, brought it up on my
    WIFI/WEP network, and then switched from AC to battery and back. No network
    problems like with the embedded card, which is a Cisco 350. So - is it
    hardware or not? Because it fails when managed by Windows and works when
    managed by the Cisco configuration utility - its hard to say. I'll try to
    swap disks with a similar computer and see if the problem follows the disk.
    Thanks for your ideas on this Brian. We now at least have another hint to
    this obscure problem.

    "Brian Wehrle [MSFT]" wrote:

    > Since IBM has not heard of this, and neither have I, it might be safe to
    > assume that there is some hardware problem and the card is behaving
    > different in a low-power situation. The Repair functionality, as a last
    > resort, stops and re-starts the network card driver, so it basically resets
    > the hardware completely. I'm glad to hear that this at least fixes the
    > problem. However, this is not the behaviour we want from our wireless,
    > mobile laptops! I will ask a colleague if this problem has been reported
    > before with Wifi hardware, though I suspect not.
    >
    > I would like to propose a test, but it would require using a different
    > network card. If you could borrow a PCMCIA card from a colleague and do the
    > same test it would be of great interest. Could this be done?
    >
    > Brian
    >
    > --
    > Brian Wehrle
    >
    > Software Test Engineer/Wireless Networking
    > Microsoft Corp.
    >
    >
    >
    >
    > "skibum442" <> wrote in message
    > news:...
    > > Thanks for the reply. On your advice, I tried setting the wireless card
    > > to
    > > max power save (and the other two options as well), and saw no change to
    > > the
    > > symptoms. Also tried disabling power management in the control panel's
    > > power
    > > setting. When I switch AC to Battery, the screen flashes black for a
    > > millisecond and ends up dimmer than under full power. I have not found
    > > any
    > > control for that - to disable its routine - just in case that might fix
    > > it.
    > >
    > > "Robban" wrote:
    > >
    > >> Hi,
    > >> I have seen a similar case in this NG not that long ago. My
    > >> recommendation
    > >> was to check the power saving settings.
    > >> There was nothing wrong with the standard Windows power settings, but the
    > >> problem was solved by changing the power saving settings for the WLAN
    > >> card
    > >> to Maximum.
    > >>
    > >> br/rob
    > >>
    > >> "skibum442" <> wrote in message
    > >> news:...
    > >> > IBM Thinkpad T41 with embedded Cisco card. All the latest drivers,
    > >> > bios,
    > >> > etc. IP address on wireless is lost when switching from battery to AC
    > >> > or
    > >> AC
    > >> > to battery. Scenario: wireless working great, excellent signal. Pull
    > >> > out
    > >> > power cord. Within about a minute, connections fail, and IP address
    > >> > 169.254.200.115 is assigned to wireless connection. Signal is still
    > >> strong,
    > >> > but error message comes up saying "limited or no connectivity...".
    > >> > When I
    > >> do
    > >> > a repair, the connection comes right back with a valid address and
    > >> wireless
    > >> > works great again. Chatted with Microsoft XP2 support and IBM
    > >> > technical
    > >> > support. Nobody has ever heard of this before. Well, now you have!
    > >> >
    > >> > Other details:
    > >> > Using windows to configure my wireless networking
    > >> > WEP Open authentication
    > >> > Connect when this network is in range "enabled".
    > >> > Symptoms the same if firewall is on or off.
    > >> >
    > >> > My thoughts - something in the power event within the OS (or IBM's
    > >> > power
    > >> > management code) is killing the IP address - perhaps its going through
    > >> > a
    > >> > "should I suspend" logic and that is where the problem is. When the
    > >> > new
    > >> > power scheme is settled down (screen brightness lowered, etc), it does
    > >> > not
    > >> do
    > >> > a DHCP request to regain its lost IP address.
    > >> >
    > >> > Looking forward to your comments and suggestions.
    > >> >
    > >> >
    > >>
    > >>
    > >>

    >
    >
    >
    =?Utf-8?B?c2tpYnVtNDQy?=, Sep 22, 2004
    #6
  7. Symptom update

    When WEP is disabled, symptoms disappear (ie, I can switch from AC to Battery
    back and forth with no loss of IP address, no need to repair). When WEP
    encryption is enabled, I always lose address when switching from AC to
    Battery or back - and repair always fixes it. Result: SP2 reduces security
    because workaround is to remove WEP from wireless.
    =?Utf-8?B?c2tpYnVtNDQy?=, Oct 28, 2004
    #7
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