Vista uses wi-fi rather than Ethernet for LAN traffic?

Discussion in 'Windows Vista Networking' started by turnstyle, Dec 4, 2007.

  1. turnstyle

    turnstyle Guest

    Hi all,

    I have a Vista laptop that generally uses wi-fi to connect to the
    local network via, but sometimes I plug in the Ethernet (when I need
    to do big file transfers).

    If I open Task Manager > Networking tab, I can see that Web browser
    traffic spikes up within the "Local Area Connection" -- however, local
    file sharing (ie, copying files between the laptop and other PCs on
    the LAN) is over the wi-fi.

    Any advice? Thanks! -Scott
    turnstyle, Dec 4, 2007
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  2. In general, Windows will use both networks interfaces at the same time. If
    one channel becomes full it will begin usage on the other. It picks one to
    start the connection and then holds on to that for the duration of the
    transfer, (unless something goes wrong and it has to try again). With
    browser traffic multiple connections are made (for the various parts of a
    web page). So in this case the first connection may be WiFi, now that
    connection is busy the second connection is made to the wired interface. In
    the case of a file transfer, a connection is opened and that connection is
    used for the transfer. (A second concurrent transfer would open another
    connection on the other interface).

    In your case the priorities for the two interfaces are probably the same and
    the WiFi is 'first' in the list of available interfaces. You can set the
    'cost' of the two interfaces to be different and that will bias the
    This is done in the advanced settings of the properties of TCP/IP for IPV4.
    This is the 'metric' for the device. The higher number the lower the
    priority. the IP protocol will start a connection with the connection that
    is currently unused and has the lowest metric, So if you set the metric for
    the wireless to 2 and the metric for the wired to 1 the selection will be
    biased to start on the wired if both are available.

    I would simply turn off the wireless on the laptop myself. (most laptops
    make that easy with a button so that they can be used on a plane).

    Vista Home premium
    Michael Walraven, Dec 4, 2007
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  3. turnstyle

    turnstyle Guest

    Hi Michael, thanks.

    I've actually tried manually setting the metric priority of both
    adapters (wire=1, wi-fi=2), and also used the "advanced" proerties to
    place the wired adapter ahead of the wireless.

    If I boot connected to the wire, then everything passes over the wire.
    If I disconnect the wire, then everything passes over wi-fi. If put
    the wire back in, then Web traffic passes over the wire, but local
    traffic remains on the wi-fi.

    Anything else I might try?

    (I understand that I can turn off the radio, but I'd love to make this
    "just work" if possible!)

    thanks again, -Scott
    turnstyle, Dec 4, 2007
  4. It is possible that the system only pays attention to the metric on initial
    boot so that later changes are not taken into account I do not have enough
    knowledge to make a real statement there.

    I have assumed that you have the wireless and the wired both going to the
    same router. There was a recent thread concerning a setup where one was
    connected to a corporate web and the other to an external web. I made some
    suggestions as to prioritizing the DNS servers in that case but I don't know
    how well that worked out.

    I have a setup that is what I assumed you have, the wireless is connected to
    the same router as my wired.
    Vista will do its best to optimized the operation so I just let it do its

    Have you tried timing the copying of a large file to see if it really slows
    things down under both connected vs. just the wired?

    Michael Walraven, Dec 4, 2007
  5. turnstyle

    turnstyle Guest

    I'm not in any dual-network situation -- just a home LAN, with a few
    PCs behind the router.

    And it is definitely slower when Task Manager indicates that the
    traffic is over wi-fi rather than the wire (I had even wondered if it
    might be a Task Manager cosmetic bug rather than something funky with
    the network).

    Do you have both wi-fi and wire available, Vista laptop? It's easy for
    me to reproduce:

    1) boot with both wire and wireless connections

    2) open Task Manager > Networking tab

    3) browse the Web and copy a file over the LAN -- you should see both
    over the wired connection

    4) unplug the Ethernet

    5) browse the Web and copy a file over the LAN -- you should see both
    over the wireless connection

    6) plug the Ethernet back in

    7) browse the Web and copy a file over the LAN -- now the Web traffic
    shows up under the wired connection, and the local file copy under the

    I'd certainly be very interested to know if the same happens for you
    -- but I understand it's a bit of a chore, so no worries!

    turnstyle, Dec 4, 2007
  6. Interesting the way it works. (note that the machine with both interfaces is
    still an XP).

    Both interfaces plugged in (the wireless is a PC card), power up for a
    wakeup from hibernate.
    The link for the wireless is established, the wired interface is
    established. Begin a transfer it occurs only over the wired interface, the
    wireless is ignored - as if it had not completed its setup.

    Unplug the wired, transfer fails, did not automatically transfer to
    wireless, the wireless completes the setup and announces that it is ready.
    Started transfer again and it start over the wireless (natch, wired is
    unplugged.) Plug the wired back in announced that it was connected again,
    but did not start using it for transfers.

    Stopped the transfer. Restarted (now both are connected) began with the
    wireless after awhile (this was a 1GB transfer) the wired kicked in also.
    The wired was running about 0.4%, the wireless running 25%

    My times
    Wireless only 12:30
    Wired only 01:57
    Added wireless , only used wired 01:56
    remove wired, but wired back in only used wired 01:57

    tried to get to internet ... Dog Slow!!!..
    repaired wireless, repaired wired, now network fast again, getting a
    streaming video, only used wired
    repaired wired, repaired wireless, network fast only used wireless.

    My results (on XP!!) are that if the wired is available it is used in
    preference to the wireless. (both for local and internet)

    Wish I had a Vista with both to test.
    Michael Walraven, Dec 4, 2007
  7. whoops should have been

    repaired wired, repaired wireless, network fast only used wired. ******

    Michael Walraven, Dec 4, 2007
  8. turnstyle

    turnstyle Guest

    So, even though we're now comparing XP to Vista, you'd also say that
    it didn't work as expected?

    Per earlier, I could always manually turn off the radio when I want to
    force the Ethernet connection -- but it just bugs me because it seems
    like this should work.

    Did you check your 'metric' settings?

    turnstyle, Dec 4, 2007
  9. on the XP test, if the wired was available then it was used for both local
    and internet. The wireless was used only if the wired was not there. I was
    expecting it to use both so was a little suppressed. It ended up using the
    faster link that was good.

    (additional point - my hardwire link was 100 Mb, the ethernet was 54 Mb.)

    Michael Walraven, Dec 5, 2007
  10. turnstyle

    turnstyle Guest

    I thought here you meant that the wire didn't work right after you
    plugged it back in:
    Doesn't that mean very poor wire performance?

    turnstyle, Dec 5, 2007
  11. Scott,
    VERY poor performance. When the wired is working correctly it registers 66%
    (100 Mb).

    The poor performance was after plugging in the wired while the wireless was
    working. There seems to be an effect that depends on the order in which they
    are plugged in.

    Michael Walraven, Dec 5, 2007
  12. turnstyle

    turnstyle Guest

    And the weird bit here is that after I reconnect the wire, Web browser
    traffic then passes over the wire, but local file sharing traffic
    stays on the wi-fi.

    Any lukers on this thread? What happens if you try it?
    turnstyle, Dec 6, 2007
  13. Just an additional thought. Could there be an effect of the IP address
    assigned by the router?
    That is does a 'lower' number perhaps get priority??
    Michael Walraven, Dec 6, 2007
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