Will plugging in Ethernet Cable mid-WiFi Screen Share disconnect link?

Discussion in 'Mac Basics and Help' started by jman995x, Feb 10, 2014.

  1. jman995x macrumors regular

    Joined:
    Sep 8, 2007
    #1
    I'm in the middle of doing a Screen Share / Large File Transfer and just realized that I'm doing this via WiFi. Realizing that this is going to take some time, I thought I might plug in the CAT5 Ethernet cable from my modem into the back of my iMac, but fear that I might interrupt the transfer.

    On another note, if I finish transferring the file, THEN decide to switch over to CAT5 (vs. WiFi), will this disconnect me from the target computer? The person who owns the other computer has gone out for the night, so if I get disconnected, there's no way I can continue with the project/transfer until they grant me access again.

    J.
     
  2. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #2
    Yes... no matter how you do this, switching from a wifi connection to an ethernet connection is going to stop the download and drop the connection to the other machine.
     
  3. glenthompson macrumors 68000

    glenthompson

    Joined:
    Apr 27, 2011
    Location:
    Virginia
    #3
    If heis not dropping the wifi but adding another network connection, will it drop it? How does OS X handle multiple network connections? If you have both a wifi and Ethernet connection, will it send data over both interfaces?
     
  4. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #4
    It will use only one at a time. If they are both connected, it will use whichever one is at the top of the list in this Set Service Order setting.

    [​IMG]

    In the OP's case, he will be (albeit quickly) dropping the wifi connection and picking up the ethernet connection. They will both be live connections with an IP address for each, but apps will only use the ethernet connection.

    The problem is getting apps to use the second connection. By default OS X apps are going to use that main connection at the top of the service order list.

    There are Terminal commands you can issue to make something like SSH communicate over the other connection, but nothing I have ever seen to make a regular app do it.

    In many server environments there are multiple ethernet connections and the server software can tell an app to use a particular ethernet connection. But not in desktop OS X.
     
  5. glenthompson macrumors 68000

    glenthompson

    Joined:
    Apr 27, 2011
    Location:
    Virginia
    #5
    Probably far more information than the OP wanted but very helpful for me. Thanks for the info. I need to learn more about OS X networking.
     
  6. ElectricSheep macrumors 6502

    ElectricSheep

    Joined:
    Feb 18, 2004
    Location:
    Wilmington, DE
    #6
    In this case, as long as WiFi remains active the file transfer will not be interrupted.
     
  7. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #7
    I believe it would depend on how the set service order is arranged. If ethernet is at the top and you connect an ethernet cable it will switch over to ethernet and drop the wifi transfer, even though the wifi connection is still live. At least that is how mine seems to work. Have you tested and found differently?

    I have Display ethernet (Thunderbolt Display) set at the top and if I am logged in and on wifi when I connect it switches over to ethernet immediately and anything that was going on over the wifi gets dropped.

    I'm not trying to be argumentative... I am genuinely curious if you see different behavior. :)
     
  8. ElectricSheep macrumors 6502

    ElectricSheep

    Joined:
    Feb 18, 2004
    Location:
    Wilmington, DE
    #8
    I tested a file transfer out of screen sharing just last evening half a dozen times, ensuring that Ethernet was the preferred interface in the service order. The transmission was not interrupted. Only when bringing down the interface on which the file transfer was initiated was there an interrupted.

    All things being equal, this is expected. As long as the wireless interface remains active and has a distinct IP address from the newly brought up ethernet interface, nothing has changed from a Network Layer perspective.

    What would be impacted is DNS resolution. If an operation relies on name resolution, then there may be issues if the new higher-priority interface does not resolve to the same DNS servers as the previous one.
     
  9. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #9
    Thanks for replying. Perhaps mine behaves differently because the ethernet connection is coming over the TB cable through the display.
     

Share This Page